The Lorna Prieta, California, Earthquake of 

October 17, 1989-Recovery, Mitigation, 

and Reconstruction 

JOANNE M. NIGG, Editor 

SOCIETAL RESPONSE 

DENNIS S. MILETI, Coordinator 

UeSe GEOLOGICAL SURVEY PROFESSIONAL PAPER 1553-D 

Prepared in cooperation with the National Science Foundation 

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1998 

CONTENTS 

Macroeconomic effects of the Loma Prieta earthquake ..................... 3 

By Raymond J. Brady and Jeanne B. Perkins 

Sheltering and housing of low-income and minority groups in Santa 

Cruz County after the Loma Prieta earthquake ............................ 17 

By Brenda D. Phillips 

Local earthquake mitigation programs: perceptions of their effectiveness 

The State of California's response to the Loma Prieta earthquake -------- 63 

By Charles C. Thiel, Jr., George W. Housner, and L. Thomas Tobin 

Earth science, earthquake response, and hazard mitigation: lessons from 

the Loma Prieta earthquake ................................................... 81 

By William M. Brown I11 and Carl E. Mortensen 
THE LOMA PRIETA, CALIFORNIA, EARTHQUAKE OF OCTOBER 17,1989: 

SOCIETAL RESPONSE 

RECOVERY, MITIGATION, AND RECONSTRUCTION 

INTRODUCTION 

By Joanne M. Nigg, 

Disaster Research Center, University of Delaware 

The papers in this chapter reflect the broad spectrum 

of issues that arise following a major damaging urban 

earthquake-the regional economic consequences, 

rehousing problems, reconstruction strategies and 

policies, and opportunities for mitigation before the next 

major seismic event. While some of these papers deal with 

structural or physical science topics, their significant 

social and policy implications make them relevant for 

improving our understanding of the processes and 

dynamics that take place during the recovery period. 

Brady and Perkins provide a macro-level analysis of the 

economic consequences that the Loma Prieta earthquake 

had on the San Francisco Bay region. They conclude that 

effects of the quake on the regional economy were 

minimal, despite a large amount of structural losses, 

especially in Santa Cruz County. Although the quake did 

cause some economic disruption, the availability of 

redundant transportation systems and relief assistance 

greatly reduced its impact. 

Two papers deal with the issue of sheltering and rehousing people displaced by the earthquake. Phillips looks at 

how socially vulnerable groups of victims in Santa Cruz 

County-the elderly, the already homeless, and low-income Latinos- were affected over a 2-year recovery period. She concludes that rehousing these groups was not 

approached in a comprehensive manner and that a variety 

of pre-existing social conditions actually added to the 

problems of sheltering and rehousing. In her assessment 

of housing problems that arose in San Francisco and 

Watsonville following the earthquake, Comerio investigates the linkage between pre-disaster mitigation efforts 

and reconstruction of the housing stock. She concludes 

that the rate of reconstruction varies greatly depending 

on several local factors. 

I 

The importance of mitigation during the post-earthquake 

recovery period is also addressed in three of the other papers 

in this chapter. Bolton and Oriens propose that the Loma Prieta 

earthquake provided a test of how well the National Earthquake Hazard Reduction Program's efforts have promoted 

local-level mitigation activities. They conclude that local officials believe that seismic elements of the State of California's 

building code were effective in limiting the extent of damage 

in their communities, but also that those officials were not 

likely to recognize the extreme importance of site characteristics as factors affecting structural damage. Bolton and 

Oriens' second conclusion is reinforced by Tyler and Mader 

in their investigation of how Santa Cruz County and some of 

its mountain residents became locked in a conflict over a land 

use issue. The County would not issue house rebuilding permits on sites with evidence of earthquake-caused ground failure, although residents claimed willingness to assume all risks 

and try to get their disrupted lives back to some state of normalcy. The paper by Thiel, Housner, and Tobin reviews the 

Board of Inquiry's recommendations to the Governor of California concerning design and policy needs to mitigate future 

earthquake damage to the State's transportation infrastructure systems (bridges and highways). They conclude that while 

much had been done in the two decades before the Loma 

Prieta earthquake, more aggressive efforts to mitigate future 

consequences are needed. 

Brown and Mortensen, in the concluding paper, stress the 

importance of incorporating the Earth science community 

more fully into the organizations and agencies that manage 

earthquake hazard reduction activities. They maintain that 

response and mitigation decisions should be based on the best 

available scientific information and that this expertise must 

become institutionalized in order for it to be available in a 

timely manner to decisionmakers. 
THE LOMA PRIETA, CALIFORNIA, EARTHQUAKE OF OCTOBER 17,1989: 

SOCIETAL RESPONSE 

PUBLIC RESPONSE 

MACROECONOMIC EFFECTS OF' THE EARTHQUAKE 

By Raymond J. Brady and Jeanne B. Perkins 

Association of Bay Area Governments, Oakland, Calif. 

CONTENTS Page 

Abstract ........................................................................... 

Introduction.. ................................................................... Methodology.. .................................................................. Techniques for assessing the employment 

impacts.. ........................................................... Techniques for assessing the retail sales 

impacts.. ........................................................... Techniques for assessing the wage and total 

output loss associated with the earthquake.. .............................................................. Analysis of the macroeconomic impacts of the 

earthquake.. ...................................................... Analysis of county or PMSA employment 

impacts.. ........................................................... Santa Cruz County ............................................. San Benito County ............................................. Monterey County ............................................... Oakland PMSA .................................................. 

San Francisco PMSA ......................................... San Jose PMSA ................................................. Santa Rosa-Petaluma and Vallejo-FairfieldNapa PMSA's ................................................... Analysis of county taxable sales impacts ................. Santa Cruz County ............................................. San Benito County ............................................. Monterey County ................................................ Alameda County ................................................. 

Contra Costa? Marin? and Napa Counties .......... San Francisco County ......................................... San Mateo County .............................................. Santa Clara County ............................................. Solano and Sonoma Counties ............................. Analysis of wage and output impacts ...................... 

Analysis of economic disruption impacts ................ 

Employment impact into the year 1990 ................... 

Why the minimal economic impact? ....................... 

Assessing economic impacts from possible damage 

patterns in future earthquakes .......................... 

Assessing macroeconomic impacts on the 

basis of damage scenarios ................................ 14 

Policy applications of analysis of the economic 

impacts of earthquakes. ...................................... 15 

Conclusions.. ................................................................... 15 

Acknowledgments ........................................................... 15 

References.. ..................................................................... 15 

ABSTRACT 

The Loma Prieta earthquake produced minimal disruption 

to the overall economy of the Bay Area and its environs. Our 

research indicates that approximately 7?100 workers were laid 

off as a result of the earthquake. The actual number could be 

higher because not all workers are eligible for unemployment claims. However? a statistical analysis of the employment data suggests that the actual number is close to that 

estimate. This disruption lasted a maximum of 4 months? with 

a direct potential loss of wages and salaries of about $54 million, resulting in a minimum potential loss in gross output 

(including wages and salaries) of about $110 million during 

this period. The total economic disruption resulted in an estimated maximum potential Gross Regional Product (GRP) loss 

ranging from $725 million in I month to $2.9 billion over a 

maximum of 2 months following the quake. However, at least 

80 percent of that loss was recovered during the first and 

second quarters of 1990. This implies that the maximum GRP 

lost as a result of the Loma Prieta earthquake ranges from 

$18 1 million to $725 million. 

These losses? when compared to the total size of the regional economy, can only be viewed as minor. For example? 

the potential short-term loss of approximately 7,100 jobs over 

an average duration of 4 months amounts to a loss of less 

than 0.25 percent of the jobs in an economy of more than 3 

million jobs. The GRP loss is even smaller when compared to an economy with a GRP of $174 billion in 1989. 

This economic loss is even small in comparison to the 

direct physical damage due to the earthquake of $5.9 billion. The economic loss was primarily concentrated in retail and selected manufacturing activity. 

San Francisco experienced the greatest loss in retail 

activity for the fourth quarter. Data analysis indicates the 
D4 RECOVERY, MITIGATION, AND RECONSTR UCTION 

loss of approximately $73 million in taxable sales. This 

loss was, however, not regionally felt. Economic activity 

merely shifted to other parts of the region. Because the 

only direct damages which were disproportionately high 

in San Francisco were to transportation and power facilities, this suggests the critical role that transportation and 

infrastructure play in maintaining economic activity and 

gives a glimpse of the potential impact on the economy 

from a major failure of these systems in a future earthquake. 

The job losses were most severe in Santa Cruz County, 

which experienced an 85 percent increase in unemployment insurance claims for the period from the third week 

of October to the second week of November over the same 

period in 1988. In 1988, the unemployment claims were 

3,910; in 1989, they jumped to 7,246. Statistical analysis 

suggests that the actual total employment for November 

1989 was, at a minimum, about 1,700 jobs less than would 

have been likely without an earthquake. The reduction for 

December was similar to that for November. 

To perform these analyses, we used a methodology built 

around an input-output model of the San Francisco Bay 

Area previously developed by Association of Bay Area 

Governments (ABAG) staff. This work illustrates how secondary impacts of earthquakes can be measured in large 

urban areas. The methodology is designed as a quickresponse mechanism to give policy makers estimates of 

macroeconomic loss based on sets of data and assumptions about duration of earthquake impacts on economic 

activity. 

INTRODUCTION 

The Loma Prieta earthquake was felt by millions of 

people over an area covering approximately 400,000 

square miles (StatelFederal Hazard Mitigation Survey 

Team, 1990). The earthquake caused more than $5.9 billion in direct property damage and disrupted transportation, communications, and utilities (State Office of Emergency Services, Region 11, unpublished communication, 

Sept. 27, 1990). A breakdown of the damage patterns is 

provided in table 1. How did this damage and disruption 

translate into impacts on the region's economy? 

Macroeconomic impacts are defined as recordable disruptions in business activity and employment. These impacts are viewed as short-term economic phenomena and 

are differentiated from property loss impacts. The objective of this report is to identify the macroeconomic impacts of the Loma Prieta earthquake. 

METHODOLOGY 

The macroeconomic impacts of the Loma Prieta earthquake are of three major types: (1) the employment impacts, (2) the impacts on regional sales, and (3) wage and 

output impacts. 

TECHNIQUES FOR ASSESSING THE 

EMPLOYMENT IMPACTS 

The most effective and simplest way to assess 

employment impacts is to view the data over time and to 

compare the data trends with those of other historical 

periods. Therefore, the initial step in this analysis was to 

plot month-by-month employment data for selected 

counties and Primary Statistical Metropolitan Areas 

(PMSA's) in the immediately affected region. The 

following areas were analyzed: 

Santa Cruz County 

San Benito County 

Monterey County 

Oakland PMSA (Alameda and Contra Costa 

Counties) 

San Francisco PMSA (Marin, San Francisco, San 

Mateo Counties) 

San Jose PMSA (Santa Clara County) 

Santa Rosa-Petaluma PMSA (Sonoma County) 

Vallejo-Fairfield-Napa PMSA (Napa and Solano 

Counties) 

The monthly data for 1988 were compared against monthly 

data for 1989 to identify changes in trend that could be associated with the Loma Prieta earthquake. These trend data are 

identified in figure 1. Next, Auto Regressive Integrated Moving Average (ARIMA) and least squares time series models 

were developed for each county or PMSA. Data used in the 

ARIMA models covered the 12 months of 1988 and 10 months 

in 1989. For the least squares models, the data series covered 

the period from September 1988 to September 1989. The independent variable in the linear least squares models was 

California employment for the month. ARIMA and least 

squares models were used as a check against each other. An 

ARIMA is not likely to pick up macroeconomic "noise" in 

the data, since it calculates the forecast on the trend. 

A macroeconomic downturn would show up in these data 

and could be differentiated from the rise in unemployment or 

slowdown in job growth that was specifically related to the 

earthquake. Both forecasting techniques were used to predict numbers for November and December 1989. If the forecast employment was greater than the actual employment, 

the difference was analyzed using both forecasting techniques 

to identify the Loma Prieta earthquake impact. 

Unemployment Insurance (UI) claims data were collected 

from the California Employment Development Department 

(EDD) from the third week in October to the second week of 

November for both 1988 and 1989. The difference between 

the claims from these two periods was analyzed. 

Two critical assumptions were made. First, it was assumed 

that 80 percent of the difference was associated with the 

earthquake. There was some concern that an assumption of 

100 percent leaves little room for microeconomic disruptions 

that had nothing to do with the earthquake, such as a plant 
MACROECONOMIC EFFECTS OF THE EARTHQUAKE 

Table 1~Estimated Loma Prieta earthquake damage in San Francisco and Monterey Bay Area counties 

[Source: California Governor's Office of Emergency Services (OES), Region 11, Sept. 27, 1990, except as otherwise noted below] 

- - - - 

Amount of Alameda Contra Marin Monterey San S an S an Santa Santa Solano Total 

Damage County Costa County County Benito Francisco Mateo Clara Cruz County 

Couny County County 1 County County County 

Total damage, 

in millions of 

dollars 

Homes 

damaged 

Uninhabitable 

housing units2 

Businesses 

damaged 

Businesses 

destroyed 

Road damage, 

in millions of 

dollars3 

Public utility 

damage, in 

millions of 

dollars 

PG&E losses, in 

millions of 

dollars4 

(Combined 

with San Mateo 

and Santa 

Clara 

Counties) 

~ata on homes damaged and businesses destroyed and damaged are taken from San Francisco City Planning Department, March 

1991. The numbers are higher than those in the OES data. "Destroyed" numbers include those destroyed in the earthquake and those 

red-tagged and demolished. "Damaged" numbers include those secured or yellow-tagged. The number of dwelling units in residential 

buildings destroyed or secured was known, and all units are included in the totals. However, the numbers may be low for damaged homes 

due to an assumption of one unit per building for yellow-tagged buildings. Similarly, for commercial and industrial facilities, it was assumed 

that there was a single business per building, which underestimates the actual number of impacted businesses. 

2~ata from Perkins and others (1996). 

^~ata from the Region Ll OES Damage Assessment Surveys for local roads were added to data from a written communication from 

Caltrans District 4 Earthquake Damage Status Report as of September 14, 1990 and both written and oral communications from Districts 5 

and 10 staff. San Francisco-Oakland Bay Bridge repairs are included in the values for Alameda County, not San Francisco. In addition, all 

Region I1 OES values were checked with the counties. This process resulted in an increase for Monterey County. 

^~ata from Pacific Gas and Electric Co. (PG&E), Insurance Dept. (written commun., Sept. 1991). Data supplied by PG&E multi-county 

region. Region boundaries follow, but are not identical to, county boundaries. Damage for the East Bay Region (Alameda and Contra Costa 

Counties) appears under those counties in this table. Damage for the Redwood Region (Marin, Sonoma, Napa, and a small portion of Solano 

County) appears under Marin County in this table. Damage for the Mission Trail Region (Monterey, San Benito, most of Santa Clara, and 

Santa Cruz Counties) appears under Santa Clara and Santa Cruz Counties. Damage for the Golden Gate Region (San Francisco, the 

headquarters offices, San Mateo, and a very small portion of Santa Clara County) appears under San Francisco and San Mateo Counties. 

Because much of Solano County is in the Sacramento Valley Region, the total damage for this large area is listed under this single county. 

The $0.6 million damage in the San Joaquin Valley Region and $10 million of indirect costs do not appear in this table except in the "Total" 

column. 

closing, or for general macroeconomic disruptions, such which "claim loads returned to normal levels within 

as a general slowdown in growth. Therefore, the 80 percent four weeks" (California Employment Development 

value appears reasonable. Second, it was assumed that the Department, 1990a). 

economic disruption in employment and output lasted a After estimating the number of UI claims, we compared 

maximum of four months. This conservative assumption these numbers against the employment estimates by the 

was based upon an analysis by the California EDD, in ARIMA or least squares for each PMSA or county. 
D6 RECOVERY, MITIGATION, AND RECONSTRUCTION 

TECHNIQUES FOR ASSESSING THE RETAIL 

SALES IMPACTS 

Taxable sales data were collected from the California Board 

of Equalization for 12 quarters covering the period 1987- 1989 

for the 12 counties affected by the Loma Prieta earthquake. 

Data were plotted by quarter for the periods 1987-1988 and 

1988-1989. The 1987-1988 data were used as a benchmark 

to identify quarterly trend data. The 1988-1989 series was 

plotted on the same graph to ascertain whether the quarterly 

patterns were similar. When it was clear that the slope change 

between the third and fourth quarters of 1988 differed from 

that between the same quarters in 1989, an ARIMA and least 

squares were used to predict the taxable sales for the fourth 

quarter based upon trend data for the 12 quarters. 

TECHNIQUES FOR ASSESSING THE WAGE AND 

TOTAL OUTPUT LOSS ASSOCIATED WITH THE 

EARTHQUAKE 

After the employment losses were calculated, wage and 

salary losses were calculated for each county affected by the 

earthquake. Using county business patterns data from the U.S. 

Commerce Department, average annual wages per employee 

were calculated for 1989. The average wage by county was 

multiplied by the employment loss. 

Since, as explained in the section on "Techniques for Assessing the Employment Impacts," it was assumed that the 

duration of layoffs due to the earthquake was 4 months, the 

average annual wages were multiplied by 4/12 to obtain wage 

and salary loss for this shorter period. Next, using data on the 

ratio of wages to gross output gathered when updating the 

ABAG regional input-output table, an estimate of the gross 

output loss associated directly with the employment loss was 

calculated. The average duration of the loss was assumed to 

cover 4 months. 

An estimate of the decline in potential gross output associated with economic disruption was calculated for the 12- 

county area. The disruption affected output where employment layoffs were associated with the earthquake. This 

potential decline in gross output reflects the minimum potential loss due to the earthquake. 

Finally, an estimate of the range of regional gross output 

disrupted by or lost due to the earthquake was calculated. 

This estimate was based upon the gross output for the quarter 

for the 12-county area. Of this estimated value, most was 

recovered in the months following the earthquake. However, 

a conservative estimate was developed of the total loss in 

gross output that was not recovered. 

Throughout this process, several assumptions have been 

made. The overriding rule, however, has been to make these 

assumptions maximize the impacts of the earthquake, to 

the extent practical. Thus, if the conclusion of this effort is 

that the impact on total regional output is small, this 

conclusion was reached in spite of the assumptions made 

during the analysis. 

ANALYSIS OF THE MACROECONOMIC 

IMPACTS OF THE EARTHQUAKE 

ANALYSIS OF COUNTY OR PMSA EMPLOYMENT 

IMPACTS 

Monthly employment trends for 1988 and 1989 for the 12 

counties within the study area are plotted in figure 1. For the 

9-county Bay Area, the areas were delineated by PMSA. There 

are 5 PMSA's in the Bay Area, identified in the section "Methodology." Individual data exist for the counties of Monterey, 

San Benito, and Santa Cruz. 

Table 2 identifies unemployment claims for the period from 

the third week in October through the second week in November for the years 1988 and 1989. The data give a relatively good picture of the direct job impacts of the Loma Prieta 

quake. As described in the previous section, it was assumed 

that between 70 and 90 percent of the increase in unemployment claims was associated with the earthquake. This varies 

by county or PMSA. It was assumed that 90 percent of the 

increase in claims in Santa Cmz County was associated with 

the quake and that 70 percent of the increase in the San Jose 

PMSA was so associated. The lower value of 70 percent was 

used for the San Jose PMSA because of an economic slowdown independent of the earthquake. The assumption for all 

other areas was 80 percent. 

Using the above assumptions, we estimated that approximately 7,100 of the total 8,619 increase in claims during this 

period were associated with the earthquake. More than 42 

percent of the estimated increase in claims due to the earthquake were located in Santa Cmz County. San Francisco 

PMSA (Marin, San Francisco, and San Mateo Counties) accounted for about another 20 percent of the increase. The 

Oakland PMSA accounted for about 15 percent, and the San 

Jose PMSA share was about 12 percent of the total. San Benito 

and Monterey Counties accounted for the remaining 11 percent of the claims. 

SANTA CRUZ COUNTY 

Figure 1A shows that the trend of employment growth in 

Santa Cruz County was disrupted in October 1989. Unemployment claims increased by 3,336 from the third week in 

October to the second week of November 1989. An ARIMA 

model was developed to predict nonagricultural employment 

for November and December 1989, based upon 20 months of 

time series covering 1988 and 1989. The predicted value using the ARIMA model for November 1989 was 84,800 jobs. 

The actual number of jobs was 83,100, or 1,700 jobs lower 

than the predicted value. The model has a range of 82,500 to 

87,000, at a 95 percent confidence value. This analysis shows 

that the employment should have been higher than it was based 

upon monthly trends, the difference being assigned to the 

earthquake. The difference between the actual value (83,100) 

and the high end of the ARIMA predicted value (87,000) is 
1 MACROECONOMIC EFFECTS OF THE EARTHQUAKE D7 

Table 2.-Unemployment claims in Bay Area counties affected by 

the earthquake for the third week in October through the second 

week in November 

[Source: Effects of the October 17, 1989 Earthquake on Employment (California 

Employment Development Department, 1990a) p. 7-8.1 

Area 

Santa Cruz 

County 

San Benito 

County 

Monterey 

County 

Oakland PMSA 

San Francisco 

PMSA 

Assumed Calculatd 

percent of earthqua 

increase increase due ke-related 

t o increase 

earthquake 

San Jose PMSA 

Total 

greater than the calculated earthquake increase of 3,002. 

Therefore, our assumptions seem reasonable. For December, 

the predicted value is 84,100, which is 1,800 jobs higher than 

the actual employment; the upper limit of the ARIMA model's 

prediction is 87,700 with a 95 percent confidence value. 

Hence, the model tended to verify the observed increase in 

UI claims as shown in figure 2, and the decline in employment as identified in figure 1A. 

SAN BENITO COUNTY 

San Benito County was close to the earthquake's epicenter, but the economy was only marginally affected. Figure 

1B shows the trend in employment in 1988 and 1989. No 

discernible shifts in growth could be identified. Unemployment claims increased by 284 during the period. 

An ARIMA developed for nonagricultural jobs for 20 

months covering 1988 and 1989 indicates a predicted level 

of jobs greater than the actual. For November the forecast 

suggests 8,263 jobs in the county. The actual number is 8,075. 

The difference is close to the number of claims filed. In December, 8,414 jobs were forecast for the County and the actual number was 8,100 jobs. This indicates continued weakness into December in the local economy. 

MONTEREY COUNTY 

Unemployment claims in Monterey County increased by 

684 individuals for the period from the third week in October through the second week in November of 1989 over the 

same period in 1988. An ARIMA model was constructed to 

predict November and December 1989 nonagricultural employment. These predicted data were compared with 

the actual data (figure 1C) for the period. The actual employment in November 1989 was 112,200, and in December it was 111,800. The comparison tends to verify that the 

quake did have some impact on the county's employment 

growth. The ARIMA forecast for jobs in November 1989 

was 600 higher than the employment reported by EDD. In 

December, the forecast was 400 jobs higher than the number reported by EDD. The difference in the forecast and 

actual numbers appears to be confirmed by the jump in 

unemployment claims. However, the increase clearly is minimal when compared to the total jobs in the county. 

OAKLAND PMSA 

The Oakland PMSA consists of Alameda and Contra Costa 

Counties. As shown in figure ID, the quake had minimal 

impact on job growth during the affected period. In fact, the 

graph shows an acceleration of job growth for October-December 1989 over the same period in 1988. Although unemployment claims did jump by 1,368 during this period, when 

compared to the same period in 1988, the increase appears to 

have been limited to the Berkeley-Oakland area. The Hayward-Fremont areas farther south experienced a jump of about 

392 claims during the week of October 28 over the same period in 1988. However, the number of claims dropped dramatically after this week. Kroll and others (1 99 1) speculated 

that "employment trends in the East Bay (Oakland MSA) suggest that the earthquake may have induced a mini boom for 

the end of October and the month of November in some sectors, in portions of Alameda and Contra Costa Counties undamaged by the earthquake." 

The increase in UI claims associated with the quake in an 

economy of 900,000 plus jobs can only be viewed as insignificant. To statistically verify that conclusion a least-squares 

model was constructed for the Oakland PMSA. The independent variable was nonagricultural employment in the state. 

The dependent variable was nonagricultural employment in 

the Oakland PMSA. The 9 for the model was 0.92 and the 

DW statistic was 2.13, indicating little bias in the model. The 

results of the simulation indicated that the predicted growth 

was less than the actual. In short, economic conditions in the 

PMSA were not inhibited by the Loma Prieta earthquake. 

SAN FRANCISCO PMSA 

The San Francisco PMSA consists of Marin, San Francisco, 

and San Mateo Counties. Unemployment claims increased 

by 1,729 in the PMSA over the same period in 1988. Approximately 78 percent of this increase was in the County of 

San Francisco. Most of the job loss in San Francisco was in 

retail activity. This loss is verified by figure 3H, which shows 

a major slump in taxable sales in San Francisco, probably 

due to transportation disruption. 
D8 RECOVERY, MITIGATION, AND RECONSTRUCTION 

$ [B San Benito County 

2 6 llllll.llll 

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 

.Id 

7 70 .- 0 

5 

Monterey County 1 

- - 

65-A Santa Cruz County - 

8901~~~~~~

* Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 

5 60 lllll Illll 

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 

I 

D Oakland PMSA lllllllll 

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 

E San Francisco PMSA 8 800 lllllllll 

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 

San Jose PMSA 

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 

f 160 

150 

.- c 140 

6 9 130 .- - $ 120 - 

3 

2 110 

8' 

- loo 

Santa Rosa-Petaluma PMSA lllllllll 

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 

Vallejo-Fairfield-Napa PMSA 

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 

Figure 1. Monthy trends in total nonagricultural employment for San Francisco Bay Area counties during 1988 and 1989 (before and just 

after the Lorna Prieta earthquake of October 17, 1989). Data from California EDD (1990) and ABAG files. 
MACROECONOMIC EFFECTS OF THE EARTHQUAKE 

The overall employment impact in the PMSA was not significant. The job losses accounted for approximately 0.2 percent of total jobs in the PMSA during this period. Figure 1E 

shows that the trends of employment for the months of October-December 1989 were very similar to those for the same 

period in 1988. 

SAN JOSE PMSA 

The San Jose PMSA consists of Santa Clara County in the 

southern portion of the Bay Area. Unemployment claims 

jumped by 1,2 18 for the period from the third week in October through the second week in November 1989 over the same 

period in the previous year. Thirty-seven percent of the increase was in the Gilroy area? in southern Santa Clara County. 

Approximately one-third of the increase was in the Sunnyvale area? in the northwestern corner of the county. A major 

fraction of this increase in claims is associated with hightech layoffs unrelated to the quake. Figure 1 F indicates a general weakening of employment growth through the year 1989? 

independent of the quake in October. The graph shows a jump 

in employment in December 1989 in sectors normally affected 

by an economic disruption such as an earthquake. More than 

50 percent of the increase from November to December was 

associated with retail trade activity. An ARIMA model of 

monthly employment data from January 1988 to October 1989 

was developed to predict November and December 1989 employment for the PMSA. The model predicted a November 

employment level about 2?000 jobs greater than the actual? 

but nearly 157000 lower than the actual for December. The 

confidence band for the November forecast of 836?400 jobs 

was about k 3.5 percent. The confidence band for the December forecast of 8207300 jobs deteriorates to about k 5 

percent. Therefore? the statistical model is not useful in this 

case7 primarily because the trends illustrated in figure 1 F show 

a general economic weakening throughout 1989. Therefore? 

it is argued that little or no evidence exists that Loma Prieta 

affected economic activity in Santa Clara County in a statistically measurable way. 

SANTA ROSA-PETALUMA AND VALLE JO-FAIRFIELD-NAPA 

PMSA7S 

The Santa Rosa-Petaluma PMSA consists of Sonoma 

County7 and the Vallejo-Fairfield-Napa PMSA consists of 

Napa and Solano Counties. 

These counties are in the northern Bay Area and farthest 

from the quake7s epicenter. Figures 1 G and 1 H indicate little 

or no impact from the quake. Unemployment claims verify 

this statement. Although the Vallejo-Fairfield-Napa PMSA 

did see an increase in claims during this period and a slowing 

in job growth? these conditions are totally attributable to the 

early stages of the existing recession, since the losses were 

associated with residential construction activity. 

ANALYSIS OF COUNTY TAXABLE SALES 

IMPACTS 

In addition to examining the potential employment impacts 

of the earthquake? we analyzed the impact on retail sales to 

determine the effects of the earthquake on consumer behavior during this period. 

SANTA CRUZ COUNTY 

Given the employment impact of the earthquake in Santa 

Cruz7 one would expect that a measurable impact on retail 

sales also would have been felt. However? as figure 3A illustrates? the trend for the affected quarter is quite similar to that 

of 1988. To verify this observation, an ARIMA model was 

used to predict taxable sales. Data covered the period from 

the first quarter of 1987 to the third quarter of 1989? or 11 

quarters of data. The forecast for the fourth quarter 1989 was 

$4607930,000 in taxable sales. The actual amount was 

$45679007000 in taxable sales. The difference is less than 1 

percent and statistically insignificant. Therefore? it appears 

from these quarterly data that the quake had little or no impact on sales activity. 

One factor minimizing the impact of such losses in Santa 

Cruz may have been the availability of relief funds for temporary tents to house those businesses displaced in the downtown area. Some businesses also were able to relocate to other 

areas of the county7 minimizing the county-level impact (even 

though sales tax revenues in the city of Santa Cruz dropped). 

Another factor may have been the strong economic base of 

Santa Cruz as the site of an expanding University of California campus, and as a southern annex of Santa Clara County7s 

"Silicon Valley.?? Finally? spending may have increased as 

people replaced or repaired those items damaged or destroyed. 

SAN BENITO COUNTY 

Figure 3B shows little or no impact from the earthquake in 

the fourth quarter 1989 retail sales patterns for San Benito 

I I I I I I 

2nd week 3rd 

4th I lstweek 2nd 3rd 4th 

October November 

Figure 2. Number of unemployment claims filed in Santa Cruz 

County during October-November 1988 and October-November 

1989 showing affect of Loma Prieta earthquake of October 17,1989. 

Data from California EDD (1990). 
Dl0 RECOVERY, MITIGATION, AND RECONSTRUCTION 

County. In fact, sales in the quarter jumped substantially 

higher than the trend for the same period in 1988. 

MONTEREY COUNTY 

Figure 3C indicates that the earthquake had little or no 

impact on taxable sales in Monterey County in the fourth 

quarter of 1989. An ARIMA model for the same period forecast a taxable sales level 1.4 percent higher than the actual 

data. This difference is considered statistically insignificant. 

In short, it is not likely that the difference was the result of 

the quake. 

ALAMEDA COUNTY 

Alameda County is part of the Oakland PMSA. Figure 3D 

identifies the taxable sales data for the county. 

The graph shows that the trends over the 1987-1988 and 

1988-1989 periods are similar on a quarterly basis. The second and third quarters of 1989 actually were better than those 

in 1988. The fourth quarter appears to have flattened out. An 

ARIMA model, however, for the period forecast a lower fourth 

quarter than the actual taxable sales. Therefore, little or no 

evidence exists that the quake disrupted taxable sales in 

Alameda County in the fourth quarter of 1989. 

CONTRA COSTA, MARIN, AND NAPA COUNTIES 

Figures 3E, 3F, and 3G illustrate taxable sales activity for 

Contra Costa, Marin, and Napa Counties. The trend data show 

little or no disruption in taxable sales activity in these counties over this period. 

SAN FRANCISCO COUNTY 

Figure 3H identifies taxable sales activity in San Francisco 

County. The graph does suggest a shift in the retail sales activity trend for the fourth quarter of 1989. Various statistical 

techniques were used to measure the expected against the 

actual retail activity. An ARIMA mode1 forecast sales $73 

million above the actual. A statistical least squares, using California taxable sales as an independent variable, forecast taxable sales $31 million higher than the actual data. Some of 

this loss in potential retail activity can be associated with the 

drop in tourism, which is estimated to be a $3-billion annual 

business in San Francisco. Another source of the loss is associated with a shift of retail activity from San Francisco to 

other counties in the region. This shift may have been due, in 

part, to the damaged bridge access to San Francisco. A shortterm power outage in the Financial and Marina districts may 

have exacerbated this problem. ARIMA models of retail activity for the fourth quarter 1989 for Alameda, Contra Costa, 

and San Mateo Counties indicated higher retail sales than 

Santa Cruz County I I f I 

I 2 3 4 I 2 3 4 

Quarter 

I 70

San Benito County 

I I I I I 

E 2 3 4 I 2 3 4 

Quarter 

c Monterey County 

400 I I I I 1 

1 2 3 4 I 2 3 4 

Quarter 

D Alameda County I I I I I . . I 2 3 4 I 2 3 4 

Quarter 

Figure 3. Trends in taxable retail sales in San Francisco Bay Area 

counties during 1987-1988 and 1988-1989 (before and just after the 

Lorna Prieta earthquake of October 17,1989). Data from California 

Board of Equalization (1989 and 1990) and ABAG files. 
MACROECONOMIC EFFECTS OF THE EARTHQUAKE Dl 1 

1,200 

Contra Costa County 

. . 

1 2 3 4 1 2 3 4 

Quarter 

- Marin County I I I I I 

1 2 3 4 1 2 3 4 

Quarter 

G Napa County f! 100 I I I I I 

1 2 3 4 1 2 3 4 

Quarter 

r 

1 2 3 4 1 2 3 4 

Quarter 

% 1,250 

San Mateo County I I I I I 

- - 

H San Francisco County 

1 2 3 4 1 2 3 4 

Quarter 

8 1,000 I I I 1 I 

J Santa Clara County 

3,000 '/ I I I I I 

1 2 3 4 1 2 3 4 

Quarter 

K Solano County 1 300 I I I I I 

1 2 3 4 1 2 3 4 

Quarter 

1 2 3 4 1 2 3 4 

Quarter 

Figure 3. Continued. 
Dl2 RECOVERY, MITIGATION, AND RECONSTRUCTION 

expected for the quarter. A portion of this increase can be 

attributed to a shift in retail activity away from San Francisco 

County to other counties in the Bay Area. 

This shift points to a potentially significant reason why the 

Bay Area7s economy was not substantially affected by the 

quake. As noted earlier, a major portion of the loss in economic activity in San Francisco may have been due to a loss 

in transportation access. This suggests that lack of widespread 

infrastructure damage minimized the economic impact of the 

earthquake. 

SAN MATE0 COUNTY 

Figure 31 shows retail activity in the fourth quarter of 1989 

in San Mateo County. The graph suggests that the trend in 

this activity was not disrupted by the earthquake. This is verified by an ARIMA model of retail activity which forecast a 

lower level of growth than actually occurred. 

SANTA CLARA COUNTY 

Figure 3J identifies taxable sales activity in Santa Clara 

County over a period covering 1987-1989. Little or no identifiable quake impact can be observed from the trend data. 

An ARIMA model for taxable sales for the County covering 

the period from the first quarter 1987 through third quarter 

1989 was developed. The model results confirmed that the 

actual sales exceeded expected sales for the fourth quarter of 

1989. 

SOLANO AND SONOMA COUNTIES 

Figures 3K and 3L cover Solano and Sonoma Counties, 

located in the northern portion of the Bay Area. Both graphs 

show little or no impact from the quake on taxable sales in 

these counties. 

ANALYSIS OF WAGE AND OUTPUT IMPACTS 

As noted earlier, long- or short-tern job disruption affected 

more than 7,100 individuals after the Loma Prieta earthquake. 

In order to estimate the impact of this disruption, the average 

wages of the affected individuals were estimated. It was beyond the scope of this project to develop a profile of the workers affected by the earthquake. Therefore? wage and salary 

losses reflect averages for the specific county or PMSA. Table 

3 shows average wage and salary levels in 1989 for the affected counties. 

After identifying the average wage and salary for 1989 for 

each affected area, we estimated the number of workers affected. The affected workers were defined as the difference 

(1989 versus 1988) in the claims for the period from the third 

week in October through the second week in November multiplied by a fraction. That is7 it was assumed that the workers 

affected by the quake were not responsible for all of the increase. For Santa Cruz County, it was assumed that 90 percent of the increase was earthquake related. For Monterey 

and San Benito Counties, and for the Oakland and San Francisco PMSA's? the estimate was 80 percent. For the San Jose 

PMSA? the estimate was 70 percent. The 70 percent figure 

was chosen because an economic slowdown independent of 

the earthquake was already occurring in the San Jose PMSA. 

Next? we estimated the lost income. Data on the actual duration of unemployment were not available? so we assumed 

that the average maximum duration of a layoff due to the 

earthquake was 4 months. This assumed maximum duration 

of unemployment represents one-third of the year without 

income. This value was multiplied by the annual wage and 

salary to obtain lost income. The resulting figure reflects 

maximum income lost, because unemployment benefits received during this period were not subtracted from the wage 

and salary lost. The wage and salary losses estimated in this 

way from reported unemployment due to the earthquake are 

shown for the affected areas in table 4. 

After calculating wage and salary losses due to the increase 

in unemployment7 we estimated the impact on output. In the 

Bay Area? employee compensation accounts for about 49 

percent of the total value of output of industries. This average is found by calculating the employee compensation component of industry inputs developed by ABAG as part of its 

regional input-output model. The reciprocal of this employee 

compensation fraction multiplied by the wage and salary lost 

results in an estimate of the value of output affected directly 

by the employee reductions. This value is $110.2 million for 

the region. 

ANALYSIS OF ECONOMIC DISRUPTION IMPACTS 

The economic disruption of the earthquake was then calculated. For purposes of this analysis, a set of assumptions, 

based on professional judgment? were made to ensure that 

the impacts of the quake were not underestimated. We assumed that? at a minimum? 10 percent of the Bay Area's 

economy was affected for a period of one month, and, at a 

maximum, 20 percent of the region's economy was affected 

for two months. It was further assumed that? at a maximum7 

productivity fell by 50 percent over the affected period in 

affected industries. The resulting indirect economic disruption in the third quarter of 1989 cost the region7s economy, in 

lost Gross Regional Product (GRP)? about $725 million to 

$2.9 billion? depending upon the assumptions. 

Finally? it was assumed that 75 percent of the lost productivity or production was recovered during the first and second quarters of 1990. Thus? the permanent loss from the earth- 
MACROECONOMIC EFFECTS OF THE EARTHQUAKE D 13 

Table 3.-Average annual wage and salary by county or Primary 

Metropolitan Statistical Area (PMSA) in 1989 

Table 4.-Estimated income losses from the earthquake by county 

or Primary Metropolitan Statistical Area (PMSA) 

[Source: U.S. Dept. of Commerce Bureau of Economic Analysis, Wage and Salary 

Data 19901 

Santa Cruz County 

San Benito County 

Monterey County 

Oakland PMSA 

San Francisco PMSA 

San Jose PMSA 

quake in terms of potential GRP is between $18 1 million and I 

$725 million. This amount is quite small compared to the 

ABAG estimate of the GRP for 1989 of $174 billion, in spite 

of the effort to ensure that the assumptions on which this analysis is based would tend to maximize, to the extent reasonable, the impacts of the quake. 

Although it is difficult to attach definite numbers to these 

values, anecdotal conversations with businesses in the Oakland-Berkeley area, as well as in Silicon Valley, tended to 

confirm these assumptions. For example, a survey of seven 

major Silicon Valley firms determined that the vast majority 

of their operations were back on line on October 18 or 19. 

Dates for full operational recovery ranged from October 18 

or 19 (two firms), November 1989 (one firm), first quarter 

1990 (two firms), to second quarter 1990 (two firms). 

EMPLOYMENT IMPACT INTO THE YEAR 1990 

Figure 4 illustrates unemployment rates over the period July 

1989-June 1990 for PMSA's and selected counties in the San 

Francisco and Monterey Bay regions. It shows a jump in unemployment rates in Monterey, San Benito, and Santa Cruz 

Counties and the San Jose PMSA starting in October 1989. 

t 

3 Jul Aug Sep Oct Nov Dec 1 Jan Fob Mar Apr May Jun 

1989 1 1990 

--A- Oakland PMSA Ã‘~ San Francisco PMSA -4- San Jose PMSA 

- Monterey County + San Benito County Santa Cruz County 

Figure 4. Trends in unemployment rates for selected San Francisco 

Bay Area counties and Primary Metropolitan Statistical Areas 

(PMSA's) between July 1989 and June 1990, showing effect of the 

Loma Prieta earthquake of October 17, 1989. Data from California 

EDD (1990b). 

Santa Cruz County 

San Benito County 

Monterey County 

Oakland PMSA 

San Francisco PMSA 

San Jose PMSA 

Total $53,900,000 

In Monterey and San Benito Counties almost all of the continued increase is associated with seasonal agricultural employment. In Santa Cruz County, after an initial increase from 

October to November, the rate stabilized but then began to 

increase again in January 1990. The increase in January is 

associated primarily with seasonal employment. Overall, the 

unemployment statistics show no long-term lingering impact 

on employment from the Loma Prieta quake. 

WHY THE MINIMAL ECONOMIC IMPACT ? 

Given that the Loma Prieta earthquake caused more than 

$5.9 billion in property damage, why was the macroeconomic 

impact so small in comparison to the area's more than $170- 

billion GRP and more than 3 million jobs? This is a critical 

question because it gives us insight into both the flexibility 

and vulnerability of the region's economy. 

Some might argue that luck played a key role in minimizing macroeconomic disruptions to the Bay Area's total 

economy. Economic impact was substantial only in isolated 

areas where the direct earthquake damage was concentrated 

(see table 1). Even in areas such as Santa Cruz County, the 

macroeconomic impacts were not "major" if viewed in the 

context of an entire county. Even if one assumes that the 3,300 

jump in unemployment claims was minimal, and that the actual number of workers affected was 1,000 more, or 4,300, 

this number still represents only about 6 percent of the total 

jobs in the county. 

One also could argue that the primary reason the earthquake had a minimal affect on the macroeconomic factors in 

the Bay Area was that the transportation and other forms of 

infrastructure were minimally damaged at the regional level. 

The damage and disruption to the Bay Bridge connecting San 

Francisco with the East Bay is a good indicator of how a 

major disruption of the transportation network could affect 

economic activity. It is hypothesized that the decline in taxable sales in San Francisco is directly related to the closure of 

the Bay Bridge for several weeks from October to November 

1989. The damage to the Cypress freeway structure in Oakland minimally affected regional transportation activity because alternative routes were readily available. However, economic impacts of approximately $20 million annually were 
Dl4 RECOVERY, MITIGATION, AND RECONSTRUCTION 

documented in a recent report (Bay Area Economic Forum 

and Metropolitan Transportation Commission, 1990). Had 

major freeways been disrupted throughout the Bay Area for 

any length of time, it is likely that economic activity would 

have been more substantially affected. 

One can also argue that the complexity of the regional 

economy generates redundancies that serve to localize the 

impact of businesses displaced by building damage. A good 

example is the City of Santa Cruz, which, from an economic 

perspective, can be viewed as a southern annex to Santa Clara 

County's Silicon Valley. Localized impacts there were minimized because businesses were able to relocate to other areas 

of Santa Cruz County. Such redundancies found in an urban 

area are not present in a more rural area, such as Coalinga. 

Finally, one must give credit to the high level of emergency 

preparedness among the major industrial leaders in Silicon 

Valley. In contrast to firms in someother Bay Area (and national) industrial areas, these industries are relatively young, 

and the structures in which they are located are relatively new. 

Some of these companies are also national leaders in the retrofit of nonductile concrete structures, or had abandoned such 

buildings (in part due to earthquake concerns) well before 

the earthquake. In addition, because of the rapidly changing 

technology in which these industries are engaged, the process equipment and contents of the buildings tend to be completely replaced about every five years. Thus, the companies 

have frequent opportunities to upgrade the quality and safety 

of their equipment and the means by which it is secured against 

earthquake damage. 

ASSESSING ECONOMIC IMPACTS FROM 

POSSIBLE DAMAGE PATTERNS IN 

FUTURE EARTHQUAKES 

The previous section focused on the direct macroeconomic 

disruptions in the San Francisco Bay Area that resulted from 

the Loma Prieta earthquake. Our analysis suggests that the 

economy was minimally affected because of (1) the location 

of the quake, and (2) minimal damage to the overall infrastructure of the region. 

Developing a methodology to assess potential, as well as 

actual, impacts is an essential step to improve the way economic costs of earthquakes are evaluated. This section focuses on an existing model used at ABAG to assist in evaluating the potential economic costs of earthquakes. Kawashima 

and Kanoh (1990) used interindustry analysis (input-output 

analysis) to look at the indirect economic effects of an earthquake in Japan. Munroe and Ballard(1983) also developed a 

statistical modeling technique to assess the indirect economic 

effects of a natural disaster. The model used in the San Francisco Bay Area is structurally similar to that used by 

Kawashima and Kanoh since it is a regional input-output 

model (Brady and Yang, 1988). The model is part of a larger 

forecasting system that integrates economics and demographics to forecast growth and change (Brady and Yang, 1983). 

ASSESSING MACROECONOMIC IMPACTS ON 

THE BASIS OF DAMAGE SCENARIOS 

The system developed in the San Francisco Bay Area can 

be used to assess the macroeconomic impacts of an earthquake on the basis of various damage scenarios. This process 

is possible because input-output models allow one to view an 

economy in terms of linkages between sectors. In addition, 

the model structure makes assessing impacts relatively easy. 

The usefulness of the system lies in providing better and more 

timely information to formulate policy both on preparing for 

and on responding to crises. 

It is useful to examine two possible damage scenarios to 

provide a better understanding of the possible impact of property damage on the region's economy. These scenarios use 

input-output analysis to illustrate that what is damaged is more 

important than how much is damaged. 

Scenario 1: Damage from an earthquake is concentrated 

in the Silicon Valley and in southern Alameda County. The 

freeway network is heavily damaged, and preliminary assessment indicates that 10 percent of the high-technology business activity has been affected. Because of the extent of darnage, business activity will be disrupted for a period of six 

months. What is the economic impact of this disruption to 

overall economic activity in the Bay Area? 

In 1989, ABAG estimated that the output value of computers, electronics, and instruments produced in the Bay Area 

was $20.4 billion. Almost 85 percent of the output was located in the southern portion of the Bay Area. The impact of 

this damage scenario was to reduce output for these sectors 

to $19.5 billion for the year. This is a $900-million impact, 

with a potential loss of 7,500 jobs in these sectors. What is 

the region-wide impact of this potential disruption? The model 

suggests that the region-wide impact will be about 12.6 percent higher than that on the individually affected industries, 

or $113.5 million more, with the loss of an additional 4,500 

jobs. Most of this loss is concentrated, by rank of affect, in 

four Bay Area industries: wholesale trade; finance, insurance, 

and real estate (FIRE); fabricated metals; and business and 

professional services. These combined industries account for 

about 3,700 jobs lost due to the secondary impacts. There are 

two main conclusions: (1) any disruption to high-technology 

manufacturing would be more costly to the economy for this 

scenario than that which actually occurred in the Loma Prieta 

earthquake, and (2) although a higher direct impact occurs 

for this scenario than for the following scenario, the secondary economic impacts are concentrated in a select number of 

industries. 

Scenario 2: The Bay and Golden Gate Bridges are substantially damaged for a period of up to six months. Initial 

economic analysis using the Bay Area input-output model 
MACROECONOMIC EFFECTS OF THE EARTHQUAKE Dl5 

indicates that this will affect the economic activity offinance, 

insurance, and real estate (FIRE); business and professional 

services; and retail activity. Analysis suggests that the disruption will reduce the supply of FIRE services by 5percent, 

business services by 5 percent, and retail activity by 1 percent for up to six months. This reduction comes from having 

to shift office or retail operations, a fall-off in demand due to 

fear, and a general disruption of the productivity of these 

activities. 

The basic analysis of this scenario suggests that about $1 

billion in output from the region's economy would be directly 

affected by the reductions identified above. However, the secondary impacts on the Bay Area economy are far more substantial than for the previous scenario. In scenario 1, overall 

regional output falls by about 0.4 percent as a result of the 

disruption of the identified industries. Under scenario 2, regional output falls by 1.1 percent, which is more than double 

the disruption associated with scenario 1. In particular, disruption of business services and FIRE is the principal cause 

for computer output to fall by 5 percent, electronics to have a 

decline in output of about 4 percent, and instruments to also 

decline in output by about 4 percent. The primary reason for 

the impact on manufacturing is that financial and business 

services contain both capital and labor resources that feed 

into these sectors. Any disruption in the flow of these services affects economic activity. 

POLICY APPLICATIONS OF ANALYSIS OF THE 

ECONOMIC IMPACTS OF EARTHQUAKES 

The above simple analysis helps identify those sectors that 

could disrupt overall economic activity, if affected by an earthquake. This approach allows one to develop profiles of earthquake impact on economic activity. These profiles, in turn, 

could enter into policy discussion on several types of issues. 

First, with regard to decisions about allocating financial and 

labor resources among repairing, maintaining, or strengthening highway networks and infrastructure, information provided by this process can assist in answering questions such 

as, "How can the choke points in the highway network be 

minimized in those locations that have sensitive industries?" 

Second, following an earthquake the process can help in identifying where to allocate scarce resources after initial damage information assesses the potential industries affected. Any 

allocation process should focus on getting the economy back 

on its feet as soon as possible. Such a process requires information about which industries can most disrupt the overall 

system. 

CONCLUSIONS 

The overall macroeconomic damage to the Bay Area's 

economy as a result of the Loma Prieta earthquake was minimal. One reason for this minimal disruption appears to rest in 

the fact that the highway and rail network was not substantially damaged. If both the Bay Area Rapid Transit (BART) 

system and highway network had been damaged, it is likely 

that the economic disruption would have been substantial. 

Maintaining the Bay Area's infrastructure as a functional system should be a top priority before and after future earthquakes. 

Building property damage is not a good indicator of economic disruption. One factor minimizing the impact of property damage losses on the economy of Santa Cruz County 

may have been the ready availability of relief funds for temporary tents to house those businesses displaced in the downtown area. Some businesses in downtown Santa Cruz also 

were able to relocate to other areas of Santa Cruz County. 

Another factor may have been the strong economic base of 

Santa Cruz as the site of an expanding University of California campus, and as a southern extension of Santa Clara 

County's Silicon Valley. 

Input-output analysis is a simple system to identify and 

evaluate those industries that might substantially affect the 

macroeconomy of the Bay Area. It will help both in doing 

preparatory work in this area and in assessing the dislocation 

impacts after an earthquake occurs. 

ACKNOWLEDGMENTS 

We would like to thank the following individuals for their 

thoughtful comments: Kenneth Ballard, Pacific Gas and Electric Company; Catherine Bauman, City and County of San 

Francisco; Charles Eadie, City of Santa Cruz; Cynthia Kroll, 

University of California, Berkeley; Joel Markowitz, Metropolitan Transportation Commission; and Sarah Nathe, California Office of Emergency Preparedness. In addition, we 

would like to thank Leslie Freeman for her assistance in data 

collection. 

The production of this paper was financed in part with a 

grant from the National Science Foundation (NSF). The report does not reflect the views of any Federal agency, including NSF. 

REFERENCES 

Bay Area Economic Forum and Metropolitan Transportation Commission, 1990, The missing transportation link: Economic 

impacts of the closure of the Cypress freeway on the San Francisco Bay area: Bay Area Economic Forum and Metropolitan 

Transportaion Commission, Oakland, CA, 18 p. 

Brady, Raymond J., and Yang, Chin M., 1983, The design and implementation of a regional economic-demographic simulation 

model : The Annals of Regional Science, v. XVII, n.3, p. 1-22. 

Brady, Raymond J., and Yang, Chin M., 1988, 1982 input-output 

model and economic multipliers for the San Francisco Bay region - 1988 Update: Association of Bay Area Governments, 

Oakland, CA, 49 p. 
Dl6 RECOVERY, MITIGATION, AND RECONSTRUCTION 

California Board of Equalization, 1989 and 1990, Taxable sales data 

by county for California: California Board of Equalization data 

report. 

California Employment Development Department (EDD), 1990, 

Effects of the October 17,1989 earthquake on employment: 

California EDD Report, p. 6. 

California Employment Development Department (EDD), 1990b, 

Report 400r-Coastal: California EDD data report. 

Kawashima, Kazuhiko, and Kanoh, Takashi, 1990, Evaluation of 

indirect economic effects caused by the 1983 Nihonkai-chubu, 

Japan, earthquake: Earthquake Spectra, v.6, n.4, 1990, p. 739- 

754. 

Kroll, Cynthia A., Landis, John D., Shen, Qing, and Stryker, Shen, 

199 1, Economic impacts of the Lorna Prieta earthquake: A 

focus on small business: University of California, Berkeley, 

Institute of Business and Economic Research, Berkeley, CA, 

40 p. 

Munroe, Tapan, and Ballard, Kenneth P., 1983, Modeling the economic disruption of a major earthquake in the San Francisco 

Bay area: Impact on California: The Annals of Regional Science, v.XVI1, n.3, p. 23-40. 

Perkins, J.B., Chuaqui, Ben, Harrald, John, and Jeong, Dukhoon, 

1996, Shaken awake! Estimates of uninhabitable dwelling units 

and peak shelter populations in future earthquakes affecting 

the San Francisco Bay region: Oakland, Association of Bay 

Area Governments, Publication P96002EQK, 143 p. 

San Francisco City Planning Department, 1991, San Francisco's 

Loma Prieta experience: City of San Francsico Planning Department. 

StatelFederal Hazard Mitigation Survey Team, 1990, State and Federal hazard survey team report for the October 17, 1989 Loma 

Prieta, California: FEMA-845-DR-CA, 73 p. 

U.S. Department of Commerce Bureau of Economic Analysis, 1990, 

Wage and salary data. 
THE LOMA PRIETA, CALIFORNIA, EARTHQUAKE OF OCTOBER 17,1989: 

SOCIETAL RESPONSE 

RECOVERY, MITIGATION, AND RECONSTRUCTION 

SHELTERING AND HOUSING OF LOW-INCOME AND 

MINORITY GROUPS IN SANTA CRUZ COUNTY 

AFTER THE LOMA PRIETA EARTHQUAKE 

By Brenda D. Phillips 

Texas Woman's University 

CONTENTS Page 

Abstract ......................................................................... Dl7 

Introduction.. ................................................................. Literature review.. ......................................................... Disasters, socioeconomic status, and 

minority groups .............................................. 

Disasters and the elderly ...................................... 

.................................. F isasters and the homeless 

our phases of sheltering and housing ................ Housing in California .......................................... Methodology.. ............................................................... Interviews.. .......................................................... Observation.. ........................................................ Systematic documentation ................................... Community context ....................................................... Santa Cmz County and City ................................ Watsonville.. ........................................................ 

Earthquake damage to housing ..................................... Santa Cmz ........................................................... Watsonville.. ........................................................ Overview of sheltering and housing ............................. Emergency sheltering .......................................... The homeless ............................................. The elderly ................................................. Low-income Latinos .................................. Temporary sheltering ........................................... The homeless ............................................. The elderly ................................................. Low-income Latinos .................................. 

Overview of emergency and 

temporary sheltering phases ........................... Temporary housing .............................................. The elderly ................................................. Low-income Latinos .................................. Permanent housing .............................................. 

The elderly ................................................. Low-income Latinos .................................. Overview of permanent housing ......................... Summary.. ............................................................ 

Conclusion.. .................................................................. Affordable housing .............................................. Inclusivity and diversity ....................................... Interorganizational coordination and 

communication.. ............................................. Acknowledgments.. ....................................................... References.. ................................................................... 

ABSTRACT 

An assessment was made of how the Loma Prieta earthquake of October 1989 displaced the elderly, the homeless, 

and low-income Latinos in Santa Cruz County. The longitudinal research design included 117 in-depth interviews with 

sheltering and housing-related organizations that responded 

to the needs of low-income and minority victims. The main 

conditions found to have affected displacement, besides the 

earthquake, were a lack of affordable housing, ethnic differences and traditions not fully anticipated by emergency 

preparedness officials, and heightened post-disaster 

interorganizational coordination and communication. 

INTRODUCTION 

After the Loma Prieta earthquake struck northern California in October 1989, fires and damaged freeways in San Francisco and Oakland caught the world's attention. In Santa Cmz 

County, farther south, the earthquake caused considerable 

damage to residential housing areas and nearly complete devastation of single-room-occupancy (SRO) hotels in downtown 

Santa Cruz. A long period of housing recovery loomed. 
Dl8 RECOVERY, MITIGATION, AND RECONSTRUCTION 

The cities of Santa Cruz and Watsonville contained specific population groups adversely affected by the earthquake. 

In Santa Cruz, elderly residents lost SRO hotel housing. 

Watsonville, a predominantly Latino community, witnessed 

extensive damage to low-income housing. In both these communities, the earthquake further reduced housing opportunities for those already homeless. 

This paper assesses the impact of the earthquake on those 

who were already homeless or were made homeless among 

the elderly and Latino groups. It focuses on the problems of 

short-term sheltering and long-term housing. Given that recent census data indicate increasing minority populations in 

American society (Schwartz and Exter, 1989), such a study 

imel y. 

LITERATURE REVIEW 

DISASTERS, SOCIOECONOMIC STATUS, AND 

MINORITY GROUPS 

Disasters affect low-income victims more negatively than 

middle- and upper-class victims (Bolin and Bolton, 1986; 

Bolin, 1982). For example, lower class homeowners and renters are more likely to live on or near flood plains and other 

hazards, are less likely to carry disaster-related insurance, and 

typically take longer to recover from a disaster. Discrimination against minority groups results in their concentration in 

lower socioeconomic levels. One result is that minority groups, 

such as Latinos, experience difficulty in obtaining adequate 

and affordable housing (Bolton and others, 1992). Minority 

groups therefore carry a higher risk in disasters. 

Empirical support exists for the contention that disasters 

hit minority and majority groups differentially. Furthermore, 

communities generally are not adequately prepared to meet 

culturally diverse needs (Perry and Mushkatel, 1986; Phillips, 

1993). For example, Aguirre (1988; see also National Research Council, 1991) found that a lack of appropriate bilingual warning systems probably contributed to the 26 deaths 

in a Saragosa, Texas, tornado. 

strained familial relationships and mental health problems. 

SRO residents prefer to live alone. These elderly are at risk 

from earthquakes in part because of precarious and (or) inadequate housing (Tierney and others, 1988). 

Kilijanek and Drabek (1979) describe early (1960's and 

1970's) studies of the elderly in disasters as inconsistent and 

contradictory. Yet researchers have found "a clear differential impact of disasters on the elderly" (Kilijanek and Drabek, 

1979, p. 565). For instance, the elderly keenly experience 

losses, such as of homes and possessions, on which they have 

labored (Bolin and Klenow, 1982). Poulshock and Cohen 

(1975) suggest that elderly who lose housing are more adversely affected thereby than younger victims. Other studies 

on disasters and the elderly look at how physical and mental 

health are affected (Melick and Logue, 1985; Norris and 

Murrel, 1988; Phifer and Norris, 1989; Phifer and others, 

1988) and suggest that elderly victims tend to cope well with 

disasters (Huerta and Horton, 1978). 

DISASTERS AND THE HOMELESS 

We know next to nothing about how disasters affect the 

homeless. General literature indicates that people become 

homeless because of increasing poverty and decreasing affordable housing. We know that a disaster such as an earthquake damages low-income housing, which is more likely to 

be precarious or substandard. Thus, we can anticipate that a 

strong earthquake such as Loma Prieta would decrease affordable housing. Homeless persons would consequently endure a longer wait to return to affordable housing. 

Wright (1988, 1989) describes a hidden group, the "marginally homeless" who live in doubled-up and tripled-up housing. An earthquake is likely to displace unforeseen numbers 

of these hidden homeless. The homeless are also a diverse 

group that range from families to individuals, from the physically disabled to the mentally ill (Wright, 1988). After a disaster, communities could face the problem of housing a heterogeneous group of previously and newly homeless who are 

difficult to relocate. 

FOUR PHASES OF SHELTERING AND HOUSING 

DISASTERS AND THE ELDERLY 

Elderly people typically lack affordable housing. One trend 

in elderly housing has been toward use of single-room-occupancy (SRO) hotels (Felton and others, 1981). SR07s are typically close to business sectors, are often deteriorating, and 

house tenants of low or fixed income. 

Researchers describe SRO residents as socially marginal. 

Social engagement varies from isolation to participation 

through internal, informal support systems. Elderly SRO residents are usually geographically distant from family members (Rollinson, 1990). They also commonly experience 

Quarantelli (1982a,b) identifies four phases of housing recovery: (1) emergency sheltering, (2) temporary sheltering, 

(3) temporary housing, and (4) permanent housing. Essentially, Quarantelli differentiates between these phases on the 

basis of their duration and the extent of established household routine. Sheltering phases are generally the shortest, ranging from a few hours of emergency sheltering to a few days 

of temporary sheltering. Housing phases involve establishing a household routine. The move from temporary sheltering to permanent housing can stretch from a few days to 

months or even years. 
SHELTERING AND HOUSING OF LOW INCOME AND MINORITY GROUPS IN SANTA CRUZ COUNTY 

Emergency sheltering is the first phase of recovery. Usually covered under Congressional mandate by the American 

Red Cross (ARC), emergency sheltering can last from a few 

hours to a few days. Temporary sheltering involves a longer 

duration, lasting as long as a few weeks. During temporary 

sheltering, displaced residents are still unable to assume normal household tasks or routines. 

Temporary housing involves the re-establishment of household routines. This phase is also indefinite, but can last from 

months to years. Families are able, however, to prepare meals 

and go about the regular business of family life. Temporary 

housing is a transitional stage in which the victims move from 

being provided for to providing for themselves. Finally, permanent housing is movement back into one's original, rebuilt 

domicile or into a new residence. This time, the move is of a 

lasting duration. 

HOUSING IN CALIFORNIA 

Two early 1980's studies of California housing focused on 

affordability and availability, yet reached different conclusions (Lowry and others, 1983; Rosen, 1984). In general, a 

state of flux characterized the 1970's California housing market. The average number of California households increased 

by a third, rents doubled, and home prices quadrupled. Nonetheless, housing production virtually stopped by 1980. Consequently, sales of existing homes declined dramatically. 

Despite this alarming scenario, Lowry and others (1983) 

did not believe a housing shortage existed. Likewise, they 

did not anticipate potential problems with overcrowding and 

substandard rental units except for recent Latin American 

immigrants, the elderly, and the poor in marginal rentals. 

Lowry concluded that California had an "exceptionally good 

housing inventory." 

Rosen (1984), on the other hand, came to a different 

conclusion. He predicted a crisis in housing availability by 

the mid-1980's. Rosen anticipated that low-income housing 

would be compromised because of strong demographic 

shifts, including immigration. A complicating factor would 

be the loss of housing units due to demolitions and natural 

disasters. Furthermore, Rosen found "in contrast to the 

Rand study [Lowry and others, 19831, that a significant 

number of California households face an affordability 

problem" (Rosen, 1984, p. 46). Additional constraints 

imposed by land-use controls (zoning, growth management 

systems, subdivision regulations, and environmental 

restrictions) would also hinder availability. Such constraints 

on the housing market would cause shortages and increased 

housing problems. 'Thus, in contrast to the Rand report, 

the growth in housing demand will be at about the same 

level as in the 1970's. This represents an enormous demand 

for shelter in California in the 1980's" (Rosen, 1984, p. 

29). It is quite likely, therefore, that low-income minority 

groups would face a dearth of affordable housing. A natural 

disaster would exacerbate the problem. 

METHODOLOGY 

This research was begun shortly after the Loma Prieta earthquake; field trips covered a 22-month period. Such longitudinal research is now a trend in the disaster research field 

(Drabek, 1986; Mileti, 1987). 

A long-standing methodological tradition in the field of 

disaster research is the use of interviews, observations, and 

systematic documentation (Quarantelli and Wilson, no date). 

That tradition was followed in this study. 

INTERVIEWS 

Several student assistants and I conducted the field research. 

Overall, we completed a total of 117 face-to-face interviews. 

An additional 8 respondents served as informants; that is, they 

gave information but did not participate in the full interview. 

Of the total interviews, 39 were follow-up interviews. We 

talked with representatives of 16 organizations on 2 separate 

occasions, with 12 organizations on 3 occasions, and 2 of the 

original 16 organizations on 4 occasions. 

We interviewed 72 separate individuals from 58 different 

organizations and offices. Our study ranged from local to 

external governmental units and from public organizations to 

private groups. Organizations ranged from local to regional 

to State to Federal entities. We included typical disaster response organizations such as the American Red Cross (ARC), 

Federal Emergency Management Agency (FEMA), local fire 

departments, and city and county emergency service departments. Our focus on housing meant that we also interviewed 

spokespersons of traditional housing organizations such as 

community housing coalitions, shelter services, and housing 

authorities. 

OBSERVATION 

To supplement our interviewing, we used a methodological triangulation strategy (Berg, 1989). That is, we used multiple methods to increase data richness and to improve validity and reliability. We conducted observations when 

opportunities became available, taking notes on the social 

structure and social processes involved in the events. As such, 

these observations are impressionistic and provide occasions 

for data checks, reflection, and the accumulation of anecdotal 

evidence. We made observations on 15 occasions, involving 

a variety of settings. For example, we observed public and 

private recovery meetings. 

SYSTEMATIC DOCUMENTATION 

Finally, we collected documents pertinent to this study. 

These documents included public disaster plans, internal reviews of the disaster plans, post-disaster plans for hazard 
D20 RECOVERY, MITIGATION, AND RECONSTRUCTION 

mitigation, internally developed disaster plans for a variety 

of organizations, recovery plans, memos, reports, and so forth. 

COMMUNITY CONTEXT 

The cities of Santa Cruz and Watsonville, though related 

through county affiliation, are decidedly disparate entities. 

Furthermore, the communities differ demographically, providing opportunities to study different groups and different 

cultures. 

SANTA CRUZ COUNTY AND CITY 

Santa Cruz County is located approximately 90 miles south 

of San Francisco, 40 miles south of San Jose, and 350 miles 

north of Los Angeles. The city of Santa Cruz lies between the 

Pacific Ocean (Monterey Bay), the San Lorenzo River, and 

the redwood forests of the Santa Cruz Mountains. Because of 

the rolling topography, there are several high and low points 

in the city. An alluvial flood plain next to the San Lorenzo 

River contains the downtown Santa Cruz area. In addition to 

flooding, disaster risks and experiences for Santa Cruz include landslides, severe storms, and earthquakes. 

In 1987, the population of the county was estimated at 

220,364; that of the city of Santa Cruz, at 46,921. According 

to the 1990 census, 229,734 resided in the county, with 49,040 

in Santa Cruz. Using either set of figures, the city of Santa 

Cruz constituted 21.3 percent of the county population. 

The predominant housing type in the city of Santa Cruz 

(63 percent) is the single-family unit. Most of these units (68 

percent) are owner occupied. Even though Santa Cruz employs 34 percent of the county work-force population, it only 

comprises 23 percent of the county's housing units. Because 

of the strong housing demand, vacancy rates remain very low 

(below 1.5 percent) in Santa Cruz, and housing costs are high. 

Typical monthly rental rates range from $500 to $750 for 

one- and two- bedroom apartments. Exceptions to such high 

rates were the SRO hotels that existed before the earthquake. 

The Palomar, a downtown SRO hotel, typically rented a room 

with private bath for $300 a month. The average estimated 

purchase price for single-family homes is $216,000 for a twobedroom home and $250,000 for a three-bedroom house. 

WATSONVILLE 

The city of Watsonville is an urban community that borders on rural farmlands. Its terrain is rolling to flat. Just inland from Monterey Bay and accessible off Highway 1, 

Watsonville is a small community close to several other communities, including the larger city of Santa Cruz. 

Before the 1989 earthquake, Watsonville had a population 

of 25,377, with a larger census count of 55,000 for the business area. By 1990, Watsonville's population had risen to 

3 1,099. Sixty-one percent of Watsonville's 1990 population 

was Latino. Watsonville's share of the county population was 

13 percent in 1987 and 13.5 percent in 1990. Latinos, the 

largest ethnic group in Watsonville, have an average household size of 4.05, with 36 percent of the households including more than five persons. 

Low-income families find it difficult to obtain housing, 

especially large rental units, in Watsonville. The price of 

homes, high rental prices, a high cost of living for the area, 

and a housing shortage all contributed to a pre-existing housing crisis in the area. This crisis appears to have worsened 

since the earthquake, with 3.12 percent of the rental market 

eliminated as of February 1990. The quake reduced overall 

housing by 8 percent. 

Not only is there a lack of affordable housing, but existing 

units are expensive. Sale prices of homes in Watsonville during 1988 ranged from $1 15,000 to $350,000, with a mean of 

$156,254. Rental units began at about $600 for a one-bedroom dwelling. 

Farmworkers have special problems finding affordable 

housing with enough space. Farmworkers make up 17 percent of the employed Watsonville population, and 26 percent 

of the area's Latinos are engaged in agricultural enterpri~es.~ 

Today's farmworkers are less transient than 15-20 years ago, 

implying increased need for housing. Watsonville officials 

indicate that farmworkers have had to resort to severe overcrowding to obtain shelter. Use of converted chicken coops, 

garages, and the like also occurs. Half of Watsonville and 

almost all special-needs households (elderly, low-income 

Latinos, farmworkers, and the homeless) lack income to afford adequate housing. 

EARTHQUAKE DAMAGE TO HOUSING 

SANTA CRUZ 

The earthquake created heavy damage to housing in downtown Santa Cruz; housing elsewhere in the area also suffered 

structural and fire damage. The most significant collective 

damage happened to the downtown SRO hotels. Each SRO 

hotel housed a mix of the elderly, transients, and low-income 

families and adults. Of the 4 SR07s hit by the earthquake, 

only the Palomar survived, and it did not reopen until summer 199 1. Years after the earthquake, inspectors throughout 

the county still uncover structural damage to houses and buildings. 

WATSONVILLE 

A February 1990 study by the Watsonville Commission 

Housing Task Force found that the earthquake had affected 

the rental market. Of 1,633 rental units, at least 51 became 

 his compares to 5 percent of the county population involved in 

farming. 
SHELTERING AND HOUSING OF LOW INCOME AND MINORITY GROUPS IN SANTA CRUZ COUNTY D2 1 

unavailable because of the earthquake. These represent 3.12 

percent of the rental market.2 In December 1989, Watsonville 

residents encountered a 1.4 percent vacancy rate (98.6 percent occupancy rate) in the city. Normally, such a situation is 

not a problem from the landlord's point of view. Low vacancy rates do, however, create housing problems for lowincome families. Building inspections also resulted in the loss 

of substandard housing such as converted garages and dilapidated buildings. 

OVERVIEW OF SHELTERING 

AND HOUSING 

This paper uses a framework identified by Quarantelli 

(1982a,b) to describe the process of sheltering and housing 

the earthquake victims. This section provides an overview of 

each phase: emergency and temporary sheltering, and temporary and permanent housing. Within each of the four phases, 

this paper looks at each community of Santa Cruz and 

Watsonville. The elderly and the already homeless are the 

focus in Santa Cruz, while low-income Latinos are described 

in Watsonville. 

EMERGENCY SHELTERING 

Emergency sheltering lasted from a few hours to a few 

weeks. Families and individuals camped out across the county 

for several nights after the earthquake. As expected, the American Red Cross (ARC) set up shelter facilities in numerous 

county location^.^ 

THE HOMELESS 

In Santa Cruz, local citizens perceive that two types of 

homeless exist. First, those who use shelters and (or) sometimes live on the streets are called the "homeless." Generally, 

public sympathy exists for them, especially for homeless families. The other type, "street people," create community concern, Street people are perceived by some as being responsible for street crime, for panhandling, and for chasing away 

tourism and business from the downtown Pacific Garden Mall 

 his is based on a 53.6 percent response rate to a Watsonville Planning Department Vacancy Survey, with an N of 1633. 

county estimates, based on Red Cross figures, indicate that 549 people 

used shelters the night of October 17. When rain began on Saturday, October 

21, shelter numbers rose to 2,545. The Red Cross opened 12 shelters in the 

south county (Watsonville area) and 9 in the northern part of the county 

(Santa Cruz). The Red Cross provided 38,295 shelter nights until December 

22, 1989. 

area. The street people were known to "hang out" downtown, 

and often engaged in panhandling. 

The earthquake physically dislocated both the homeless and 

the street people from the familiar downtown (the city fenced 

it off for safety purposes) and from pre-quake shelters for the 

homeless. Both street people and the homeless made their 

way to the Civic Auditorium, located about two blocks away 

from the downtown mall. The street people used this ARC 

shelter instead of established homeless shelters because a 

wider variety of services was available there. ARC shelters 

stayed open 24 hours a day and provided three meals a day. 

Pre-quake homeless shelters operated on a limited time basis, usually just overnight. Sometimes homeless shelters would 

serve breakfast or dinner. For some of the street people and 

the homeless, sleeping facilities before the quake meant camping in a community with a no-camping ordinance. Thus, being homeless then meant evading police enforcing the ban (it 

was not enforced for a while after the quake). 

ARC shelters, therefore, provided more comprehensive 

services to a pre-existing homeless population. Furthermore, 

the ARC made the decision to shelter everyone regardless of 

their pre-quake or post-quake homeless status. 

At the Santa Cruz Civic Auditorium the ARC sheltered a 

diverse group ranging from the elderly to families to street 

people. The variety of their lifestyles led to conflict between 

sheltered groups. For example, some shelter residents and 

police accused the street people of stealing and using drugs. 

Police officers arrested street people in the Civic Auditorium 

shelter (for drug dealing). However, natural forces unexpectedly alleviated the situation. Four days after the quake, steady 

rains fell and the shelter roof began to leak, causing the ARC 

to move the shelter to a church several miles away, across a 

highway. Few street people followed the shelter to the church; 

most remained near the familiar downtown. 

THE ELDERLY 

Many of the elderly from SRO hotels went to the Civic 

Auditorium for emergency shelter. The earthquake damaged 

all four downtown hotels; the city ultimately razed three out 

of the four. Other low-income elderly resided in trailers. 

Throughout the County, about 500 trailers shifted from their 

foundations. According to local social workers, most trailer 

victims stayed put rather than seek ARC shelter. 

Adult Protective Services, a program within the County's 

Human Resources Agency, became involved early with checking on elderly disaster victims and disabled adults. Overall, a 

high degree of concern and assistance for the elderly existed 

within and among elderly social services, and indeed throughout the community. 

ARC officials reported that senior citizens responded well 

to shelter life. Although the elderly experienced the earthquake as confusing and stressful, the local ARC met their 

shelter needs. 
D22 RECOVERY, MITIGATION, AND RECONSTRUCTION 

LOW-INCOME LATINOS4 

Despite the availability of several indoor ARC shelters, two 

parks served as emergency shelters for many Latino families 

in Watsonville. Tent-city encampments emerged at Callaghan 

and Ramsey Parks within 24 hours after the earthquake. Displaced residents were able to camp in these parks because of 

donations of camping equipment and other resources by individuals, the city of Watsonville, and the Salvation Army. A 

local Latino health organization, Salud Para La Gente (Salud) 

rendered medical assistance, helped the damaged and beleaguered Watsonville hospital, distributed blankets, and served 

as advocate for the newly homeless, predominantly Latinos. 

Debate developed over the outdoor camping. The city and 

ARC tried to persuade campers to move to indoor shelters. 

The ARC initially resisted declaring Ramsey Park, about 

five blocks from downtown Watsonville, an official "open air" 

shelter because the park lacked adequate sanitation, cooking, 

and refuse facilities. Local Latino leaders pressured the city 

and the ARC to open an official shelter. The county then asked 

the National Guard to erect tents in Ramsey Park. Four days 

after the earthquake, the Red Cross recognized Ramsey Park 

as an official shelter; however, rain soon transformed the 

campsite into a mudhole. Inadequate flooring, overcrowding, 

and lack of heat exacerbated the unpleasant shelter arrangements. Nevertheless, hundreds5 stayed on in Ramsey Park, 

with the numbers gradually diminishing until the camp closed 

on November 16, 1989. 

Callaghan Park, however, never became an official shelter, 

primarily because of a lack of appropriate amenities 

(restrooms, showers, and so forth). Between 100 and 300 victims continued to camp in Callaghan Park for several months. 

A few weeks after the quake, the ARC began to provide meals 

and nursing services in Callaghan Park. ARC personnel continued to urge Callaghan Park campers to move to an indoor 

facility or at least to Ramsey Park, but many refused. The site 

subsequently became a political focal point in the upcoming 

district elections for City Council. Local politicians seeking 

office in the district elections visited Callaghan Park to make 

~peeches.~ 

A number of factors explain why so many Latinos camped 

out in Watsonville. First, our respondents indicate that residents feared the effects of aftershocks-falling debris and 

crumbling homes. In addition, some confusion existed about 

building inspection tags. The problem stemmed mainly from 

466 Latinos" is used here instead of the more general term Hispanics. 

Our respondents consistently indicated a preference for the term "Latinos." 

'lt is difficult to obtain accurate numbers of those who camped in the 

parks. The Watsonville Red Cross did keep official records for their shelters, 

but only for the first few days. Because Ramsey Park did not open as an 

official shelter until Saturday, October 21, estimates must suffice. Journalists, ARC officials, and city representatives suggest the number of Ramsey 

Park campers alone ranged up to more than 500 per night during the first 

week after the earthquake. 

 h he district elections had been ordered by the U.S. Supreme Court 

following a lawsuit for a more ethnically representative city council. 

English-only tags that inspectors placed on homes. In addition, there was confusion about the meaning of the colors of 

tags. While most residents understood the use of red tags for 

"destroyed," and green tags for "safe to enter," they remained 

unsure about the meaning of yellow tags. 

The use of National Guard tents and personnel created another problem. The military appearance of Ramsey Park apparently generated fear in some Latino families. Some 

Callaghan Park campers refused to move to Ramsey Park for 

fear of encountering the military. Immigrants from Central 

American countries especially feared the National Guard presence. Experience with the military government in some Latin 

American countries meant arrest, imprisonment, or encounters with death squads. Others feared being reported to the 

Immigration and Naturalization Service. Despite assurances 

to the contrary on these matters, Callaghan Park campers refused to move to the official shelter in Ramsey Park. 

Finally, camping in parks or yards enabled victims to be 

close to their homes and to their children's schools. Thus, 

convenience, the presence of support networks, and fears 

about security kept people close to home and out of established shelters. 

Critics asserted that the southern county government and 

the ARC responded to Latinos with cultural insensitivity, exemplified by discouraging outdoor camping, providing inappropriate food, and lacking bilingual information. Watsonville 

city officials believed the earthquake beset the city with overwhelming demands, but they believed they responded with 

every effort manageable. As a result of the accusations, the 

Justice Department launched an inquiry but did not find any 

evidence of deliberate discrimination. However, the Department of Justice did suggest increased inclusion of Latino representatives in the ensuing recovery. Watsonville responded 

by bringing Latino representatives into recovery meetings, 

which eased the conflict. The city also appointed a part-time 

ombudsperson to link the Latino community with the city. 

These efforts marked the beginning of more inclusionary disaster response and recovery efforts, which continue today. 

Former adversaries now work cooperatively and closely together. 

TEMPORARY SHELTERING 

Emergency and temporary sheltering periods blended one 

into the other. Generally, the merging point occurred about 1 

or 2 weeks after the disaster. At that point, both official and 

unofficial shelters were fairly well established. However, the 

shelterees had not established household routines. The ARC 

and Salvation Army still met food, sanitation, and other basic 

needs. The temporary sheltering phase lasted from the end of 

October through December 1989. 

The elderly, Latinos, and some homeless people used hotels and motels for temporary shelter. Shortly after the earthquake, an ad hoc Housing Recovery Task Force (HRTF) was 

formed at the county level. The HRTF recommended using 

hotels for temporary sheltering purposes, since the end of the 

county's tourist season provided vacancies. 
SHELTERING AND HOUSING OF LOW INCOME AND MINORITY GROUPS IN SANTA CRUZ COUNTY D23 

The ARC provided funds for some victims to seek such 

temporary shelter in hotels, which is a standard procedure. 

The local Community Action Board (CAB) created a Motel 

Voucher Program. Funded by donations, the Motel Voucher 

Program enabled displaced victims to seek temporary shelter. Finally, the local Lodging Association worked cooperatively with the HRTF and ARC Motel Voucher Programs, offering motel rooms at reduced rates, for example. 

One final group assisting with both temporary shelter 

and temporary housing was an emergent, volunteer Housing Hotline, organized by community residents 2 weeks 

after the quake. People in need of housing or having housing with units available could call the hotline and be 

matched up. The hotline lasted until March 1990, when 

the CAB took over the hotline efforts. 

THE HOMELESS 

In Santa Cruz, a controversy arose early on as to whether 

people who were homeless before the earthquake deserved 

disaster-related sheltering and housing services. Although 

local officials felt sympathetic toward this homeless group, 

FEMA and the ARC chose to designate them as "pre-quake 

homeless" who were therefore not qualified for disaster aid. 

Local social workers insisted, though, that the earthquake 

considerably worsened the plight of those who became known 

as the "pre-quake" homeless. The temblor decreased low-income housing stock, thus increasing the difficulty for the 

homeless to locate affordable homes. In an already tight market for affordable housing, this left the homeless worse off 

than before. Regardless, the mostly non-local disaster relief 

organizations effectively blocked the pre-quake homeless from 

housing. Additional funding to the Motel Voucher Program 

stipulated that monies could only be designated for disaster 

victims (that is, not for the pre-quake homeless). 

THE ELDERLY 

The Santa Cruz community responded quickly to the plight 

of displaced elderly victims. Multiple organizations, including Senior Shared Housing, Adult Protective Services, and 

Elderday, an adult day-care center, participated in identifying housing options and relocating victims displaced from 

SRO hotels. Community volunteers helped remove belongings from the damaged SRO building^.^ 

Temporary sheltering for the elderly included ARC shelters; however, most elderly SRO-hotel victims moved on to 

temporary or permanent housing fairly quickly. This relatively 

rapid movement occurred because of numerous existing social service organizations for the elderly, which worked cooperatively to help the seniors. 

LOW-INCOME LATINOS 

The Santa Cruz County fairgrounds remained open until 

December 23,1989, as an ARC shelter, providing aid to families and single men. ARC officials believe this shelter, open 

for 66 days, was one of the longest operating shelters in U.S. 

history. The majority of the victims came from low socioeconomic status. Some were pre-quake homeless, nearly all of 

whom were from Santa Cruz County (despite rumors to the 

contrary). Most of the remaining shelter victims were Latino 

families and Latino adult men displaced because of the earthquake. Many of the fairground shelterees were relocated campers from Ramsey and Callaghan Parks. 

OVERVIEW OF EMERGENCY AND TEMPORARY 

SHELTERING PHASES 

To summarize, the elderly, low-income Latinos, and the 

pre-quake homeless all experienced physical dislocations from 

the impact of the earthquake. Initially, the local communities 

sheltered all the homeless regardless of their pre-quake or 

post-quake status. However, externally based funding organizations cut the pre-quake homeless out of temporary sheltering and housing opportunities. At this point, I wish to focus on how organizations responded to the elderly and to 

low-income Latinos. 

TEMPORARY HOUSING 

In January 1990 the Housing Recovery Task Force (HRTF) 

split into two committees, dealing with temporary and permanent housing, respectively. The HRTF had envisioned this 

division of labor from the beginning. Because the HRTF was 

an ad hoc, county-based coalition and some of the members 

were county employees, the separate work of temporary and 

permanent housing was passed on to appropriate agencies. 

The Short Term Housing Coalition began to operate out of 

Community Action Board (CAB)' offices and the Permanent 

Housing Committee came under the auspices of the Housing 

Authority. 

Movement into temporary housing began fairly quickly for 

some, mostly those from middle- and upper-income groups. 

These groups had more financial resources and insurance to 

provide for temporary housing. Movement was slower for 

the more numerous lower income victims. Housing officials 

 h he city allowed volunteers and elderly victims 15 minutes to remove 

their possessions. The 15-minute limit was implemented because of the possibility of dangerous aftershocks. 

'CAB had experience in working with homelessness and housing issues not related to disasters. 
D24 RECOVERY. MITIGATION, AND RECONSTRUCTION 

indicated that the majority of those needing help with temporary housing came from lower socioeconomic levels. Also, 

the earthquake damaged low-income housing disproportionately. 

Conflict over temporary housing developed between 

FEMA, the County, each city, and victims during this phase. 

Problems initially centered on the application process. FEMA 

had apparently used up most of its Spanish printed documents 

in Hurricane Hugo and had dispatched bilingual workers to 

affected Spanish-speaking islands, where they were still dealing with the hurricane's impact in September 1989. Therefore, FEMA responded to the quake with reduced supplies 

and personnel. 

FEMA did expend considerable effort and funds assisting 

the county, but problems lingered over serving Latino clients. For example, FEMA initially sent out checks and explanatory letters in English. Confusion and misunderstanding resulted. When FEMA did identify a household as Spanish 

speaking, though, FEMA sent subsequent letters in Spanish. 

As a result of problems like this, several northern California legal aid entities filed a lawsuit against FEMA in January 

1990. The lawsuit dealt with three issues: first, the legal entities filed to guarantee a right to a 60-day appeal period on 

FEMA denials. Second, legal aid filed suit to guarantee that 

all individuals and families would receive benefits, not just 

the person whose name appeared on the lease or came to the 

FEMA Disaster Assistance Centers first. This was necessary 

because pre-quake overcrowding in Santa Cruz County had 

caused many households to contain multiple families or unrelated adults. Finally, the legal entities sued for replacement 

of destroyed housing stock. FEMA originally settled out of 

court, but then did not take the agreed actions. Legal Aid therefore returned to court, and the court ruled in favor of the plaintiffs in April 1990. In December 1990, FEMA agreed to give 

nearly $6 million to rehabilitate low-income housing lost in 

the earthquake in Santa Cruz County. The entire settlement 

committed $24 million to San Francisco, Santa Cruz, and 

Alameda Counties. 

THE ELDERLY 

Caseworkers within the ARC, FEMA, Adult Protective 

Services, and seniors organizations actively helped elderly 

victims locate interim housing. The earthquake displaced more 

than 250 elderly from downtown SRO hotels. Some seniors 

left the county to live in less expensive housing. Some moved 

in temporarily with family, although this arrangement usually failed. Most of the elderly in these SRO hotels, as has 

been typical elsewhere, preferred to live alone. Additional 

arrangements made by some included moving to congregate 

care facilities or to small apartments. 

Some elderly held out for a return to the Palomar, the only 

remaining SRO hotel downtown. The loss of the other three 

downtown SRO hotels complicated the task of re-housing 

elderly victims. Elderly considered the downtown SRO hotels ideally located because they were close to grocery stores, 

a pharmacy, restaurants, shopping, and entertainment. Relocation threatened seniors' established links to needed services. 

The Housing Recovery Task Force (HRTF) developed ideas 

for temporary housing, including a failed FEMA-funded 

trailer court. One of the most successful efforts came through 

a non-profit group, Elderday of Food and Nutrition, Inc. 

Elderday suggested using a closed nursing home facility, 

called the Garden. Experienced in adult day care, Elderday 

offered to oversee operations of the Garden. FEMA paid for 

the expenses, and Elderday opened the Garden in January 

1990; however, meals were not included. About 25 seniors 

received temporary housing at the Garden. 

Moving the elderly out of the Garden proved challenging. 

Caseworkers from FEMA, the ARC, and Adult Protective 

Services assisted with the relocation. Garden residents reportedly preferred to hold out for a return to the downtown. Some 

advocates for the elderly believed the victims felt pressured 

to leave the Garden. The Garden closed in February 199 1. 

LOW-INCOME LATINOS 

The most open conflict between FEMA and local officials 

developed over the use of trailers as temporary housing. The 

HRTF believed trailers to be the best viable option for displaced Latino and elderly victims. FEMA disagreed, maintaining that adequate housing stock existed locally. The HRTF, 

local administrators, and politicians countered, citing a low 

vacancy rate and the lack of affordable housing. FEMA preferred not to use their mobile homes as temporary housing, 

given that the units were dated, not always up to code, and 

expensive to transport and set up. 

After considerable disagreement and politicization of the 

issue, FEMA capitulated in November 1989. FEMA moved 

122 trailers from Texas storage areas into Santa Cruz County, 

most of them onto temporary trailer park sites on public land 

in Watsonville (for example, at the county courthouse annex 

and the county fairgrounds). A few residents set up FEMA 

trailers on their private lots. 

The first residents moved into the mobile homes in December 1989. Over time, some families moved on to permanent housing with the help of a variety of caseworkers from 

FEMA, the ARC, and a locally funded Human Resources 

Agency Earthquake Trailer Park Project. Residents of the 

mobile homes were almost exclusively Latino, many with 

large families. Family size complicated the process of moving into permanent housing because of a scarcity of affordable units of adequate size. Discrimination against Latinos 

allegedly further impeded movement into permanent housing. Again, language barriers proved formidable. The Earthquake Trailer Park Project served as a conduit for translation, 

representation, and advocacy. 

Trailer families felt harassed by FEMA, who checked frequently on the status of the family's housing search. By the 
SHELTERING AND HOUSING OF LOW INCOME AND MINORITY GROUPS IN SANTA CRUZ COUNTY 

1-year anniversary, though, FEMA slowly began to move trailers out of the county. FEMA allowed families to buy the trailers, with prices based on the family's income. This provided, 

for some, the first opportunity in their lifetimes to become 

homeowners. Most trailer families lived in Watsonville on a 

permanent basis and a purchase symbolized increased security and stability. The potential purchase of the trailers fueled 

family resistance to moving. 

However, a lack of available trailer pads in Santa Cruz 

County increased the problems of purchasing trailers as a way 

of relocating into permanent housing. In addition to the cost 

of the trailer, purchasers had to pay for moving costs. Many 

families could not afford moving costs, which could be several thousand dollars. 

An emergent citizen group, the 17 Octubre Comite, composed of trailer park residents, formed in fall 1990 to advocate for purchase and relocation of the trailers. FEMA responded by continually pressing for relocation of residents to 

existing housing, fearing the families would be left homeless 

because of the lack of trailer pad sites. Eventually local and 

Federal officials agreed that trailer families would be best 

served by encouraging movement into available rentals. 

Through cooperative efforts, FEMA, the Earthquake Trailer 

Park Project, the city of Watsonville, and the Housing Authority relocated families from trailers into rental units. 

Buena Vista Migrant Camp, a summer residence for agricultural workers near Watsonville, also served as a temporary 

housing site from November 1989 through spring 1990. Operated by Housing and Community Development (HCD, a 

local organization), the camp usually closes in the winter because of sanitation problems. HCD, FEMA, and the city of 

Watsonville temporarily overcame these problems, but the 

location and facilities were not considered ideal. 

FEMA contributed significantly to the Santa Cmz County 

recovery. At the 1-year anniversary (October 17, 1990), 95 

coaches remained in Santa Cruz County as compared to 8 in 

Monterey County and 4 in San Benito County. Residents felt 

grateful for what they had received. Santa Cruz County received more aid for temporary housing than any other county, 

more than $1 1 million out of a total of $24.5 million, excluding mobile home costs.9 

THE ELDERLY 

Once again, caseworkers played a major role in moving 

seniors toward permanent housing. FEMA, the ARC, and 

Adult Protective Services all contributed ongoing case-management services. Social service organizations for the elderly also participated in this process, making referrals and 

setting some seniors up with shared housing arrangements. 

Adult Protective Services created a Placement Planning Group 

composed of relevant seniors' and disaster-relief organizations. The Placement Planning Group followed displaced 

SRO-hotel victims and fostered cooperation and communication between responding organizations. 

In addition to displacing residents of SRO hotels, the earthquake shook mobile homes owned by the elderly. An innovative program called Housing Assistance and Neighborhood 

Development (HAND), part of the county planning department, functioned to make damaged mobile homes usable. 

HAND served a clientele consisting mostly of elderly females. 

Part of the HAND program involved looking over contracts 

for reconstruction or repair in an attempt to reduce fraud 

against a vulnerable group. The HAND program, although 

limited in scope, served elderly women well. 

The County Housing Authority, which coordinated the Permanent Housing Committee, issued Housing and Urban Development (HUD) vouchers to qualified elderly residents. The 

Housing Authority made referrals and served as an advocate 

for Santa Cruz disaster housing needs. The Housing Authority also linked Federal relief efforts to the local level. 

Other efforts involved the transition into temporary housing. The Salvation Army exemplified a number of organizations that participated in helping victims to establish household routines, thus moving them into the latter recovery 

phases. SRO hotel residents, in particular, lost almost all 

household items. Non-profit groups, such as the Salvation 

Army, remained crucial in collecting and distributing household items ranging from appliances and furniture to household goods. 

LOW-INCOME LATINOS 

PERMANENT HOUSING 

Permanent housing was obtained by some displaced residents fairly quickly after the earthquake. For others, especially low-income families, this phase took considerable time 

and effort on the part of multiple organizations. Permanent 

housing represented a return to normalcy, the continuation of 

household routines in a lasting residence. 

'~ata obtained from the Federal Emergency Management Agency, the 

Presidio of San Francisco Office, October 1, 1990. 

Similarly, traditional groups like FEMA and the ARC assisted low-income Latinos to relocate into permanent housing. Caseworkers from the Watsonville Red Cross and the 

Santa Cruz County Human Resource Agency's Earthquake 

Trailer Park Project helped with referrals, served as advocates, and eased the transition to permanency. 

In both Watsonville and Santa Cruz, several Interfaith religious organizations worked for permanent housing, rendering aid with locating new premises, paying for deposits as 

well as first and last month's rent, financing small repairs, 

and rebuilding homes. Religious groups, like the Mennonite 

Disaster Service and the Christian World Relief Church Committee, worked with Watsonville Interfaith to completely rebuild homes. Habitat for Humanity also participated in the 

new construction. 
D26 RECOVERY, MITIGATION, AND RECONSTRUCTION 

AN OVERVIEW OF PERMANENT HOUSING 

By mid- 199 1, a multitude of public and private efforts enabled victims to begin recovering and rebuilding. Most programs centered on affordable housing for low-income victims. Earthquake donations partially funded construction of 

the Neary Lagoon Housing Project in Santa Cruz.1Â Earthquake victims receive some priority in relocating to Neary 

Lagoon. As of two years after the quake, local planning efforts continued and it became difficult to distinguish between 

what was replacement housing and what was simply the normal, ongoing housing construction process. 

SUMMARY 

In Santa Cmz County following the Loma Prieta earthquake, 

those hardest hit for the longest time period came from lowincome groups. Early on, relief organizations excluded the 

pre-quake homeless from assistance efforts. A variety of existing organizations worked to assist the displaced elderly 

toward permanent housing. A mixture of existing and emergent organizations helped low-income Latinos. More than 2 

years after the earthquake, work continued to provide for affordable permanent housing for low-income earthquake victims. 

CONCLUSION 

The data from Santa Cruz County clearly show that several 

factors created the sheltering and housing problems. It is 

equally apparent that solutions to these problems must address the conditions in a comprehensive fashion. I believe 

that pre-existing conditions, including a lack of affordable 

housing, a lack of cultural inclusivity, and a lack of integrated 

interorganizational planning, led to many of the sheltering 

and housing problems. 

AFFORDABLE HOUSING 

The most significant condition creating sheltering and housing problems in Santa Cruz County was a lack of affordable 

housing. This is not a unique problem across the nation even 

without disaster situations. Affordable housing declined precipitously in the 19807s, when the Federal government significantly reduced its role in such construction. Studies of 

homelessness generally point to this dearth of affordable housing as hastening the rise of homelessness (McChesney, 1990). 

Concomitantly, an increase in the poverty rate foreshadowed 

the rise of homelessness (Giamo, 1992; Lam and Wright, 

1987; Rossi and Wright, 1987; Wright, 1989). 

 h he Neary Lagoon Housing Project existed before the earthquake. 

The experiences of the cities of Santa Cmz and Watsonville 

with housing low-income and minority victims are quite likely 

representative of the problems to be encountered in future 

disasters. Previous research on the Whittier Narrows earthquake of 1987 warned us of this possibility (Bolton and others, 1992). Efforts aimed at mitigating housing problems in 

future disasters should necessarily include addressing the more 

generic concern of affordable housing across the Nation. A 

catastrophic New Madrid (Mississippi Valley) earthquake 

could have enormous repercussions, given today's rates of 

homelessness, hidden homelessness, and poverty. 

In summary, the solutions to potential housing problems in 

disasters lie in responding to existing problems of affordable 

housing, addressing the needs of a demographically diverse 

nation, and creating strong interorganizational communication and coordination. 

INCLUSIVITY AND DIVERSITY 

Demographic diversity also played a role in this disaster. 

First, disaster victims are heterogeneous. In addition, disaster effects do not strike randomly; socioeconomic status often determines who is affected most severely and who recovers most rapidly. In a society stratified on the bases of race, 

age, ethnicity, sex, and income, all aspects of sheltering and 

housing such a diverse group of people are affected. Community disaster response and recovery can be heightened by 

including diverse groups in the planning process and by anticipating both short-term and long-term sheltering and housing needs. Overlooking people and their problems is tantamount to increasing the effects of disaster (Haas and others, 

1977). 

Pre-quake conflicts and differences in community power 

affect sheltering and housing (Quarantelli 1982a,b; Bolin and 

Stanford, 1990). I found this to be true with the ethnic conflict in Watsonville and with the homeless controversy in Santa 

Cruz. Latino community representatives clearly felt excluded 

from the decisionmaking process. Since the earthquake, however, the city of Watsonville and Latino organizations have 

moved toward more cooperative disaster planning. This paradigm shift has healed some of the divisiveness, spurred recovery, and may serve as a mitigative factor in any future 

disasters. This is clearly an example of proactive, rather than 

reactive, mitigation policy (Drabek and others, 1983). 

Clearly, organizations like FEMA and ARC did not anticipate the extent of minority groups' needs in such an earthquake. Given previous experience with disasters such as the 

Whittier Narrows earthquake (Bolton, and others, 1992), these 

traditional disaster responding groups should have been better prepared. 

Our Nation continues to develop in demographically diverse ways. Addressing this demographic diversity in appropriate fashion, with involvement of members of the potentially affected groups, is essential. In the aftermath of the Loma 

Prieta earthquake, the ARC has taken a leadership role in re- 
SHELTERING AND HOUSING OF LOW INCOME AND MINORITY GROUPS IN SANTA CRUZ COUNTY 

spending to the needs of culturally diverse communities. The 

National ARC has created courses in cultural awareness and 

is looking closely at policy issues related to pre-existing 

homelessness. 

INTERORGANIZATIONAL COORDINATION AND 

COMMUNICATION 

Quarantelli (1982a,b) identified interorganizational coordination and communication as crucial to recovery. In Santa 

Cruz and Watsonville, local and nonlocal disaster relief organizations took a considerable time to develop a working rapport. Local groups and FEMA in particular experienced substantial conflict. This conflict affected organizations' abilities 

to respond to Loma Prieta quake victims. 

However, despite rancorous relations in the first 6 months 

after the earthquake, conflict decreased as FEMA and local 

residents and organizational representatives came to know 

each other. FEMA officials and local government workers 

were able to work together best after the initial 6 months, 

while interactions between FEMA and more ad hoc groups 

could best be described as chafing. The main lesson learned 

here is not a new one: key organizations need to talk before 

disaster strikes. 

Furthermore, it is useful to look beyond the emergency 

sheltering phase. Each community disaster plan studied in 

this research dealt only with the first phase following a disaster-emergency sheltering. Communities would be well advised to consider long-range plans for disaster housing 

recovery. Forging coalitions with existing nonprofit organizations may be a viable route toward such long-term planning. Studies of homelessness suggest that nonprofits are often well-suited to addressing the needs of temporary and 

permanent housing (Shinn and others, 1990). Additionally, 

homeless families typically need multiple services to be able 

to rise out of their predicament (Shinn and others, 1990). In 

Watsonville and Santa Cruz, caseworkers provided referrals, 

advocacy, translation, and other services. Multiple organizations gave out household items or funds for replacing goods. 

The process of arranging post-disaster housing involves more 

than the reconstruction or rehabilitation of dwelling units. 

In summary, pre-existing conditions can greatly hinder or 

facilitate the return of low-income and minority groups to 

permanent housing after a disaster. This is not a new finding. 

However, given the national increase in homelessness, poverty, and demographic diversity, in combination with the decline of affordable housing, such post-disaster housing crises 

undoubtedly will be seen again. Clearly, viable solutions to 

post-disaster housing problems lie in addressing pre-existing 

social problems of housing, inclusiveness, and planning. Essentially, communities need to be prepared to reconstruct 

housing before disaster strikes (Haas and others, 1977). Disaster recovery can best be understood and facilitated through 

understanding the larger social context within which housing 

problems arise. 

ACKNOWLEDGMENTS 

This paper is a revision of an earlier paper presented to the 

California Seismic Safety Commission. The research was 

funded jointly by the National Science Foundation1U.S. Geological Survey BCS-9003886. Research assistants on the 

project were Lisa Rodriguez, Laura Watt, and Melinda 

Ephraim. Thanks go also to Joanne Nigg and Peter H. Stauffer. 

The author retains sole responsibility for the content and views 

expressed here. 

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Berg, B.L., 1989, Qualitative research methods in the social sciences: Boston, Allyn and Bacon. 

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Bolin, R.C., and Bolton, Patricia, 1986, Race, religion, and ethnicity 

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Bolin, R.C., and Klenow, D.J., 1982, Response of the elderly to disaster-an age-stratified analysis: Aging and Human Development, v. 16, no. 4, p. 283-296. 

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Bolton, Patricia, Liebow, E.B., and Olson, J.L., 1992, Community 

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Drabek, Thomas, 1986, Human response systems to Disaster-an 

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Drabek, T.E., Mushkatel, A.H., and Kilijanek, T.S., 1983, Earthquake mitigation policy-the experience of two states: Institute of Behavioral Science, University of Colorado, Monograph 

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Felton, B .J., Lehmann, Stanley, and Adler, Arlene, 198 1, Single room 

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267-285. 

Giamo, Benedict, 1992, Making dust-the symbolic landscape of 

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Haas, J.E., Kates, R.W. and Bowden, M.J., 1977, Reconstruction 

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D28 RECOVERY, MITIGATION, AND RECONSTRUCTION 

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Melich, M.E., and Logue, J.N., 1985, The effect of disaster on the 

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THE LOMA PRIETA, CALIFORNIA, EARTHQUAKE OF OCTOBER 17,1989: 

SOCIETAL RESPONSE 

RECOVERY, MITIGATION, AND RECONSTRUCTION 

HAZARDS MITIGATION AND HOUSING RECOVERYWATSONVILLE AND SAN FRANCISCO ONE YEAR LATER 

By Mary C. Comerio, 

University of California, Berkeley 

CONTENTS Page 

Abstract ......................................................................... D29 

Introduction ................................................................... 29 

Building hazards mitigation .......................................... 29 

Damage from the Loma Prieta earthquake ................... 30 

San Francisco ....................................................... 3 1 

Watsonville. .......................................................... 3 1 

The components of recovery ......................................... 3 1 

Incentive ............................................................... 32 

Technology.. ......................................................... 32 

Financing .............................................................. 32 

Regulation ............................................................ 32 

Available space ..................................................... 32 

Self help.. .............................................................. 32 

Lessons-One Year Later .............................................. 33 

Lesson 1: Use local resources, 

human and financial ........................................ 33 

Lesson 2: Balance safety and social needs ........... 33 

Lesson 3: Integrate technical, social, and 

financial analyses in local programs ............... 33 

Conclusion ..................................................................... 33 

References ..................................................................... 34 

ABSTRACT 

The City of Watsonville lost 642 housing units in the 1989 

Loma Prieta earthquake. These were primarily small singlefamily dwellings that were knocked off their foundations. In 

less than one year, 75 percent were repaired or replaced. In 

San Francisco, 500 of the 1,482 red-tagged (severely damaged) units were demolished, and a total of 36,000 units were 

damaged. After one year none of the large brick buildings 

had been repaired, none of the units torn down had been replaced, and only 50 percent of the wood-frame buildings damaged had begun repair work. It is unfair and unrealistic to 

compare the housing recovery rate of single-family dwellings in a small-town setting to the replacement of multifamily units in a large city. However, it is valuable to examine 

what was and was not working in each locale as it pertains to 

housing issues and hazard mitigation. The factors that made 

the Watsonville and San Francisco experiences so different 

were the availability of financing, the incentive to rebuild, 

and the local construction capacity. 

INTRODUCTION 

The Loma Prieta earthquake in 1989 rocked the Bay Area 

for 15 seconds. In that brief period, a portion of the San Francisco-Oakland Bay Bridge and a three-quarter-mile section 

of the Nimitz Freeway collapsed and a large number of buildings sustained significant damage in the cities of Watsonville 

and Santa Cruz, in the Marina and South of Market Districts 

of San Francisco, and in downtown Oakland. Perhaps the most 

important lesson from the Loma Prieta earthquake was the 

vulnerability of structures built on fill and soft soils. As with 

any disaster, however, there are numerous lessons to be drawn 

on many topics, ranging from preparedness through mitigation, engineering, prediction, and response. 

This paper will focus specific attention on housing, not only 

because so many people were directly affected by damage and 

loss, but also because the problems of recovery and reconstruction are related to the problems of pre-earthquake hazard 

mitigation. San Francisco and Watsonville represent the spectrum of housing issues affecting large metropolitan areas and 

small rural towns. The experience of these two communities 

suggests that the rate of reconstruction of the housing stock 

depends on several local factors-incentive, technology, financing, regulation, available space, self help, and luck. 

BUILDING HAZARDS MITIGATION 

Significant programs for hazards mitigation in existing 

buildings are relatively new in California. Since the early 

D29 
D30 RECOVERY. MITIGATION, AND RECONSTRUCTION 

1980'~~ local jurisdictions have begun the task of identifying 

potentially hazardous building types, and the engineering 

community has worked to develop techniques for improving 

building performance for life safety and damage control. 

During this period, engineers and emergency preparedness 

groups have also taken steps to develop a public consciousness regarding earthquake hazards and have lobbied for building codes that require retroactive repair of unreinforced masonry and tilt-up industrial buildings. In fact, very few cities 

had mitigation programs in place before October 1989. 

Although the cities of Long Beach and Santa Rosa have 

had "active"l ordinances since the 19707s, it was the enactment of the Earthquake Hazards Reduction Ordinance (commonly known as "Division 88", its numerical section of the 

local building code) in Los Angeles in 198 1 that helped focus 

statewide attention on the retrofit of existing unreinforced 

masonry buildings (known commonly as URM's). This ordinance established a set of priorities for retrofit of the city's 

8,000 URM's. Emergency facilities, such as hospitals, police 

stations and fire stations, were the first to receive citations 

from the building department. Next in line were buildings 

defined as high risk, including churches, theaters, offices, and 

other public assembly buildings. Schools, which are regulated through State agencies, are not included in local building regulations. Buildings of medium and low risk (housing 

and industrial structures with relatively low occupancies) were 

to be cited last. The entire program was designed to be implemented over a period of 15 years. 

In 1985, the severe damage in Mexico City from the 

Michoacan earthquake prompted Los Angeles City Council 

members to accelerate the program and require completion 

of all retrofit by 1991. This happened at the point when the 

city was just beginning Ihe citation process for medium- and 

low-risk buildings, including 1,582 residential buildings containing 46,000 housing units. To meet the new schedule established by the Council, all citations were issued by December of 1986, all permits should have been secured in 18 months 

(by June of 1988), and all construction should have started 

within 2 years (by December of 1988). The fast-track mitigation program proved to be an unrealistic goal. As of October 

1990, only 25 percent of the buildings cited in 1986 had actually completed construction, approximately 40 percent were 

in progress, 25 percent made no progress towards construction, and 10 percent were demolished. These figures on 

completion of seismic retrofits in Los Angeles were calculated by the Community Development Department (based on 

Building and Safety computer records) in October 1990 for a 

status report to the City Council. By 1991, more rehabilitations were in progress, but no more had been completed 

(Comerio, 1992). 

~ctive ordinances target specific buildings, classes of buildings or 

elements of buildings and require specific action to be taken. By comparison 

passive abatement programs re'quire hazard reduction only when a predefined 

action, such as a change of use or major renovation, is taken by the owner. 

While the implementation problems with the Los Angeles 

ordinance are the subject of other papers (Comerio, 1990, 

1992), the completion rates for the housing are important to 

note here because most California cities look to the Los Angeles plan as a model both for engineering requirements and 

for implementation methods. In 1986, at the same time that 

Los Angeles was trying to speed up its compliance schedule, 

the State passed a law requiring all local jurisdictions to inventory their hazardous building stock and develop plans for 

mitigation. This law, Senate Bill 547, did not go so far as to 

provide funding, nor did it require cities to implement retrofit ordinances, but it did put cities on notice that they were 

responsible for thinking about how to handle this problem. 

The 1987 Whittier Narrows earthquake provided the first 

small test of the Los Angeles retrofit program. Although it 

was only a moderate earthquake (magnitude 5.9), it did provide the opportunity to review strengthening procedures and 

renew the political pressure for State and local mitigation 

programs. Unfortunately, the 1989 Loma Prieta earthquake 

preceded the adoption of most such programs. On the positive side, this magnitude 7.1 quake did provide a good preview of the kind of damage the Bay Area might expect in 

future earthquakes of similar magnitude. "Preview" is the 

appropriate term because it is generally agreed that the 

earthquake's short duration (15 seconds) and the location of 

its epicenter (60 miles south of San Francisco in the Santa 

Cruz Mountains) spared Bay Area cities from more significant damage. 

DAMAGE FROM THE LOMA PRIETA 

EARTHQUAKE 

Although the media focused public attention on the collapsed portions of the Bay Bridge and the Nimitz Freeway 

and on the damage in San Francisco's Marina District, this 

was not the whole story. There was extensive damage to older 

buildings throughout San Francisco and Oakland. In San Francisco, 71 percent of all buildings damaged were residential. 

While this residential loss represents only a tiny portion (1.5 

percent) of the city's total housing stock, 60 percent of the 

nearly 36,000 units damaged housed people of low and moderate income. Nearer to the epicenter, the cities of Santa Cruz 

and Watsonville each lost 60 percent of their downtown commercial districts. Furthermore, Watsonville lost 8 percent of 

its housing stock, while 76 percent of that city's total occupied housing was damaged (damage figures from Bureau of 

the Census, 1983, and internal reports by the cities of 

Watsonville and San Francisco). 

For all the cities in the Bay Area affected by the Loma 

Prieta earthquake, recovery and mitigation are now two sides 

of the same coin. For San Francisco and Watsonville, housing (particularly affordable housing) is a critical issue, and 

the experience one year after the quake should help us to understand the opportunities and the stumbling blocks for both 

recovery and mitigation. 

D32 RECOVERY, MITIGATION, AND RECONSTRUCTION 

part, it is unfair to compare single-family wood frame buildings of 1,000-2,000 square feet to large multistory, multiunit 

buildings. It is valuable;, however, to examine what did and 

did not work in each locale and why. Specific local conditions significantly affected the rate of reconstruction. 

In Watsonville, the city simply gave away $1 million in 

grants of $20,000 to $50,000 to individuals who wanted to 

repair their houses but could not qualify for conventional financing. Although the grants represented only 5 percent of 

the estimated $20 million repair bill, these funds clearly expedited the recovery process. 

INCENTIVE 

REGULATION 

In Watsonville, 40 percent of the houses were owner occupied and the remainder were owned either by an owner-occupant next door or by another town resident. In San Francisco, 

the great majority of the buildings were owned by absentee 

owners. There is a real difference in incentive, motivation, 

and energy between an owner anxious to replace his or her 

own home and an investor evaluating the financial merits of 

rebuilding a rental property in the current real estate market. 

The owners of single-family homes in Watsonville were 

clearly motivated to rebuild and restore their lives, whereas 

many owners of multifamily apartment houses in San Francisco faced high building renovation costs in neighborhoods 

where rents were low and housing was considered a bad investment. 

As in all large cities, construction projects in San Francisco must go through a myriad of planning and building reviews before permits can be issued. Even after an earthquake, 

there is a limited amount a large city can do to circumvent its 

own procedures once the immediate emergency has abated. 

In a smaller community like Watsonville, there is an opportunity for city staff to redefine the regulatory process. In the 

1989 crisis Watsonville decided to be easy on permits and 

tough on inspections. In a city where the Planning Director 

knew most residents by name and the task of repair was relatively straightforward, the city was able to avoid time delays 

by placing the burden of control on the building inspectors in 

the field. 

AVAILABLE SPACE 

TECHNOLOGY 

As stated earlier, there is no comparison between small, 

single-family wood frame houses and multiunit apartment 

buildings. While appropriate building materials were generally available in both areas, the former type of structure requires minimal tools and skills while the latter requires engineering and architectural drawings as well as licensed, 

experienced professional contractors. The fact that single-farnily houses can be renovated by small contractors and owner 

builders with assistance from unskilled labor contributed to 

the speed of housing recovery in Watsonville. Large apartment buildings cannot be done in the same ad hoc fashion. 

Their reconstruction requires adherence to the standards set 

by design professionals, financial institutions, and city regulators. 

FINANCING 

In San Francisco, the Mayor's Office of Housing estimated 

a need for $11 8 million (at $80,000 per unit) to replace redtagged units and $96 million (at $20,000 per unit) to repair 

yellow-tagged units. Remembering that 60 percent of the units 

lost or damaged were providing affordable housing to tenants of low and moderate income, the scale of the public subsidy necessary to retain some of those units for low- and 

moderate- income renters is daunting. Furthermore, it is unclear whether buildings in marginal areas such as the South 

of Market and Tenderloin Districts could obtain private financing for replacement housing. 

In San Francisco there were two very different kinds of 

tenants and two very different sets of choices. White middle 

class tenants who lost apartments in the Marina and other 

outlying districts simply moved to vacant units in other neighborhoods. Landlords offered them breaks on rent and deposits; department stores often offered furniture at cost. For nonEnglish-speaking, low-income, elderly, and transient tenants 

in the South of Market, there were few opportunities outside 

the emergency shelters and city-sponsored homeless shelters. 

Community groups provided some assistance but could not 

rehouse those displaced in an already overcrowded and 

undersupplied market. 

In Watsonville there was also a limited supply of vacant 

space to accommodate people and businesses on a temporary 

basis, and it was clear that even the strong extended family 

networks could not satisfy the need for temporary housing. 

Mobile homes were brought in by the Federal Emergency 

Management Agency, despite the agency's original reluctance, 

in order to keep people close to their jobs and the homes they 

hoped to rebuild. 

SELF HELP 

In San Francisco, middle class tenants generally accommodated the loss of housing and personal possessions while 

maintaining their jobs, but low-income people had a more 

difficult time. Displaced tenants in the South of Market District joined the ranks of the homeless, waiting for public assistance. 
HAZARDS MITIGATION AND HOUSING RECOVERY-WATSONVILLE AND SAN FRANCISCO D33 

In Watsonville, cannery workers and farm laborers did not 

lose their jobs, because there was no damage to these industries. These families traditionally rely on themselves and their 

neighbors, and they simply worked with the local construction labor force to rebuild their homes. Retirees and church 

groups pitched in and organized volunteer labor and "houseraising" parties to assist individual families. Such efforts reduced the real costs of construction and built a strong community spirit. 

LESSONS-ONE YEAR LATER 

On all the points described above, San Francisco was a 

victim of scale. The loss of so many affordable units in a city 

with a housing vacancy rate of less than 1 percent is a significant blow, not only to the tenants, but to the city already struggling to maintain an adequate supply of affordable housing. 

Despite strong public leadership, neither the city nor private 

owners were able to fund the reconstruction, and State and 

Federal assistance would be too little and too late. Watsonville, 

by contrast, managed to overcome a potentially devastating 

loss of affordable housing units. The community exhibited 

very sensible leadership, targeted critical financing, and was 

blessed with a strong dose of luck, in that local jobs were not 

lost, and volunteers from charitable organizations supplied 

rebuilding assistance to local homeowners. 

Other communities cannot guarantee the component of luck, 

but they can develop the leadership and the creativity to take 

advantage of local opportunities. In planning for future disasters, several lessons can be drawn from the experiences of 

Watsonville and San Francisco following the Loma Prieta 

earthquake. 

LESSON 1: USE LOCAL RESOURCES, HUMAN 

AND FINANCIAL 

The recovery program that worked for Watsonville took 

advantage of local people's vested interest in restoring their 

own houses. They took what was available and made the best 

of it. Had they decided to wait for larger loans or better deals, 

they might still be waiting. Although each individual house 

might not reach a level of finish that others would expect, 

shelter was more important than community architectural standards. 

In San Francisco, the losses from the Loma Prieta earthquake have made the nonprofit community housing organizations recognize the importance of mitigation. These groups 

have asked the city for training from local engineers so that 

they could serve as technical inspectors and advisors on their 

own projects and in their neighborhoods. It was these same 

groups who began to include seismic upgrading in their lowand moderate-income renovation projects before it became a 

city requirement. 

LESSON 2: BALANCE SAFETY AND SOCIAL 

NEEDS 

San Francisco has been criticized for its slow process in 

developing a retrofit ordinance and criticized further for opposing a State model code. However, it is clear from the descriptions of conditions in only two cities that it would be 

impractical to impose a single technical standard on hazardous building types in all locations. This is not an argument 

for applying a lower standard to housing than to commercial 

buildings. Instead it is a recognition that the unique problems 

facing residents in the Chinatown, Tenderloin, and South of 

Market neighborhoods in San Francisco ought to be dealt with 

by San Franciscans who can shape a hazards abatement program to local circumstances. 

Each community needs to analyze its own housing inventory and develop specific hazard-abatement strategies and 

methods that meet their own conditions. In some cases, a landuse decision to limit building on fill may be more useful than 

renovating a particular class of building. 

LESSON 3: INTEGRATE TECHNICAL, SOCIAL, 

AND FINANCIAL ANALYSES IN LOCAL 

PROGRAMS 

The main problem with locally based research is that most 

large-scale aid organizations do not want to accept local solutions. However, all good local solutions to specific problems, such as housing production or hazards mitigation, can 

be understood in terms of local application of general principles. Watsonville distributed funds quickly, made individuals responsible for their own construction, provided technical assistance, and stayed out of the way. How they did this 

was unique to Watsonville, but what they did could apply to 

any small-scale locale with extensive loss of housing and a 

minimal loss of jobs. 

The arguments that favor local initiative and local control 

may appear to suggest that disaster assistance and hazard 

mitigation should be taken off the public agenda. That is not 

the intention. There is a very real need to maintain and improve our building stock over the long term. Natural hazards 

remind us of the need to renovate and extend the useful life 

of the existing housing stock through mitigation and recovery. 

With some irony, Watsonville City officials express a certain thankfulness to the earthquake. It gave them the opportunity to rebuild and improve a large segment of very old and 

ill-maintained housing with donated funds, thus keeping it 

affordable to moderate income families who will be part of 

the community for a long time to come. 

CONCLUSION 

The final lesson from the experiences of both Watsonville 

and San Francisco is that housing is a precious commodity, 
D34 RECOVERY, MITIGATION, AND RECONSTRUCTION 

and both mitigation and recovery are a matter of public choice. 

In Watsonville, the city chose to spend limited public funds 

on private property, while the community contributed expertise and labor to assist lo~w-income families in rebuilding their 

homes. Because fully 75 percent of the housing stock sustained some damage, city inspectors used this opportunity to 

advise residents to ensure that houses were bolted to foundations, water heaters strapped, chimneys tied, and other obvious hazards mitigated to prevent similar losses in the next 

earthquake. 

In San Francisco, the total cost of preventive strengthening 

for the undamaged housing stock could be twice that of the 

Loma Prieta earthquake's repair bill, even though the cost 

per unit for mitigation is only about 10 percent of the cost of 

a replacement housing unit (Rutherford and Chekene, 1990). 

No large city can depend on donations, self help, and good 

neighboring alone to preserve the existing building stock. 

Recovery and mitigation will be slow processes involving 

significant commitments of public funds and public will. 

Large cities, however, are similar to small towns in that there 

is a need to understand the physical conditions of their existing building stock and the social and economic conditions of 

their inhabitants to develop realistic and implementable programs. If there is any doubt about the importance of developing such programs, we have only to look at the numbers of 

housing units affected in the Loma Prieta earthquake and consider the potential for housing loss in the next earthquake in 

an urban area. 

REFERENCES 

Bureau of the Census, 1983, City and county date book: Washington, D.C., U.S. Department of Commerce, Bureau of the Census. 

City and County of San Francisco, 1989, Earthquake impact on lowand moderate-income housing: San Francisco Mayor's Office 

of Housing, Report no. 4, November 20. 

Comerio, M.C., 1987, Earthquake hazards and housing: report prepared for the City and County of San Francisco, Department of 

City Planning, v. 1, 176 p. 

Comerio, M.C., 1990, Seismic safety-at what price?: Proceedings 

of the Fourth National Earthquake Engineering Conference, 

Palm Springs, California, v. 1, p. 201-218. 

Comerio, M.C., 1992, Impacts of the Los Angeles retrofit ordinance 

on residential buildings: Earthquake Spectra, v. 8, no. 1, p. 79- 

94. 

Rutherford and Chekene, 1990, Seismic retrofitting alternatives for 

San Francisco's unreinforced masonry buildings-estimates of 

construction cost and seismic damage: report prepared by Rutherford and Chekene, Consulting Engineers, for the City and 

County of San Francisco, Department of City Planning. 
THE LOMA PRIETA, CALIFORNIA, EARTHQUAKE OF OCTOBER 17,1989: 

SOCIETAL RESPONSE 

RECOVERY, MITIGATION, AND RECONSTRUCTION 

LOCAL EARTHQUAKE MITIGATION PROGRAMS-PERCEPTIONS OF 

THEIR EFFECTIVENESS FOLLOWING THE LOMA PRIETA EARTHQUAKE 

By Patricia A. Bolton and Carlyn E. Orians 

Battelle Seattle Research Center, Seattle, Wash. 

CONTENTS Page 

Abstract ......................................................................... 035 

Introduction.. ................................................................. Examining Mitigation ................................................... Institutional location of local responsibility 

for mitigation .................................................. Local understanding of vulnerability ................... Explanations of damage averted ................................... The Loma Prieta earthquake as a catalyst 

for subsequent mitigation efforts .............................. Existing buildings ................................................ Seismic safety elements and 

land-use ordinances ......................................... Outreach, education, and other activities ............ Significant Changes Related to 

the Loma Prieta Earthquake ............................ Usefulness of technical assistance sources ................... Most familiar sources .......................................... 

Most helpful sources ............................................ Implications for the enhancement of 

technical assistance ......................................... Summary and conclusions ............................................. Acknowledgments.. ....................................................... References Cited ........................................................... 

ABSTRACT 

Federal, state, and regional programs promoting local-level 

mitigation activities to reduce losses and disruption from 

earthquakes have been carried out in past years. The Loma 

Prieta earthquake provided a test of these measures in many 

jurisdictions and offered an opportunity to examine if local 

agency staff now view their loss-reduction strategy as effective. Respondents from city and county agencies in the affected region were asked, through a combination of personal 

interviews and a mail-in questionnaire, if they believed their 

mitigation efforts had averted damage, what new mitigation 

measures or plans were being initiated in their jurisdiction 

since the earthquake, and what information sources and technical assistance they have found most useful. The responses 

suggest that (1) well-enforced local building codes are viewed 

as effective in reducing or eliminating damage and, in these 

California communities, are the primary means for mitigating damage; (2) programs aimed at promoting simpler, lower 

cost measures for strengthening existing buildings or minimizing nonstructural hazards should be more aggressively 

pursued; (3) sources of information and technical assistance 

that are easily accessible and locally relevant, and those provided by credible sources such as other members of their own 

profession, are viewed as most useful; and (4) Federal, state, 

and regional programs that provide assistance to local jurisdictions should be cognizant of the variety of organizational 

structures within governments, so that vital information 

reaches the appropriate offices or individuals. 

INTRODUCTION 

Since the passage of the National Earthquake Hazards 

Reduction Act in 1977 (Public Law 95-123), the Federal 

Government has taken the lead in developing earthquake 

safety policy and program goals. The National Earthquake 

Hazard Reduction Program (NEHRP) has supported a 

variety of efforts related to the promotion of earthquake loss 

reduction at the local level across the Nation (see, for 

example, Federal Emergency Management Agency, 1984, 

1988). Federal policy focuses on state and local governments 

as the appropriate levels of implementation for earthquake 

preparedness programs. States may shape local policy by 

mandating that certain practices be consistent with state 

policy. However, for the most part, earthquake preparedness 

and loss reduction practices must be implemented at the local 

level. Local jurisdictions have been mandated, exhorted, and 

assisted in a variety of ways to develop programs designed 

to reduce the vulnerability of their residents, buildings, and 

lifelines to earthquake damage. 
D36 RECOVERY, MITIGATION, AND RECONSTRUCTION 

Technical studies that have been conducted to evaluate specific mitigation techniques include laboratory and field studies of specific techniques, systematic reviews of the performance of specific types of buildings, and post-earthquake 

investigations to identify factors that contributed to damage 

in specific buildings. Evaluations such as these address the 

theoretical effectiveness of techniques designed to reduce or 

prevent damage (May and Bolton, 1986). That is, they address the ability of specific measures to reduce damage, where 

correctly applied, or, conversely, the likelihood that observed 

damage could have been avoided had specific measures been 

implemented. Much of the available technical assistance on 

how to carry out specific mitigation measures is based on 

such studies. Each successive earthquake provides new insights into what does and does not work under certain circumstances. However, any given loss-reduction approach, no 

matter how theoretically effective, only works to the extent 

that it is applied. 

A particular challenge is posed by structures constructed 

before advances in understanding of the seismic hazard and 

of effective means of mitigating or lessening their vulnerability to the hazard. Unfortunately, knowledge that has been 

gained is often not systematically applied because of formidable economic and political barriers (Alesch and Petak, 1986; 

Berke and Wilhite, 1988; Drabek and others, 1983). Of all 

the states with a recognized earthquake hazard, California 

has, despite such barriers, without question engaged in the 

greatest amount of earthquake mitigation planning at both 

the state and local levels (Berke and Wilhite, 1988). 

The mainshock of the Loma Prieta earthquake was felt over 

much of central and northern California. Many jurisdictions 

in this region experienced ground shaking of a sufficient intensity (Modified Mercalli intensity VII to IX) to test the effectiveness of their building standards and other earthquake 

mitigation practices. Even though the Loma Prieta earthquake 

resulted in approximately $8 billion in damage to structures 

and other direct costs (California Seismic Safety Commission, 1991), most of the development in the San Francisco 

Bay region in fact survived the earthquake with little or no 

damage. 

Although jurisdictions in the region that experienced lower 

ground shaking intensities (Modified Mercalli intensity VI 

or lower) may have escaped significant damage from the Loma 

Prieta earthquake, recent probabilistic forecasts along the same 

fault and along other active faults identified in the region indicate that many are at risk from future major earthquakes 

(Real, 1984; Working Group on California Earthquake Probabilities, 1990). These j~urisdictions will benefit from reexamining their own actions in light of damage patterns in the 

harder hit areas. Similarly, the rest of the Nation at risk from 

major earthquakes should take note of the lessons of the Loma 

Prieta quake regarding the sources of seismic damage and 

seismic safety. 

Even in California, few jurisdictions have anything that 

could be called an aggressive and comprehensive mitigation 

strategy (Berke and Wilhite, 1988, p. 33-35). However, the 

use of the Uniform Building Code (UBC) is mandated by the 

State, and many examples of local-level earthquake hazard 

mitigation programs can be found in the region (see, for example, Bay Area Earthquake Study, 1984; Beatley and Berke, 

1990; Blair-Tyler and Gregory, 1988; Federal Emergency 

Management Agency, 1990, p.61-69; Mader, 1988). The Loma 

Prieta earthquake provided an opportunity to examine (1) how 

well some of these local efforts at earthquake hazard mitigation fared, (2) whether the consequences of the earthquake 

have led local jurisdictions in the region to reevaluate local 

efforts aimed at earthquake hazard mitigation, and (3) which 

of the various types of hazard information and mitigation program guidance have been useful to local building officials and 

planners. The study focused on county and city mitigation efforts in the seven counties that sustained the most damage as a 

result of the earthquake: Alameda, Contra Costa, Marin, San 

Mateo, Santa Clara, Santa Cruz, and San Francisco Counties. 

The level of damage experienced in these counties varied 

considerably, from virtually no damage to structures, to severe localized damage of a specific structure, type of structure, or type of site. Data on mitigation activities were collected principally from interviews with agency officials and 

from a questionnaire sent to county and city departments most 

likely to be involved in hazard mitigation activities. Beginning approximately 18 months after the Loma Prieta earthquake, 30 personal interviews were conducted in 13 cities 

and counties with various county and city officials, and 4 similar interviews were conducted with Federal, California State, 

and regional program representatives. Based on these initial 

conversations, a questionnaire was mailed to each of two departments in 39 different jurisdictions. One or both departments from 24 of these jurisdictions provided information 

through the questionnaire. The observations reported here are 

derived mainly from these questionnaire responses. 

EXAMINING MITIGATION 

We postulated that the Loma Prieta earthquake should focus agencies' attention on whether or not the mitigation path 

they are pursuing is the most appropriate for their local hazard and development context. Assessment of mitigation effectiveness was addressed in two general ways: one was to 

have local agency staff describe ways in which they think 

their mitigation programs served to avert-or did not avertdisruption or damage as intended; the other was to examine 

their choice of new mitigation initiatives in the earthquake's 

aftermath. 

In order to examine mitigation it was important to identify 

where in the governmental structure mitigation planning and 

program implementation are carried out, in hopes of obtaining a fairly complete picture of both programs and plans within 

the jurisdiction. We assumed that these Bay Area jurisdictions would have recognized their earthquake risk, that is, 

would not have been surprised to experience the Loma Prieta 
LOCAL EARTHQUAKE MITIGATION PROGRAMS-PERCEPTIONS OF THEIR EFFECTIVENESS D37 

earthquake; it was important, however, to get some sense of 

what aspects of the community a particular jurisdiction'believed were vulnerable to damage from such an earthquake. 

INSTITUTIONAL LOCATION OF LOCAL RESPONSIBILITY FOR MITIGATION 

The question of who is charged with planning or implementing mitigation efforts was not intended to be part of this 

study. However, initial interviews clearly indicated that the 

distribution of efforts among specific agencies varies between 

communities, and also that one agency is not necessarily aware 

of what another agency has done or is planning with respect 

to earthquake mitigation. This is in part because city organization differs between communities; in part it is the result of 

situational factors within agencies, such as the presence of a 

staff member with a particular commitment to mitigation, or 

traditional locations for types of activities. 

In the absence of information as to which agency was responsible for mitigation programs, the questionnaires were 

directed to specific agency heads. As anticipated, in many 

instances completion of the questionnaire was delegated to 

some other person or persons considered most knowledgeable about the jurisdiction's earthquake mitigation activities. 

Often only one questionnaire was returned from a jurisdiction, with different agency representatives contributing to its 

completion. It is likely that the most complete responses were 

obtained on those questionnaires where several departments 

collaborated. At the same time, responses provided some evidence that departments do not necessarily confer with each 

other and will not necessarily be aware of activities or similar goals in other departments. 

Among the agencies that contributed to the completion of 

the questionnaires (as noted on the front page of each questionnaire received), there are 13 building officials or building 

departments. Someone in public works, which in many communities is the location of the building inspection department, 

is listed on 7 of the returned questionnaires; 11 respondents 

identified themselves as representatives of planning or community development departments; and 5 as representatives 

of emergency services, such as the local office of emergency 

services or fire or police departments. In a few instances, 

someone representing a redevelopment agency or special program for unreinforced masonry (URM) structures participated 

in the response, or someone from administration. 

These observations imply that efforts to disseminate technical information to appropriate agencies or divisions must 

carefully consider general assumptions about where certain 

functions are carried out in local government. These observations further imply that comprehensive community strategies for earthquake hazard mitigation are not likely to be developed unless this separation of objectives and tasks within 

a jurisdiction is overcome. 

LOCAL UNDERSTANDING OF VULNERABILITY 

The belief that some specific area or type of construction is 

particularly vulnerable to damage can be a major factor in 

deciding which mitigation measures to adopt. Contrary to 

initial media portrayals of strong earthquakes, major portions 

of the development within even the higher intensity zones 

associated with recent earthquakes in the western United 

States have suffered mainly minor damage. Major damage 

has been concentrated in specific locations, in specific building types, or in combinations of location and building type. 

Some of the absence of damage can be attributed to the mechanics of the particular earthquake. The rest is attributable 

to the application of geotechnical, seismic, and engineering 

information and technology. Misconceptions on the part of 

decisionmakers about what is and is not vulnerable to the 

more probable types of earthquakes in their region (or what 

part of the nondamage is due to the fortuitous character of a 

particular earthquake) can lead to complacency about the need 

to address the hazard. 

We examined local agency understanding of the damageand nondamage-related to the Loma Prieta earthquake in 

two ways. First, the questionnaire asked for a description, in 

very general terms, of the damage level experienced in their 

community or county. We asked for the typical level of darnage (on a scale of none to extensive) across several categories of structures, including unreinforced masonry (URM) 

buildings, nonductile concrete buildings, simple buildings 

(typically for warehouse use) constructed of prefabricated 

slabs tilted into place at the site, bridges and roads, and other 

residential or commercial buildings. The responses indicated 

variations between categories and between communities and 

also provided examples of other factors respondents thought 

contributed to some of the damage in their jurisdictions. For 

example, one respondent noted that some of the damage was 

in an area built up under the 1960-70 building code; another 

indicated that many houses on stilts or in areas of fill were 

damaged. Chimney damage was mentioned by several. 

The questionnaire next asked if any of the damage was unexpected for an earthquake of this magnitude. The most common response to this question was no, they were not surprised 

by the damage in their area. Several, most typically from communities that had only minor damage or no damage, offered 

that they were surprised they didn't have more damage. This 

suggests (1) an awareness on the part of many of the jurisdictions before the earthquake of the lack of seismic resistance 

for some aspects of their built environment and (2) an awareness that part of the built environment might still be considered vulnerable, even if not affected by this particular earthquake. 

A few respondents mentioned examples of unexpected damage in their communities, including: equipment dislodged by 

the strong vertical acceleration associated with this particular earthquake, even where devices to resist the more typical 

lateral movement had been installed; greater ground movement in bay muds than expected, leading to damage to some 
D38 RECOVERY, MITIGATION, AND RECONSTRUCTION 

types of structures in those areas; disruptions to an auxiliary 

water supply system; unexpectedly great variation in damage related to soil-type microzones; the exacerbation of longterm sliding on sloping ground; unexpectedly great chimney 

damage in a particular community; and damage, albeit minor, to a specific newly constructed neighborhood. Both expected and unexpected damage could be viewed as sources 

of insight into what shoulld be priorities for future mitigation 

measures. 

We also asked these agency representatives if they were 

surprised by damage elsewhere in the region, whether or not 

there had been damage in their area. Again, most responded 

that, for the most part, they had not been surprised. Observations about unexpected damage elsewhere included the Bay 

Bridge damage, the Hyatt Hotel near the San Francisco airport, and the severity of damage at large distances from the 

earthquake source. Again, there were a few mentions of the 

lack of damage in some specified places where it would have 

been expected. 

EXPLANATIONS OF DAMAGE AVERTED 

There are a variety of sources of information on the specific damage that the Lorna Prieta earthquake caused in these 

Bay Area communities (see, for example, Association of Bay 

Area Governments, 199 I ; California Seismic Safety Commission, 199 1, p. 33-48; Earthquake Engineering Research 

Institute, 1990). In particular, eligibility for the Federal and 

State assistance programs requires extensive documentation 

of the damage and of repair costs. Descriptions of damage 

also are provided by teams of engineers and other specialists 

interested in documenting certain phenomena. In our questionnaire we approached damage from another angle by focusing on the damage that did not occur, and the reasons for 

this, by asking about damage averted. The question read, "... 

do you think that some types of damage from the earthquake 

were less in your community/county than they might have 

been because of specific measures taken to reduce damage...?" 

This question was designed to elicit examples of measures 

that were perceived to have made a difference, even if small, 

in reducing the consequences of the earthquake in that community or county. Respondents from communities that had 

experienced little or no damage generally did not answer the 

question. This is unfortunate, but may be due to a correct 

perception on their part that the lack of damage was more 

related to the characteristics of the earthquake than to actions 

taken by the community. 

Table 1 lists all responses to this question and the respondents' description of the program or requirement to which 

they attributed the damage reduction. Some communities gave 

several examples. The types of damage averted fall into three 

familiar categories: the reduction or elimination of structural 

damage to recent (since about 1960) construction; the reduction of damage to nonstructural aspects of buildings, such as 

fittings and contents; and the reduction of damage to existing 

older, hazardous buildings. 

Good engineering design and appropriate codes are given 

the credit for having protected the newer buildings in many 

communities. Most of the answers referred specifically to the 

application of the Uniform Building Code, thus implying the 

importance of requirements that have to be met for various 

types of structures. A few of the responses explicitly recognized enforcement of the Code as the key. For the reduction 

of losses in nonstructural elements, the responses contained 

more of a mix of required practices and measures left to the 

discretion of the building owner. When measures depend on 

voluntary application, it has to be assumed that a much smaller 

proportion of the hazards will have been affected than for 

required measures. Nonetheless, as awareness grows that certain types of measures work, it becomes more likely that 

greater numbers of building owners will implement those 

measures voluntarily. Evidence of effectiveness, and in particular cost-effectiveness, may increase the likelihood that 

such measures will eventually be required, at least for new 

construction and maybe for certain existing buildings. However, most communities lack any effort to track and evaluate 

the success of these voluntary efforts, or to engage in costeffectiveness analyses. 

The examples given of damage averted in potentially hazardous existing buildings were heartening but have affected 

a fairly limited number of buildings. Two examples are important in that they indicate a community's willingness to address one or more of its own government buildings that had 

been assessed as lacking in seismic resistance. The enforcement of seismic requirements when buildings are altered was 

mentioned by one community. While this sounds like a fairly 

simple approach, it has raised complex issues about what standards to use, the effects on owners' willingness to upgrade 

older buildings, and cost-effectiveness. Two communities 

believed information provided to building owners had 

prompted at least some amount of voluntary strengthening of 

buildings susceptible to earthquake damage. 

Experience in the initial personal interviews indicated that 

the question on "damage averted was puzzling to many at 

first. It is much more difficult, and a more subjective task, to 

think in terms of damage averted rather than damage observed. 

Of the respondents who addressed this question, some only 

indicated one or two examples, while others provided several. The variation in the ability to provide examples from 

one jurisdiction to the next is not readily explainable. The 

difference could be the result of any of the following: little 

attention to mitigation in some communities; uncertainty about 

whether measures had been effective; or a tendency to lose 

awareness of the implications of mitigation activities once 

they are routinized. For example, the fact that more respondents did not mention their local building code, at a minimum, in response to this question could indicate a failure to 

understand the question but may mean that the implications 

of the codes for seismic safety are taken for granted. 

To the extent that the latter explanation holds true, for 

purposes of promoting additional loss reduction efforts it may 

be important to raise awareness of the significance of the use 
LOCAL EARTHQUAKE MITIGATION PROGRAMS-PERCEPTIONS OF THEIR EFFECTIVENESS D39 

Table 1 .-Examples of damage believed averted by local mitigation activities undertaken before the Loma Prieta earthquake 

[From questionnaire responses to the question, "Do you think that some types of damage from the earthquake were less 

in your community/county than they might have been because of specific measures taken to reduce damage or prepare 

for an earthquake? Please list the type of damage that was averted and describe the activity that was responsible for 

the reduction."] 

Type of damage believed averted Local measure(s) credited with averting damage 

Structural damage reduction in recent construction 

Failure of any modem buildings 

Major or extensive damage to new structures 

Residential and commercial building damage 

Separation of structure from foundation1 

footing 

Racking due to reduced wall area or wall 

damage 

Cripple wall failure or damage 

Damage to buildings in general 

Damage to buildings in areas of bay mud 

Damage to all structures 

Building code that requires all buildings to be 

designed for seismidlateral forces 

New structures were engineered at higher standards 

Enforcement of most current building, mechanical, 

plumbing and electrical codes 

Application of provisions of the Uniform Building 

Code, Chapter 23 

Application of Uniform Building Code, Chapter 23 

since 1955, with 1973 update 

Application of Uniform Building Code, Chapter 23 

since 1955, with 1973 update 

Buildings were constructed to model code 

requirements 

Local code for identified bay mud area more 

restrictive than Uniform Building Code since 1972 

Local emphasis on quality design and details, and 

plan review and inspection by the city 
D40 RECOVERY, MITIGATION, AND RECONSTRUCTION 

TABLE 1 .-Examples of damage believed averted by local mitigation activities undertaken before the Loma Prieta 

earthquake-Continued 

Damage reduction related to nonstructural aspects 

Contents damage at [specific] construction 

company 

Contents tie-down requirement 

Ammonia vessel rupture 

Tipping or breakage of hot water heaters 

Personal injury in workplaces 

Vessel was secured to a concrete pad and was 

properly strapped 

Voluntary efforts of individuals to strap hot water 

heaters 

Voluntary programs of some businesses to develop 

earthquake safety and evacuation plans 

Nonstructural failure in the emergency 

operations center 

Facility survey had been done and mitigation 

measures applied in 1988-89 

Broken windows and flying glass 

Chimney separation or damage 

Damage to equipment and buildings 

Voluntary increase in use of plastic film to cover 

window glass as encouraged through ongoing 

public education by county and city emergency 

services organizations since 1970's 

Application of Uniform Building Code, Chapter 37 

since 1984 

Local code and strong enforcement of Uniform 

Mechanical CodeIUniform Building Code 

requirements for water heaters and other equipment 

tie-downs since 1972 

Damage to underground piping systems in 

specified bay mud area 

Damage to utility connections at buildings 

Collapse of ceiling systems 

Local code requirement for nonmetallic piping in 

specified area to reduce corrosion since 1972 with 

198 1 modifications 

Local construction community emphasis on good 

practice of using flexible utility connections to 

buildings in bay mud areas since 1970's 

Uniform Building Code lateral-force criteria for 

supports of ceilings as per latest model codes from 

State Building Standards Commission 
LOCAL EARTHQUAKE MITIGATION PROGRAMS-PERCEPTIONS OF THEIR EFFECTIVENESS D41 

TABLE 1.-Examples of damage believed averted by local mitigation activities undertaken before the Loma Prieta 

earthquake-Continued 

Damage reduction in existing hazardous buildings 

Parapet and ornamentation failure 

Failure of Candlestick Park Stadium 

structure 

Failure of building upgrades 

Damage to older wood frame homes 

Damage to some unreinforced masonry 

structures 

Damage to masonry fire station, library 

Long-term continuing program to reinforce parapets 

and related hazards 

Seismic upgrade project completed 

Long-term enforcement of special seismic upgrade 

requirements 

Increased number of homes voluntarily applying 

foundation bolts as retrofit, encouraged through 

ongoing public education by county and city 

emergency services organizations since 1970' s 

Voluntary retrofit stimulated by information 

available and emphasis of 1986 California 

Unreinforced Masonry Building Law (Senate 

Bill 547) 

City decision to reinforce during conversion and 

construction 

of updated building codes as part of the mitigation process. 

There may be considerable political value in being able to 

remind the public that the survival of buildings and services 

in the community was not necessarily accidental, but a result 

of intelligent decisions on the part of building and planning 

officials and private citizens, followed by the reminder that 

more of these types of decisions remain to be made. This is 

particularly true for extending lessons learned to other 

seismically vulnerable areas of the United States that have not 

recently experienced a strong earthquake but are lacking in 

something as basic and significant as building codes relating 

to seismic resistance. 

The perception of current building codes as an effective 

mitigation strategy was revealed in the questionnaires and 

interviews in other ways besides responses to this question. 

For example, several jurisdictions characterized their 

development as too new to be concerned about the seismic 

hazard because their growth had occurred in the years since 

more stringent building standards were adopted. This 

assumption may or may not be totally correct, because the 

short duration of the ground shaking associated with the Loma 

Prieta earthquake (about 8 seconds for the greatest intensity) 

did not provide a particularly severe test for many buildings. 

Nonetheless, the widespread enforcement of recently revised 

building codes with seismic provisions has to be viewed as a 

major cause of earthquake loss reduction in the San Francisco 

Bay Area. 

The list in table 1 presents an array of examples of both 

required and voluntary efforts that the respondents said they 

believed had been effective in reducing the overall impact of 

the earthquake. During the initial personal interviews, two 

different building officials pointed out a reverse approach for 

making judgments about damage that was averted. They observed that a quick analysis of their post-earthquake damage 
D42 RECOVERY, MITIGATION, AND RECONSTRUCTION 

inspections provided insights about certain fairly simple measures, such as chimney reinforcement or foundation bolting 

and bracing, that would have prevented damage. For example, 

the examination of inspection results in one community revealed that well over half of the inspections performed after 

the quake were for chimney damage; in another, inspections 

of older homes that had been displaced from their foundations 

had placed major demands on the damage inspection process. 

These officials noted that, had requirements been in place 

to address these weaknesses, not only would the post-earthquake demand for inspections have been far less, but hundreds of homeowners would have been spared the costs and 

the disruptions to their lives which this damage caused. Another interview respondent suspected that cost-effectiveness 

studies of some of the less complicated measures, in particular those related to dwelling damage, would prove favorable, 

and therefore could be very valuable for promoting programs. 

If it were possible to factor in the nonmonetary aspects of the 

disruption and stress, the ratio of prequake strengthening costs 

to post-quake repair costs would be even more favorable. 

THE LOMA PRIETA EARTHQUAKE AS A 

CATALYST FOR SUBSEQUENT MITIGATION EFFORTS 

Various analyses have suggested that the occurrence of an 

earthquake (local or otherwise) helps to promote local reevaluation of acceptable risk and briefly widens the constituency 

for earthquake mitigation so that local priorities can be rearranged to provide for the implementation of new preparedness or mitigation measures. Observations about the factors 

contributing to damage in the Loma Prieta earthquake might 

well prompt jurisdictions to change what they had previously 

considered a reasonable and feasible level of effort directed 

at earthquake mitigation. The experience also may have provided direct evidence of what effectively reduces damage, or 

perhaps changed the local definition of acceptable risk with 

respect to some type of vulnerability. 

Besides being asked what earthquake mitigation programs 

and plans they had before the Loma Prieta earthquake, respondents were asked about plans and programs initiated since 

the earthquake. So that respondents would think about a wide 

variety of measures, the questionnaire asked them to describe 

their post-earthquake activities in the following seven categories: 

Planned or actual revisions in land-use ordinances 

Revisions in procedures for implementing existing rules 

or regulations 

Proposed or adopted changes in standard construction 

practices 

Proposed or adopted changes in the seismic safety element of the general plan 

New programs or regulations aimed at reducing the potential seismic hazard from existing buildings (including programs in response to the 1986 Unreinforced 

Masonry Building Law) 

Development or provision of outreach or training programs for employees, businesses, residents, or other 

special population groups on earthquake safety measures 

Involvement in community redevelopment efforts that 

specify seismic safety as an element of the program 

EXISTING BUILDINGS 

Attention to existing buildings is the most frequently mentioned post-earthquake mitigation activity. Virtually all activity described in relation to existing buildings focused specifically on unreinforced masonry (URM) buildings. 

Generally, the programs were developed in response to the 

California URM law (the 1986 Unreinforced Masonry Building law, often referred to as Senate Bill 547). This law requires cities and counties to inventory all unreinforced masonry buildings and establish a local program to mitigate the 

hazards in these buildings. These programs must include, at a 

minimum, notifying building owners about the potential hazards of their building and developing a plan to address the 

building hazard. To comply with the URM law, communities 

were to have completed their inventory of URM buildings by 

January 1990. Many communities were well along in the process or had already completed this task by the time of the 

Loma Prieta earthquake in October 1989. Thus momentum 

already existed for developing mitigation programs related 

to the URM buildings (California Seismic Safety Commission, 1990). Certainly the URM Law (SB 547) has been the 

central driver for the progress made in addressing the URM 

building hazard at the local level, and some respondents stated 

explicitly that the law was probably more important than the 

Loma Prieta earthquake in prompting their actions related to 

URM buildings. However, other respondents noted that because of the Loma Prieta earthquake, they had decided to 

switch from a voluntary to a mandatory program, or that they 

had speeded up the process from what was originally planned. 

For communities like Watsonville and Santa Cruz, the earthquake eliminated much of the URM building hazard, providing a graphic illustration of what URM strengthening is intended to prevent. Both these communities also had examples 

of URM buildings that had been reinforced and that fared 

considerably better than the unreinforced buildings. 

The initial personal interviews also revealed a need to establish programs for strengthening other types of existing 

buildings, such as the prefabricated tilt-up buildings, in widespread use as production and warehouse facilities; older concrete frame structures, especially those housing schools and 

critical facilities; mobile homes not tied to footings; and wood 

frame houses built before codes required adequate tie-ins with 

the foundation. The Loma Prieta earthquake provided examples of hazards associated with these building types, as 

well as with URM buildings. Older concrete frame buildings 
LOCAL EARTHQUAKE MITIGATION PROGRAMS-PERCEPTIONS OF THEIR EFFECTIVENESS D43 

in California, older wood frame houses, and tilt-up buildings 

constructed before code changes will have to be treated 

through measures focused on existing buildings; future tiltup and similar-style buildings can be addressed with new 

construction standards. 

The interviews and questionnaires clearly indicate that far 

less attention has been paid to these other types of hazardous 

buildings than to URM buildings. This illustrates the important effect of the state-level policy for attending to the URM 

hazard. Even though many local governments resent state 

initiatives that affect local discretion on issues, others will 

acknowledge that it can be very helpful to have important 

requirements emanate from the state, thereby making local 

action an implementation issue rather than a political issue. 

The California policy, at a minimum, provides building owners with necessary information and goals to address hazards 

in their buildings. This permits the local jurisdiction discretion about the schedule for mitigation and whether to make 

strengthening mandatory, thereby leaving the definition of 

acceptable risk to local policy makers. 

Both Federal and California State policies reflect the belief that URM strengthening, at least theoretically, is an effective approach to reducing one type of loss and should be 

promoted. Implementation of URM strengthening programs 

has not been considered very feasible at the local level because owners often cannot afford to do what is necessary and 

the jurisdiction cannot afford to provide adequate financial 

incentives to make it cost effective for owners. Nonetheless, 

some jurisdictions have decided that the risk represented by 

these buildings is not acceptable. They have therefore established objectives for the amount of damage that is acceptable 

(that is, life safety only, or preservation of functionality) and 

required that these buildings meet standards that keep damage at or below that level in future typical earthquakes. Because strengthening programs can be such major social and 

economic issues for communities, these programs will be most 

feasible, as one interview respondent noted, in those communities with the fewest URM buildings. In other parts of the 

United States, vulnerable existing buildings constitute a larger 

portion of the building stock than in California. In those areas URM strengthening may not be economically feasible at 

the local level unless some sort of financial assistance or subsidy is provided. However, when the costs of losing these 

buildings from the building stock, providing disaster recovery assistance, and grappling with the provision of replacement housing is compared to the cost of subsidizing their 

strengthening, such programs may nonetheless prove desirable. 

Evidence that URM programs are being adopted following 

the Loma Prieta earthquake does not necessarily mean that 

communities have, on their own, decided the measure is too 

effective to ignore. State policy is a major factor in the development of URM strengthening programs. Progress to date is 

therefore not necessarily related to the Loma Prieta earthquake, although that event probably has helped make implementation of the program less difficult to justify within some 

communities. 

SEISMIC SAFETY ELEMENTS AND LAND-USE 

ORDINANCES 

One of the more sobering lessons learned from the Loma 

Prieta earthquake was an appreciation of the amount of damage to the built environment caused by local soil and ground 

conditions and by unrecognized geophysical hazards (Earthquake Engineering Research Institute, 1990, chap. 4; Federal 

Emergency Management Agency, 1990). The earthquake also 

reactivated landslide areas and led to a renewed awareness of 

the extent of the liquefaction hazard, particularly on the margins of San Francisco Bay. Respondents in the Santa Cruz 

area during the initial in-depth interviews pointed out that 

damage patterns proved the effectiveness of the combined 

use of building codes and geologic-hazard review requirements. Much of the damage there was to older structures built 

before such measures were in place, to structures built without a permit, or in areas where the hazard from soil conditions had not heretofore been recognized. 

Since 197 1, the California State Planning law has required 

cities and counties to include in their general plan the identification and appraisal of seismic hazards. In 1984, this seismic safety element of general plans was combined with other 

elements into a single safety element under which jurisdictions must address ways to protect the community from unreasonable risks, including seismic risks. This and other laws 

that require attention to seismic risks have helped to ensure 

that seismic matters are included in local planning programs 

and have served to heighten the awareness of city officials 

and the public regarding seismic hazards and options for dealing with them (California Seismic Safety Commission, 1985). 

These laws have not necessarily resulted, however, in specific actions being taken to mitigate the hazards described. 

Some respondents to the questionnaire indicated that they 

were preparing to review or had reviewed the information in 

their seismic safety element, and revised it if necessary, since 

the 1989 earthquake. However, few examples were provided 

of changes in land-use or other ordinances that would indicate these jurisdictions believed they needed to take a different approach to better identify or mitigate their existing seismic hazards. If such reviews were done in light of what was 

experienced in the Loma Prieta earthquake only, they may 

not adequately address the consequences of movement on 

other faults in the area or of larger earthquakes. Communities that claimed to be working on revisions to land-use ordinances included two of the communities that sustained the 

greatest damage in the Loma Prieta earthquake. 

In 1990, the State adopted the Seismic Hazard Mapping 

Act (1990 Statutes, Chapter 1168 [AB 38971). The Act calls 
D44 RECOVERY, MITIGATION, AND RECONSTRUCTION 

for the California Division of Mines and Geology to prepare 

maps that will be used to identify seismic hazard zones. The 

establishment of these zones will facilitate the use of seismic 

hazard information in land-use regulation and for establishing construction requirements or other regulations for specific types of areas, should communities choose such approaches to deal with their particular hazards. As before, the 

feasibility of implementing such ordinances will be a major 

consideration in deciding whether or not to enact them. For 

most of the State, the designation of seismic hazard zones 

will not occur immediately after the Act was passed, as the 

program did take several years to complete. Once it is completed, the existence of well-defined zones may also affect 

other policies, such as those applied to financing or insurance for development in hazard zones. 

OUTREACH, EDUCATION, AND 

OTHER ACTIVITIES 

Training and outreach typically are not particularly controversial programs to implement, and their costs are fairly low 

compared to other measures. To the extent that the techniques 

promoted are theoretically effective, they can make a major 

contribution to the reduction of losses if correctly applied by 

a significant proportion of building owners. Many respondents to the questionnaire expressed a belief that citizens or 

businesses do voluntarily apply measures they learn through 

these educational outreach efforts, though none cited any evidence of the actual extent of such applications. Many stated 

that they had provided post-earthquake education of some 

kind to either city employees or the public, but most indicated that this was basically a continuation of what they had 

been doing before. The in-depth interviews revealed that jurisdictions commonly create their own informational materials for education of the general public, even on generic procedures, despite the existence of many already prepared 

materials available through Federal, State, and regional programs. 

Virtually no other examples were provided of post-earthquake measures these jurisdictions consider effective and thus 

worth implementing. An oversight in the questionnaire was 

the omission of the development of repair or reconstruction 

standards from the list of potential post-earthquake activities. Damaged buildings presented a major challenge to the 

jurisdictions. The standards applied to repair are important to 

the reduction of losses in future earthquakes, but in many 

jurisdictions this issue had not been addressed before the earthquake. In those areas, repair standards needed to be developed quickly after the earthquake to be of most use. This called 

for tough policy decisions and demanding compromises to 

craft standards lenient enough to permit recovery but tough 

enough to achieve acceptable seismic safety levels. This dilemma was identified in the personal interviews as being particularly difficult for historical buildings, and also in areas 

where the earthquake revealed geologic hazards not previously recognized there and thus not addressed in geologic 

hazard reviews of those sites. 

SIGNIFICANT CHANGES RELATED TO THE 

LOMA PRIETA EARTHQUAKE 

Although examples of measures initiated following the 

Loma Prieta earthquake are provided above, the overriding 

impression from reviewing the responses to the questionnaire 

is that the earthquake prompted very few communities to initiate additional mitigation measures in the years immediately 

following the quake. Besides having respondents list the prequake and post-quake mitigation activities in their community, the questionnaire also asked for a subjective assessment 

of the effects of the earthquake on local concerns or activities. This question read, "In your view, do you think that the 

approach your community is taking to prepare for and reduce 

the potential for damage from an earthquake has changed in 

some significant way because of the Loma Prieta earthquake?" 

In answer to this question, several respondents mentioned 

that there was now a greater awareness of what an earthquake 

could do, or of the potential vulnerability of their community 

to future earthquakes. This is a somewhat disappointing answer, because it does not address whether this awareness was 

leading to more aggressive efforts to reduce future losses. 

More than a third of the respondents indicated increased attention to emergency response preparedness, but did not mention loss reduction measures. Other types of answers included 

(1) a greater sense of urgency, (2) greater awareness and action on the part of top administrators, (3) more aggressive 

approach to URM buildings, and (4) increased attention to 

geotechnical review in areas now recognized as particularly 

hazardous. Some mentioned their impression that more individual citizens were voluntarily taking measures such as strapping their hot water heaters, anchoring their houses better, 

and reinforcing chimneys, or at least they were asking for 

information on how to do these things. One person stated 

frankly that the earthquake raised awareness, "but not enough 

to fund some key programs." 

Both the initial interviews and the more concise responses 

to the questionnaire imparted the same impression: despite 

the evidence from the Loma Prieta earthquake that mitigation efforts both can help and are lacking in many places, the 

actual adoption and implementation of loss reduction measures is still an uphill battle. In the interviews a few of the 

respondents acknowledged that they assumed there was a 

"window of opportunity" for taking advantage of heightened 

awareness and concern about earthquake damage, but they 

knew that it would not be open long, and perhaps not open 

very wide. By the end of the first year, this window was perceived as closing rapidly in conjunction with the worsening 

fiscal condition of the State and of most local jurisdictions. 

Even during times of fiscal stability, virtually all communities face tradeoffs between directing resources to immediate threats to the community's well being, such as crime, de- 
LOCAL EARTHQUAKE MITIGATION PROGRAMS-PERCEPTIONS OF THEIR EFFECTIVENESS D45 

teriorating education, or traffic congestion, and directing them 

to more indeterminate threats such as earthquakes and other 

highly disruptive events. Earthquake mitigation programs, in 

particular, typically cannot compete on the local political 

agenda with more pressing everyday problems. Even an event 

such as the Loma Prieta earthquake may not provide an impetus beyond those communities most directly affected. Under these circumstances, earthquakes themselves remain the 

most effective, even if the least desirable, means of removing 

development vulnerable to earthquake damage. 

USEFULNESS OF TECHNICAL ASSISTANCE SOURCES 

valuable to these local agencies; small numbers suggest that 

a source has not been particularly visible or valuable. However, a small number of mentions should not automatically 

be assumed to mean that the source of assistance has little to 

offer. It is more appropriate to say that these findings indicate 

which sources were or were not particularly applicable to the 

needs of these local building and planning officials. Some 

may be well suited and useful to other audiences, such as 

consulting engineers, practicing architects, or teaching professionals, and thus the path of their effects at the level of 

local agencies is more circuitous. The value of any specific 

source of technical assistance must be assessed against its 

own intended objectives. 

MOST FAMILIAR SOURCES 

A central element in both the National Earthquake Hazard 

Reduction Program (NEHRP) and in California State efforts 

to promote earthquake preparedness and hazard mitigation is 

the provision of information to inform and guide local programs. Several types of hazard information and mitigation 

program guidance have been provided for the earthquake hazard in general, and others for use in California and the Bay 

Area specifically. For example, types of technical assistance 

available to California officials include the following: 

Information emanating from the Federal level, fairly generic in nature and typically designed to be widely applicable. 

Sources provided by the State of California, typically 

focused on California seismic issues and policies. 

Regional technical assistance and information from education agencies focused on regional issues and accessible to the jurisdictions in the region. 

Sources particularly relevant to a specific profession, 

focused on solutions to the problems typically addressed 

by members of that profession. 

The availability of persons with special knowledge, including in-house expertise or private consultants, that 

can extend agency expertise regarding a specific problem. 

The questionnaire listed 14 sources of information and technical assistance and instructed respondents to indicate those 

they were familiar with, had used, and had found most helpful. Certainly not all sources of technical assistance are captured in the questionnaire list, but the selection represented a 

variety of major sources of information available in recent 

years to California agencies involved in planning or implementing earthquake hazard mitigation programs. These 

sources all have the objective, to a greater or lesser degree, of 

enabling practitioners to use the information to reduce risk. 

Responses to this question were received from 30 different 

respondents in 24 jurisdictions. 

The information sources the respondents were asked about 

are shown in table 2, along with agency responses. High numbers in the table suggest that a source has been visible and 

Agency representatives responding to the questionnaire 

were familiar, on average, with about half of the 14 assistance sources listed. Five of the sources were recognized by 

more than half the respondents. The single source that the 

most respondents (24 out of 30) indicated as familiar was the 

Bay Area Regional Earthquake Preparedness Project 

(BAREPP)-more recently renamed as the Earthquake Program of the California Office of Emergency Services Coastal 

Region. It should be recognized that the breadth of BAREPP7s 

activities probably gives it the greatest number of paths to 

people's desks. BAREPP not only provides direct, personal 

technical assistance for planning, and presentations to provide preparedness or mitigation information, but also produces and distributes a large number of documents related to 

mitigation planning and programs that vary in focus and level 

of technical detail. BAREPP has been associated with many 

widely publicized education and preparedness activities such 

as the annual Earthquake Week and a large conference held 

one year after the Loma Prieta earthquake. BAREPP also 

serves as a means for delivering guidance developed by others, including sources on the list such as the Applied Technology Council, the Federal Emergency Management Agency, 

the United States Geological Survey, and other experts. 

A similar number of respondents (24) indicated that they 

were familiar with information provided by their professional 

associations. This type of dissemination represents many different sources, but refers most typically to professionals providing information to others in the same profession (for example, engineers) or the same agency function (for example, 

building officials) through association journals, local chapter 

meetings, and conferences. Organizations such as these can 

be very instrumental in informing members of the implications of research findings and issues for their profession. These 

associations also can advocate for attention to earthquake 

hazard mitigation as good practice. Since they must attend to 

a wide array of concerns of the particular profession, however, the amount of attention given to earthquake mitigation 

will necessarily be limited. 
D46 RECOVERY, MITIGATION, AND RECONSTRUCTION 

Table 2.-Number of agency respondents indicating familiarity with and helpfulness of sources of information and 

technical assistance 

[From questionnaire responses in regard to list of 14 sources given below. Respondents were asked to indicate all sources 

with which they were familiar, the 3 they found most useful before the Loma Prieta earthquake, and the 3 they found 

most useful after the earthquake. Not all respondents completed all questions. N, number of responses to a question. 

Some respondents indicated fewer or more than 3 sources as most useful.] 

Source and type of information or technical Familiar Most helpful, Most helpful, 

assistance sources pre-quake post-quake 

(N = 30) (N = 21) (N = 17) 

Federal Emergency Management Agency, 14 3 3 

Earthquake Hazard Reduction Series (also 

known as "the yellow books" because of 

their covers) 

U.S . Geological Survey hazard assessments 

and information dissemination from these 

assessments 

Building Seismic Safety Council workshops 

or publications 

Applied Technology Council workshops 

or publications 

California Seismic Safety Commission 

documents, program priority statements, 

contacts with staff 

Bay Area Regional Earthquake Preparedness Project multijurisdictional earthquake 

planning assistance; staff contacts, consultation, meetings; handbooks and planning 

guides; public education materials; workshops and conferences 

Association of Bay Area Governments 21 4 1 

earthquake hazard data or maps; planning 

information; workshops and conferences 
or earthquakes 

Specialized training sessions (such as 

California Specialized Training Institute 

or Federal Emergency Management 

Agency' s Emmitsberg Training Center) 

In-house expertise (tap what is available) 

Outside consultants, hired for special 

projects 

Postearthquake briefing sessions (following 

major earthquakes in Mexico City; Whittier, 

California; Armenia) 

Two other sources of information and assistance also were 

cited as familiar by at least two-thirds of those who answered 

this question. These are the Association of Bay Area Governments (ABAG) and the California Seismic Safety Commission (CSSC). The initial interviews and comments on the 

questionnaires indicate that when respondents mentioned 

CSSC, they were often thinking about assistance with complying with the California URM Law (SB 547). There were 

no specific comments about ABAG activities, but ABAG7s 

more notable efforts in recent years related to earthquakes 

include providing information on earthquake risks and hazardous areas in the San Francisco Bay Area and sponsoring 

conferences on important issues such as liability in the area 

of earthquake preparedness and mitigation. 

Many of the other sources on the list were noted as familiar by about half the respondents. The two sources with the 

lowest recognition were the Building Seismic Safety Council (BSSC) and the American Institute of Architects (AIA). 

The lack of familiarity with the work of the BSSC on the part 

of planners and building officials at the working level is probably not surprising. Its contributions to the development of 

consensus on building standards and approaches to seismically 

resistant design are directed at a much more limited audience, and the fruits of its work are probably most likely to 

reach practitioners through their professional associations, or 

as effects on codes. The AIA was included as a source separately from other professional associations because of special projects directed at providing education on approaches 

to seismic safety among the design professions. Because its 

efforts were national in focus, there would have been less 

opportunity for any particular agency professional to have 

had exposure to its workshops. 
D48 RECOVERY, MITIGATION, AND RECONSTRUCTION 

MOST HELPFUL SOURCES 

The respondents were asked which sources they had actually used for their mitigation activities before the Loma Prieta 

earthquake and which three had been the most useful to them. 

Compared to the question on familiarity, where respondents 

listed on average seven sources, the average number respondents said they used before the Loma Prieta earthquake was 

between three and four. About 70 percent (21) of the respondents addressed the question of which three sources were the 

most useful to them for mitigation planning and program development before the earthquake. Some respondents listed 

fewer than three, and a few, perhaps because of the combined 

efforts of multiple individuals in completing some of the questionnaires, indicated more than three as particularly useful. 

BAREPP, which had been the source most familiar to the 

agency representatives, also was identified as among the three 

sources most useful before the earthquake by about 60 percent of the respondents. About half of the respondents included the category "professional associations" among the 

most useful sources of technical assistance. Third in number 

of mentions as most useful came the specialized training sessions, such as those provided by the California Specialized 

Training Institute (CSTI), and information from the California Seismic Safety Commission (CSSC). 

Respondents also were asked which sources were most useful to them after the Loma Prieta earthquake. Only 17 of the 

30 respondents were willing to persist in this exercise of describing their use of these information sources through the 

set of five questions. Professional associations and BAREPP 

were mentioned by about half of these respondents (9 and 8, 

respectively) as most useful to them following the earthquake. 

The next three highest, each with 5 mentions, were the Applied Technology Council, the California Seismic Safety 

Commission, and outside consultants. 

Besides obtaining some idea of whether or not agencies 

charged with earthquake hazard mitigation knew and used 

these resources, we also had hoped to see if their use varied 

by type of planning and program activity (such as land-use 

planning, building standards, and education). However, as 

noted above, many jurisdictions prepared a combined response, with appropriate separate agencies filling in those 

items most relevant to them. Therefore, it was not always 

possible to distinguish the responses of one agency from those 

of another in the same community. 

To get a better idea of the potential effects of these information sources, additional details would be desirable to have, 

such as the extent to which the assistance reaches the audience for which it is intended; assessments of the effectiveness and accessibility of the various media (for example, oneon-one exchange, workshops, and documents) for providing 

information; who uses the information; and exactly what the 

information is used for. Detailed data on the effectiveness of 

an organization's information programs are best obtained 

through systematic evaluations of the individual programs, 

conducted in light of their particular objectives. 

IMPLICATIONS FOR THE ENHANCEMENT OF 

TECHNICAL ASSISTANCE 

The two sources of information and technical assistance 

that were reported to be most useful to the staff of local agencies-both before and after the Loma Prieta earthquakewere BAREPP and professional associations. This immediately suggests a general recommendation to provide support 

for these organizations, or ones like them, to carry out their 

functions related to earthquake hazard mitigation. At the same 

time, it is obvious that these two types of sources perform 

these functions quite differently and raise different questions 

about where the greatest leverage can be achieved in providing technical assistance. In addition, both of these sources 

are multifaceted; further detail about which aspects of their 

programs are the most valued by these agency practitioners 

would be important to have when formulating strategies for 

enhancing the provision of technical assistance. 

BAREPP is funded jointly by Federal NEHRP money and 

State funds and has the central objective of fostering earthquake preparedness and mitigation in the San Francisco Bay 

region. Its efforts are almost totally dedicated to enhancing 

local understanding of the regional earthquake hazard and of 

educating a wide range of different audiences in both the public and private sectors about appropriate preparedness and 

mitigation measures. Its services vary from mailing informational brochures to private citizens to making available its 

planning and hazards experts to meet with staff of local agencies. It distributes a large array of technical assistance brochures and handbooks, most of which have been developed 

with public funds, either by itself or by others. Although our 

questionnaire information does not provide details on what 

aspects of BAREPP's services are most valued by the agency 

people, some potentially important characteristics can be suggested: as a source of assistance, BAREPP is centralized, accessible, knowledgeable about local hazards and issues, and 

has off-the-shelf products applicable to many aspects of preparedness and mitigation. 

Professional associations, on the other hand, focus on providing information that is useful to their members in their 

professional lives. Some associations exist for professions in 

general, such as engineers or architects. Others are dedicated 

to the concerns of specific types of functionaries, such as city 

managers, fire chiefs, emergency managers, or building officials. Association activities typically are funded by dues and 

fees paid by the members themselves, and their agendas are 

set by the concerns and information needs voiced by members of the profession. It is through these organizations, and 

through interactions with other members of the same profession provided by association-sponsored journals, newsletters, 

and functions, that practicing professionals share new information relevant to their activities. Professional associations 

develop and promote the use of standards of good practice 

for what individual professionals do. Although only a small 

part of what an association does may be directly related to 

earthquakes, certain characteristics of these associations may 
LOCAL EARTHQUAKE MITIGATION PROGRAMS-PERCEPTIONS OF THEIR EFFECTIVENESS 

make them valuable for helping agency professionals deal 

with earthquake risks. For example, they have the ability to 

screen and funnel information specific to the needs of a particular agency professional (who may be one of a kind in his 

agency or community, as for example a city manager or city 

engineer). This can be particularly important because the 

source of the information will be others who share similar 

concerns and problems, making it a truly credible source of 

information and guidance. Professional associations also serve 

to provide legitimacy for the adoption of land-use or building standards and perhaps some degree of political currency 

in the struggle to have mitigation programs implemented. 

The development of more specific recommendations about 

how to enhance technical assistance efforts demands further 

systematic analyses and critical evaluation of existing approaches. It is important to examine in greater detail those 

information sources deemed as particularly valuable to local 

agency people and to try to understand more about the specific functions those sources perform for them. Attention can 

then be paid to enhancing the performance of these functions, 

whoever is performing them, and to developing the necessary linkages among assistance providers and information 

producers. For example, in the San Francisco Bay region, 

BAREPP performs the function of being a distributor of documents describing how to develop plans and how to reduce 

earthquake damage in a variety of settings. Much of what 

they distribute has been developed by others (for example, 

the Applied Technology Council or independent experts), who 

can focus on the function of developing sound advice, while 

BAREPP focuses on the function of identifying appropriate 

audiences and developing campaigns to see they that receive 

this information. At a future time, or in other places in the 

U.S. with an earthquake hazard, other organizational models 

may be identified or created to carry out these functions as, 

or even more, effectively than does the BAREPP model. 

Another way to select sources of technical assistance for 

special attention is to think in terms of what a particular community wants or needs to accomplish. For example, different 

sources might be best for assisting with the political process 

of getting a long-term mitigation strategy adopted in a community, for helping a community determine the need for special codes to address specific and less common hazards, or 

for helping a department design and implement a specific 

mitigation program such as enhancing the seismic resistance 

of existing tilt-up buildings. The responses of the agencies 

reported in this study suggest that an important objective to 

pursue would be that of getting relevant building codes instituted or enforced in areas where this has not yet been done. 

Another is to promote the widespread application of lower 

cost measures for strengthening existing buildings and minimizing nonstructural hazards, in order both to reduce losses 

and disruption to building owners and to permit responsible 

agencies to focus on more serious post-earthquake problems. 

The source of critical assistance may be different in different 

places, depending on the central focus of a community's mitigation strategy. 

SUMMARY AND CONCLUSIONS 

This study examined the effectiveness of loss-reduction activities at the local government level by asking agency representatives to reflect upon potential damage that did not occur 

during the Loma Prieta earthquake and to think about which 

activities may have averted damage that otherwise would have 

been expected. It also asked agency representatives to describe their mitigation plans and efforts both before and after 

the earthquake and to reflect upon the changes and what they 

are now doing to move forward with mitigation efforts. 

Our findings suggest that (1) well-enforced local building 

codes are viewed as effective in reducing or eliminating damage and, in these California communities, are the primary 

means for mitigating damage; (2) programs aimed at promoting simpler, lower cost measures for strengthening existing 

buildings or reducing nonstructural hazards should be more 

aggressively pursued; (3) sources of information and technical assistance that are easily accessible and locally relevant, 

and those provided by credible sources such as other members of the same profession are viewed as most useful; and 

(4) Federal, state, and regional programs that provide assistance to local jurisdictions should be cognizant of the variety 

of organizational structures within governments, so that vital 

information reaches the appropriate offices or individuals. 

The perceived effectiveness of building codes in mitigating the damaging effects of an earthquake was illustrated in 

several ways. Many participants in the study explicitly mentioned building codes, either in a general sense or with reference to specific portions of the Uniform Building Code, in 

response to the question about damage averted. Some officials in cities where little damage occurred remarked that it 

was the young age of their building stock that was to be credited, indirectly showing their belief in the efficacy of modern 

building standards, which are required for new construction 

in California communities. Many respondents made specific 

mention of the small number of unreinforced masonry buildings within their jurisdiction. This caused them to feel less 

vulnerable to a damaging quake. In some other areas of the 

United States where earthquakes are less frequent than in 

California, building codes are less attentive to seismic safety. 

Officials there should be encouraged to adopt more stringent 

standards and to enforce such codes locally. The cost is relatively low when only new construction is targeted. Every year 

that passes without relevant standards being applied to new 

construction increases the number of existing buildings that 

may eventually demand special attention by state legislators, 

city leaders, or insurers and lenders; or that may contribute to 

the loss of life, injury, and relief and recovery costs when an 

earthquake does strike. 

The disruption and damage caused by building hazards that 

are relatively simple and inexpensive to address is another 

noteworthy observation. Many measures can be implemented 

for private dwellings by the owners if appropriate information is provided on what can be done, how to do it, and the 
D50 RECOVERY, MITIGATION, AND RECONSTRUCTION 

estimated costs and benefits of the actions. These simple 

measures include chimney reinforcement, attachment of older 

homes to their foundations, strengthening of cripple walls, 

and strapping of water heaters to prevent tipping. Bracing or 

tying down of equipment, building fixtures, and storage vessels are measures typically taken by businesses or government facilities. Some respondents believed that damage had 

been less in areas where such measures were popular or required; others said they wished they had done more to promote these measures. Some of those we interviewed noted 

the widespread damage to chimneys or problems with house 

anchoring and cripple-wall failure that was evident in 

postearthquake inspection records and commented that considerable damage could have been avoided if these measures 

had been implemented. 

The lesson learned here is particularly important to areas 

in the eastern United States where a greater proportion of the 

building stock is old and vulnerable to earthquake damage. 

Reinforcing an extensive stock of existing buildings susceptible to earthquake damage in a particular city may simply 

not be feasible in view of the enormous costs associated with 

it, whereas relatively simple measures may be very feasible 

and practical and still help considerably to reduce injuries 

and industrial disruption. Such measures also can serve to 

lessen the post-earthquake demands put on officials charged 

with disaster relief, building inspection, and repair requirements. 

Many communities in the San Francisco Bay Area that were 

spared damage in the Loma Prieta earthquake face the temptation of thinking that they are not vulnerable and therefore 

need take no further action. Are they really not vulnerable, or 

was the lack of damage related to specific characteristics of 

the earthquake which may not hold true next time? If the shaking from the Loma Prieta earthquake had lasted longer, would 

structures in areas subject to liquefaction have been damaged 

that were not damaged in that event? It is important for communities to critically assess the reasons why so little damage 

occurred and not be lulled into inactivity. Similarly, communities that were hard hit may feel that the problem has been 

solved for them. While to some extent this may be a valid 

conclusion, an earthquake on one of the other major faults, 

on an as yet unidentified fault, or with different attributes, 

may strike next time, leaving behind a new pattern of damage. 

Though a major lesson from the Loma Prieta earthquake 

concerned the influence of site characteristics on the type and 

extent of structural damage, the respondents did not emphasize the need to identify and address newly recognized hazardous areas. Some areas already required geotechnical review, but few respondents mentioned new efforts to establish 

such programs. As better maps become available that can 

delineate areas susceptible to such secondary consequences 

of earthquakes as liquefaction or landsliding, it will be easier 

to establish appropriate zones in which to regulate construction activity. Land-use regulation has traditionally been even 

more difficult to adopt than building codes, but more precise 

maps now provide for a wider variety of strategies to guide 

development in hazardous areas through nongovernmental 

institutions such as the banking and insurance industries. At 

the same time, this does not address the vulnerability of existing development already in these zones and the need for 

policies to deal with these potential problems. 

As shown by the pattern of response we received to the 

mail-out questionnaire, individuals responsible for various 

aspects of earthquake mitigation in local governments can be 

found in a wide variety of positions within a range of offices 

and agencies. Building officials, for example, are found in 

planning, public works, or fire departments, or in an independent department. Similarly, some agencies charged with 

disaster preparedness include mitigation activities within their 

scope of responsibilities while others do not. This has important implications for the provision of technical assistance by 

Federal, state, and regional programs, and for the assumptions they make about how to reach the appropriate audiences 

for particular types of information. The functions for which 

local agencies most need assistance in the implementation of 

mitigation programs must be identified so that technical assistance can be as useful as possible. 

The Loma Prieta earthquake was only a moderately strong 

earthquake that occurred in the most prepared state in the 

nation, yet it caused more than $8 billion in damage, most of 

which did not surprise persons knowledgeable about the hazard and the built environment in the region. At the same time, 

much of the region's development was relatively unscathed 

both because of the brevity of the shaking and because of 

actions taken by governments or individuals to prevent or 

lessen damage. Other parts of the Nation have done far less 

than the average California jurisdiction, for which the typical 

mitigation strategy has been to enforce its building codes and 

engage in some degree of public education about simple mitigation measures. The challenge is to find those measures best 

suited to individual communities and their pattern of vulnerability, based on the likely ability of the measures to reduce 

some significant portion of the local risk, and to devise strategies for supporting their implementation. 

ACKNOWLEDGMENTS 

The funds to support this project were provided by the U.S. 

Geological Survey through the National Earthquake Hazards 

Reduction Program (NEHRP) and administered by the National Science Foundation under Grant No. BCS-9003598. 

We would like to acknowledge the excellent cooperation we 

received from the many city and county officials and program representatives who willingly shared information and 

insights with us, either in interviews or by thoughtfully filling out the questionnaire. The opinions expressed in this report are those of the authors and do not necessarily represent 

those of the funding agencies or the respondents. 
LOCAL EARTHQUAKE MITIGATION PROGRAMS-PERCEPTIONS OF THEIR EFFECTIVENESS D5 1 

REFERENCES CITED 

Alesch, D.J., and Petak, W.J., 1986, The politics and economics 

of earthquake hazard mitigation-unreinforced masonry buildings in Southern California: Boulder: University of Colorado, 

Institute of Behavioral Science, Program on Environment and 

Behavior, Monograph 43,273 p. 

Association of Bay Area Governments, 1991, Macroeconomic 

effects of the Loma Prieta earthquake: Oakland, Calif., Association of Bay Area Governments, 48 p. 

Bay Area Earthquake Study, 1984, Earthquake preparedness in the 

San Francisco Bay region-an inventory and assessment^of 

current programs and activities and recommendations for 

future comprehensive earthquake preparedness projects (with 

appendices): Berkeley, Calif., Bay Area Earthquake Study. 

Beatley, Timothy, and Berke, Philip, 1990, Seismic safety through 

public incentives-The Palo Alto Seismic Hazard Identification Program: Earthquake Spectra, v. 6, no. 1, 

p. 57-79. 

Berke, Philip, and Wilhite, Suzanne, 1988, Local mitigation 

planning response to earthquake hazards-results of 

a national survey: College Station, Texas A&M University Center for Hazard Reduction and Community Rehabilitation, 38 p. 

Blair-Tyler, Martha, and Gregory, Penelope, 1988, Putting seismic 

safety policies to work: Oakland, Calif., Bay Area Regional 

Earthquake Preparedness Project, 40 p. 

California Seismic Safety Commission, 1985, A review of the seismic safety element requirement in California: Sacramento, 

Calif., California Seismic Safety Commission, Report 

SSC-85-05. 

1990, Status of California's unreinforced masonry building 

law, Annual Report to the Legislature: Sacramento, Calif., California Seismic Safety Commission, Report SSC-90-03. 

1991, Loma Prieta's call to action: Sacramento, Calif., California Seismic Safety Commission, 97 p. 

Drabek, T.E., Mushkatel, A.H., and Kilijanek, T.S., 1983, Earthquake mitigation policy-the experience of two states: Boulder, University of Colorado, Institute of Behavioral Science, 

Program on Environment and Behavior, Monograph 37,238 p. 

Earthquake Engineering Research Institute, 1990, Loma Prieta earthquake reconnaissance report: Earthquake Spectra, v. 6, Supplement, 448 p. 

Federal Emergency Management Agency, 1984, National Earthquake 

Hazards Reduction Program, five-year Plan-fiscal years 1985- 

89: Washington, D.C., Federal Emergency Management 

Agency, 130 p. 

1988, National Earthquake Hazards Reduction Programfiscal year 1988 activities: Washington, D.C., Federal Emergency Management Agency, Report to the Congress, 180 p. 

1990, Hazard mitigation opportunities for California: Washington, D.C., Federal Emergency Management Agency, State 

and Federal Hazard Mitigation Survey Team Report for the 

October 17,1989 Loma Prieta Earthquake, California, FEMA845-DR-CA, 73 p. 

Mader, G.G., 1988, Geology and planning-the Portola Valley 

experience: Portola Valley, Calif., William Spangle and Associates. 

May, Peter, and Bolton, Patricia, 1986, Reassessing earthquake hazard reduction measures: Journal of the American Planning 

Association, v. 52, no. 4, p. 443-451. 

Real, Charles, 1984, Probabilistic long-term forecasts of major earthquakes in the San Francisco Bay region: Sacramento, California Department of Conservation, Division of Mines and Geology, 38 p. 

Working Group on California Earthquake Probabilities, 1990, Probabilities of large earthquakes in the San Francisco Bay region, 

California: U.S. Geological Survey Circular 1053,5 1 p. 
THE LOMA PRIETA, CALIFORNIA, EARTHQUAKE OF OCTOBER 17,1989: 

SOCIETAL RESPONSE 

RECOVERY, MITIGATION, AND RECONSTRUCTION 

REBUILDING AFTER THE EARTHQUAKE IN AREAS OF GROUND 

FAILURE, SANTA CRUZ MOUNTAINS SUMMIT AREA 

By Martha Blair Tyler and George G. Mader 

Spangle Associates, Portola Valley, Calif. 

CONTENTS Page 

Abstract. ........................................................................ Introduction.. ................................................................. Setting.. ................................................................... 

Geologic review ...................................................... Rebuilding after the Loma Prieta earthquake.. .............. Hazard mapping ...................................................... Rebuilding policy .................................................... Administration of rebuilding ................................... Conclusions.. ................................................................. Acknowledgments.. ....................................................... References Cited ........................................................... 

ABSTRACT 

The Loma Prieta earthquake was centered in a sparsely 

developed residential area near the summit of the Santa Cruz 

Mountains in Santa Cruz County. Ground shaking and disturbance in this epicentral area were severe, damaging many 

houses. At the time of this study, two years after the earthquake, summit area homeowners were still locked in a battle 

with County officials for permits to repair or rebuild their 

homes. The County insisted that without geologic studies that 

conclude the sites are safe places to rebuild, no permits could 

be issued in areas with evidence of earthquake-caused ground 

failure. The owners claimed willingness to assume all risks 

and pressed to get on with their disrupted lives. In the meantime, the Army Corps of Engineers was in charge of FEMAfunded geologic studies of the summit area to determine the 

causes of ground cracking and the potential for future movement. 

Immediately after the earthquake, Santa Cruz County began very general mapping and applied strict rules for repair 

and rebuilding permits in the most hazardous areas. Over the 

following two years, the sizes of the hazardous areas were 

reduced as new information was generated and the rules gradually liberalized in response to both political pressure and new 

information. Preliminary conclusions from the Army Corps 

study then indicated that the earthquake had reactivated a large 

and deep ancient landslide in the summit area, but that it had 

little potential for rapid movement. The risk did not appear to 

be life threatening. Accordingly, the County moved toward 

applying geologic study requirements in effect before the 

earthquake to applications for repairs, rebuilding, and new 

development in the summit area. 

INTRODUCTION 

The most difficult questions about recovery and rebuilding 

after an earthquake arise when damage has been caused by 

ground failures-landslides, debris flows, surface fault ruptures, and other surface failures from liquefaction, lateral 

spreading, settlement, and related phenomena. The questions 

are similar whether the ground failures are caused by an earthquake or by some other cause. Geologic investigations are 

usually required to determine if it is safe to repair or rebuild. 

These investigations are often extensive, expensive, time-consuming, and controversial, and sometimes they are inconclusive. Under current disaster relief procedures, responsibility 

for the cost of such studies is not clear. The stakes are high: if 

studies show that future failures are likely, local governments 

may have little choice but to prohibit all repair and rebuilding in the area. This is not a decision that can or should be 

made without the best available information. No local political body wishes to add to the losses its constituents have already suffered in an earthquake. 

In the Loma Prieta earthquake, ground failures of uncertain origin and significance occurred in the Santa Cruz Mountains near the epicenter. The authors believe that by recording the sequence of decisions about repairs and rebuilding in 

this case, much may be learned that would help other jurisdictions having to deal with ground failures in the future. We 

also offer suggestions to help Federal and state disaster-response systems deal more effectively with this aspect of recovery after earthquakes. 
San 

RECOVERY. MITIGATION, AND RECONSTRUCTION 

* Lorna Prieta earthquake epicenter 

-- - County boundaries 

- Faults 

0 10 MILES 

LA 

Figure 1.-San Francisco Bay region, showing the location of the epicenter of the Lorna Prieta 

earthquake in the Santa Cruz Mountains of Santa Cruz County. 
REBUILDING AFTER THE EARTHQUAKE IN AREAS OF GROUND FAILURE D55 

SETTING 

The epicenter of the Loma Prieta earthquake is in Santa 

Cruz County, and the County suffered widespread damage in 

that earthquake. Sandwiched between the north shore of 

Monterey Bay and the crest of the Santa Cruz Mountains (see 

fig. I), the County includes the rugged western slopes of the 

mountains, which are forested and incised with deep, narrow 

valleys dropping down to the coastal terrace and ocean cliffs. 

Most of Santa Cruz County's population live and work on 

the coastal terrace. Broad beaches, sunny weather, and good 

accessibility attract vacationers, retirees, tourist-serving businesses, and an increasing number of electronics firms. The 

fertile coastal terraces support a significant agricultural industry and the redwood forests in the Santa Cruz Mountains 

sustain declining, but still important, lumbering operations. 

Since the 1960's, a large student population has been added 

with the opening of a campus of the University of California. 

Development in the rugged mountains has been sparse 

and for many years consisted mainly of small settlements 

and cabins used as second homes. However, the pressure to 

build in the mountains has increased in recent decades. Santa 

Cruz County is just over the hill from Santa Clara County's 

bustling "silicon valley," center of the San Francisco Bay 

region's high-technology industry. With the chronic and 

growing shortage of reasonably priced housing near the hightechnology jobs, commutes have lengthened and Santa Cruz 

County now faces increasing pressure to house people who 

work elsewhere. 

From 1980 to 1990, the County's population grew from 

186,100 to 228,700-an increase of 23 percent-in spite of a 

system of planning procedures and regulations designed to 

control growth (State of California, 1980, 1990). Less than 

half the County's population (43 percent) is concentrated in 

the four incorporated cities of Santa Cruz, Watsonville, 

Capitola, and Scotts Valley; the majority (57 percent) is scattered throughout its unincorporated areas including the Santa 

Cruz Mountains. 

GEOLOGIC REVIEW 

Santa Cruz County adopted a geologic hazards ordinance 

in 1975 to implement policies in the seismic safety element 

of its general plan (see County of Santa Cruz, 1985) and to 

meet the requirements of the Alquist-Priolo Special Studies 

Zones Act (State of California, 1972). The ordinance requires 

an assessment of geologic hazards before approval of any 

application for new development in areas mapped as hazardous. In Santa Cmz County mapped hazard areas include floodplains, coastal bluffs, landslide areas, and fault zones. If the 

assessment indicates hazards potentially affecting the proposed development, County staff can require additional 

geotechnical studies. The requirement pertains to fault zones 

designated by the California Division of Mines and Geology 

under the Special Studies Zones Act and also to county-designated fault zones. Potential landslide areas are designated 

on a map of landslide deposits at a scale of about 1:20,000 

prepared in 1975 for the seismic safety element (Cooper, Clark 

and Associates, 1975). 

REBUILDING AFTER THE LOMA PRIETA 

EARTHQUAKE 

In the aftermath of the earthquake, Santa Cruz County found 

itself in a very difficult situation. Ground near the summit of 

the mountains in the vicinity of the epicenter was obviously 

disturbed. Open fissures, buckling, and cracks were evident 

at many locations in the area. The cause of the cracks and 

their significance were not obvious. A massive landslide on 

Highway 17 in the mountains temporarily cut off access to 

the coast from the Santa Clara Valley. Houses, many seriously damaged and some beyond repair, were scattered 

throughout the area of ground disturbance (see figs. 2, 3). 

The sequence of actions taken by the County in addressing 

the repair and rebuilding of homes in this area is outlined in 

table 1 and described in the following sections. 

HAZARD MAPPING 

Santa Cruz County's response to the earthquake was immediate. County and consulting geologists were in the summit area right away, mapping the cracks and other evidence 

of disturbance. By October 23, six days after the earthquake, 

geologists from the U.S. Geological Survey (USGS), California Division of Mines and Geology (CDMG), and Santa 

Cruz County, together with local private geologists, had prepared a map delineating an area that had heavy damage and 

evidence of ground failure. Called the "red zone," this area 

formed a broad band between the San Andreas and Zayante 

Faults (see fig. 1). Areas within the "red zone" having the 

greatest indications of ground failure were also delineated on 

the map and labeled "areas of critical concern" (fig. 4). 

Early policy decisions about repairs and rebuilding were 

based on this initial map and subsequent refinements. Geologists were, however, uncertain about the cause and significance of the ground cracks. Some could be surficial and of 

little importance; others could be expressions of an unusual 

pattern of fault rupture associated with movement on the San 

Andreas fault; still others seemed more like evidence of deep 

landsliding. Some geologists feared that the earthquake had 

reactivated a huge ancient landslide that might continue to 

move. 

The County was in a dilemma about whether to permit rebuilding in the area affected by ground deformation without 

additional information. In November 1989, the Federal Emergency Management Agency (FEMA) allocated $600,000 to 

the U.S. Army Corps of Engineers for comprehensive geologic studies of the epicentral area. The Corps in turn con- 
D56 RECOVERY; MITIGATION, AND RECONSTRUCTION 

traded with consultants familiar with the geology of the Santa 

Cruz Mountains to study the causes of the ground failures 

and the potential for renewed movement (see fig. 5). In December 1989, a Technical Advisory Group (TAG) was formed 

to oversee the geologic studies. The TAG included representatives from the Corps of Engineers, USGS, and CDMG, as 

well as the Santa Cruz County geologist and two local geologists-one a professor at the University of California at Santa 

Cruz and the other a consultant. The latter two had been retained over the years by the County to review geologic reports submitted with development applications and were familiar with the local geology. 

Two years after the earthquake, the studies were still underway and the process had been very controversial. In effect, many residents in the area were prevented from repairing or rebuilding damaged homes until studies were 

completed. Their desire to rebuild and begin to normalize 

their shattered lives was far stronger than their concern about 

uncertain, future ground failures. They filled in ground cracks, 

refused geologists access to their properties and water wells 

for data, and fought on every possible level any geologic interpretation that would define their properties as unsafe. They 

impugned the impartiality of the TAG and the study process 

and insisted on having a representative attend the closed meetings. An engineering geologist representing the homeowners 

was eventually added to the TAG-a decision that led to the 

resignation of its chairman and another member, who believed 

that good science could not result from what was becoming 

essentially a political process. 

After almost two years and the expenditure of $1.45 million in FEMA funds (article in Santa Cruz Sentinel, June 4, 

1991), the studies began to clarify a very complex geologic 

situation. In February 199 1, two draft reports were released 

with tentative conclusions. Summit area residents, however, 

questioned the data, the process, and the conclusions. In June 

199 1, TAG released a preliminary map of surface cracks believed to be related to ground movement and held a public 

hearing to give residents a chance to correct any misinformation. In August, summit area homeowners presented their own 

study to the County Board of Supervisors. This study, prepared by engineers, geologists, and scientists in their group, 

disagreed with the hypothesis of the ancient landslide, instead attributing the surface cracks to tectonic movements. 

The Corps of Engineers studies were being reviewed by 

independent specialists who had not been involved in the studies up to that time. The preliminary conclusion of the Corps 

studies was that the earthquake had reactivated an ancient 

and deep landslide, causing many of the arc-shaped cracks in 

the summit area. However, the landslide, if it moves again, is 

expected to move slowly and is not considered life threatening. After the independent review and public comment, a final report was to be released in December 1991 at the earliest. The Santa Cruz Sentinel (May 5, 1991) commented: 

'Until the findings of the investigation are released, hundreds 

Figure 2.-Structure damaged by vertical movement on ground crack, Summit Road area, Santa Cruz Mountains, 

October 1989. 
REBUILDING AFTER THE EARTHQUAKE IN AREAS OF GROUND FAILURE D57 

of Summit homeowners remain in limbo, unable or unwilling to rebuild until the County receives conclusive data evaluating geologic risks in the mountains." 

REBUILDING POLICY 

Within a week of the earthquake, the Board of Supervisors 

passed an emergency ordinance amending the County's 1975 

Geologic Hazards Ordinance, which originally pertained only 

to new development in areas designated as potentially hazardous, to make it applicable to repair and rebuilding of houses 

and accessory structures in areas of ground failure (County 

of Santa Cruz, 1989). The amendment gave the Planning 

Department the authority to require geologic investigations 

before issuing permits to repair or rebuild structures in the 

"areas of critical concern." The initial policy was to prohibit 

repairs to structures in these areas if damage exceeded 50 

percent of the value of the structure. Buildings in the areas of 

critical concern with damage less than 50 percent could be 

Figure 3.-Damaged house with ground cracking and deformation 

in foreground, Santa Cruz Mountains, October 1989. 

repaired, provided studies showed no significant geologic 

hazards. 

One month after the earthquake, the 50-percent limitation 

was removed. Reconnaissance mapping completed by the 

USGS and the CDMG had by then allowed better delineation 

of areas likely to suffer further ground failure. With the removal of the 50-percent restriction, permits could be issued 

for repair or rebuilding of any structure in the areas of critical 

concern if geologic studies indicated favorable conditions at 

the local site. 

However, engineering geologists retained by home-owners to conduct site investigations in the areas of critical concern found it very difficult to conclude that hazards were not 

significant, because the regional studies undertaken under the 

Army Corps of Engineers were not yet completed. The site 

reports were therefore often inconclusive, citing the need to 

wait through at least one real rainy season to determine the 

potential for further ground failures. With the area in the midst 

of its fourth consecutive drought year, nobody knew when 

enough rain would fall to provide a test. Owners of damaged 

houses thus found themselves stymied. With inconclusive 

geology reports, they were unable to obtain permits and often found it impossible to get financing to make repairs. They 

began to pressure the Board of Supervisors for relief. 

The Board responded by adopting Ordinance 4048 in January 1990 (County of Santa Cruz, 1990). This ordinance permanently amended the geologic hazards ordinance to cover 

repair and reconstruction of damaged houses and accessory 

structures in areas of earthquake-induced ground failure. It 

also established that permits for repairs and rebuilding could 

be issued under the following conditions: 

a. The Planning Director determines on the basis of a geologic assessment or report of the dwelling site that any 

significant geologic hazard can be mitigated to an acceptable level of risk. For the purposes of this section, 

a potential risk associated with ground failure resulting 

from the October 17,1989 earthquake shall be regarded 

as an acceptable risk if it can only be evaluated by monitoring over time, and it does not present an immediate 

threat to life or of significant personal injury to persons 

residing on the subject property. 

b. The Board of Supervisors has not determined that the 

area in which the dwelling is located is unsafe to occupy. 

c. The owner records a Declaration of Geologic Hazards 

with the County Recorder which describes the potential geologic hazards from any on-site or off-site geologic conditions, the level of prior geologic investigation conducted, and any geoglogic investigation in 

progress, and which includes an agreement by the owner 

to assume all risks, waive all claims against the County, 

and indemnify and hold the County harmless from any 

claims arising from the issuance of the permit or from 

any alleged inadequacy of geologic investigation or 

geologic monitoring of the area in which the property 
RECOVERY, MITIGATION, AND RECONSTRUCTION 

Table 1 .-Chronology of the rebuilding process in Santa Cruz County after the Lorna Prieta earthquake, 

1989-1991 

Year Month Event that occurred or action that was taken 

1989 October 

November 

December 

1990 January 

August 

September 

December 

199 1 January 

February 

June 

July 

August 

Sep ternber 

Lama Prieta Earthquake 

Initial map of "red zone" and "areas of critical concern" completed. 

County offices opened to issue building permits for repair of earthquake damage. 

Geologic Hazards Ordinance amended to cover repairs and reconstruction in 

addition to new construction. 

Planning Department prohibited repair and reconstruction of buildings damaged 

more than 50 percent of value in "areas of critical concern." 

FEMA provides $600,000 to the Army Corps of Engineers for studies of the 

ground failures. 

Board of Supervisors allows building permits in "areas of critical concern" if 

damage over 50 percent. 

Board of Supervisors adopts 45-day moratorium on new construction in "areas of 

critical concern." 

Technical Advisory Group (TAG) established to oversee regional geologic studies 

of surnmi t area. 

Moratorium on new construction in "areas of critical concern" extended to 

November 1990. 

Summit homeowners "angrily demand that they be allowed to make necessary 

repairs at their own risk." (Santa Cruz Sentinel, January 9, 1990) 

FEMA-funded Earthquake Recovery Division opens. 

Geologic hazards ordinance amended to permit repairs and rebuilding pending 

geologic studies, if owners sign waivers. 

Board of Supervisors orders review of procedures. Supervisor Keely states, "The 

abundance of caution has instead become an impediment. There is this obsession 

with the geology that does not seem to be borne out by the facts." (Santa Cruz 

Sentinel, August 29, 1990) 

Geologic Hazards Ordinance amended to exempt repair applications from geologic 

study requirements when the repairs cost less than 50 percent of the value of the 

structure. 

Summit homeowners file class action lawsuit protesting waivers. 

County staff resumes issuing building permits for earthquake repairs and 

rebuilding. Fees reinstated. 

Draft TAG report released with tentative conclusions. 

Public hearing held on a preliminary map of cracks in the summit area. 

Earthquake Recovery Division disbanded after processing more than 7,600 

permits. 

Moratorium on new construction in "areas of critical concern" expires. 

Preliminary geologic study report indicates no significant hazard to life from 

geologic instability in summit area. 

Waiver requirements and procedures for rebuilding in "areas of critical concern" 

eased. 
REBUILDING AFTER THE EARTHQUAKE IN AREAS OF GROUND FAILURE D59 

is located by the U.S. Army Corps of Engineers or the These new provisions opened the door for repairs and reCounty. By such declaration the permittee shall ex- building in the most hazardous areas, but owners were still 

pressly agree that the issuance of said permit shall not required to submit geologic or geotechnical reports evaluatpreclude the County of Santa Cruz or any other agency ing site-specific conditions not requiring long-term monitorfrom determining in the future that the property which ing. The January 1990 ordinance did not affect new construcis the subject of said permit, or any structure or im- tion, and the approximately 500 vacant parcels in the areas of 

provement thereon, is unsafe to occupy and requires critical concern remained under the building moratorium esrepair, vacation, demolition, or abatement. The permit- tablished the previous November (County of Santa Cruz, 

tee shall further agree by said Declaration to waive any 1989). 

claim against the County for any losses to any improve- The County planning staff had recommended against the 

ments authorized by said permit which are later duly new waiver provisions, arguing that they would expose people 

ordered demolished or abated. and property to significant risks. The staff felt that the waiver 

0 

u 

1 2 3 4 5 MILES 

Sari Matoo County 

Ben Lomond 

SANTA CRUZ COUNTY Watsonville 

0 AREA OF HIGH DAMAGE 

/ / / RED ZONE 

r""-) . .. AREA OF CRITICAL CONCERN Monlerey Bay 

Monterev Coin 

Figure 4.-Map prepared by informal consortium of Federal, State, County, and private geologists in the first week after the Loma Prieta 

earthquake, showing the "red zone" (encompassing the areas of considerable damage and ground failure), areas of high damage, and the 

"areas of critical concern" (where the greatest indications of ground failure were found). 
D60 RECOVERY, MITIGATION, AND RECONSTRUCTION 

procedure required making judgments about geologic safety 

without full geologic information. However, the Board was 

under strong pressure from owners of damaged property and 

considered the waiver provisions a responsible compromise. 

These changes did not, however, satisfy property owners 

in the summit area, who continued to press for more relief 

from the the geologic report requirements. In September 1990, 

the Board once again amended the Geologic Hazards Ordinance. This time, the definition of a project subject to the 

geologic study requirements was changed to exempt repairs 

and improvements costing less than 50 percent of the value 

of the structure. This change allowed many repair projects in 

the area of critical concern to proceed without any geologic 

review. Property owners were still required to sign waivers 

holding the County harmless in the event of future damage or 

of County decisions affecting the use of the 

The system of requiring geologic reports for major projects 

and waivers for almost all projects continued until the fall of 

1991. Because the regional geologic studies were still ongoing and a rainy season passed without significant rainfall, 

property owners continued to find it almost impossible to 

obtain conclusive geologic reports and get financing for major repairs and rebuilding. Financial institutions did not like 

the waivers, particularly the one permitting the Planning Department to later order demolition of buildings found 

to be unsafe without compensation to owners. More than 100 

summit area property owners joined in a class action lawsuit 

to overturn this waiver requirement. 

In September 1991, after preliminary results from the regional studies indicated that there was little threat to life from 

geologic hazards in the summit area, the Board of Supervisors further relaxed the rebuilding requirements and took steps 

to streamline the procedures for obtaining permits. The provision of the January 1990 Ordinance (Ordinance 4048) giving the County unrestricted power to order demolitions was 

rescinded, responding to a major objection by property owners. Time limits were set for the official review of permit 

applications and for responding to geologic reports. Channels of communications, particularly with applicants' geologists., were simplified. 

During all this time, little actual rebuilding had taken place 

in the summit area. Ordinance 403 1, which the Board of Supervisors had adopted in November 1989, established a 45- 

day moratorium on new development in the areas of critical 

concern (County of Santa Cruz, 1989). This moratorium was 

periodically renewed until July 3 1, 199 1, when it was allowed 

to expire. At that time, Planning Director Dianne Guzman 

noted that "existing procedures for geologic review and inFigure 5.-Geologic trenching in area of ground cracking, near Summit Road, Santa Cruz Mountains, viewed here by 

participants at the International Symposium on Rebuilding After Earthquakes, Stanford University, August 1990. 
REBUILDING AFTER THE EARTHQUAKE IN AREAS OF GROUND FAILURE D6 1 

formation from the upcoming TAG report provide sufficient 

assurance that new building will be appropriately regu-lated 

to avoid the consequences of geologic hazards" (quoted in 

the Santa Cruz Sentinel, July 3 1, 1991). 

ADMINISTRATION OF REBUILDING 

After the earthquake, very complex policy issues regarding rebuilding demanded time and attention from both County 

staff and the Board of Supervisors. These demands occurred 

at a time when the normal administrative demands also increased dramatically. 

Less than a week after the earthquake, County planning 

and building offices reopened. However, they accepted applications for building permits only for repair of earthquake 

damage; no other permit applications were accepted. The staff 

estimated that earthquake damage would lead to 4,000 permit applications requiring about 48,000 hours of staff time to 

process. The County therefore proposed, and FEMA agreed 

to fund, the hiring of a private consultant, Wildan Associates, 

to handle all building permit applications for repairing earthquake damage (oral communications from Pete Parkinson, 

Santa Cmz County Planning Department, June 1990). 

The Earthquake Recovery Division (ERD), staffed by 

Wildan and funded by FEMA, opened in January 1990 in a 

separate building across the street from the County building. 

It operated with a staff of 22, including 7 inspectors, 4 code 

enforcement officers, 4 plan checkers, 4 plan intake persons, 

and 3 clerks (oral communication from Glen Parrot, head of 

ERD, June 1990). Wildan assembled the staff from around 

the State and also contracted with a geotechnical firm to review permit applications and geologic reports. County staff 

familiar with building inspection, demolitions, environmental planning, and planning were assigned to the ERD to ensure coordination with regular County operations. The County 

staff then resumed processing applications for permits not 

related to earthquake damage. 

In March 1990, five months after the earthquake, the ERD 

was still processing more than 100 building permits and conducting more than 300 inspections per week (Glen Parrot, 

oral communication, June 1990). Because ERD staff expenses 

were covered by FEMA, the normal building permit fees were 

waived. In January 1991, regular County staff took over the 

processing of permit applications for earthquake repairs and 

rebuilding, and the building permit fees were reinstated, but 

with a six-month grace period of free inspections on projects 

already in the system. The ERD continued conducting inspections until July 199 1, when it was disbanded altogether. 

At that time, about 3,000 repair applications were still in the 

process. During the 18 months of its operation, the ERD had 

processed more than 7,600 permits and made thousands of 

inspections. Federal reimbursements for the effort exceeded 

$7 million. 

Wildan personnel contend that geologic review was the 

most difficult and time-consuming part of the permitting process. They established an objective of processing all permits 

within 4 to 5 days, but they were not able to do so in cases 

requiring geologic review. Most of the complaints about the 

process from applicants centered on the time and expense 

needed to meet the geologic requirements (oral communications from Kevin Powers of Wildan Associates and Glen Parrot, head of ERD, June 1990). 

CONCLUSIONS 

Role of County Planning Staff..-The Santa Cruz County 

planning staff consistently held to the position that repairs 

and rebuilding in the areas of critical concern should not occur until geologic studies were completed. When studies 

showed less risk than originally feared, staff recommended 

easing restrictions. Although opponents of the staff position 

suggested that "no growth" politics influenced the position, 

we found no confirming evidence. Nor did concerns about 

either liability or "taking" of property by the County without 

compensation appear to have been major factors. As far as 

could be judged from various articles and discussions published in the Santa Cmz Sentinel during the period 1989- 1991, 

the position seems to have stemmed almost entirely from the 

staff's concept of their role in protecting public safety. 

Role of the Board of Supervisors.-The Board of Supervisors, more subject to pressure from constituents, compromised 

by permitting some repair and rebuilding on the condition 

that homeowners signed waivers. This was ultimately ineffective, because lending institutions were reluctant to lend 

money with the waivers in place. Eventually the waivers, created originally to give an additional option to homeowners, 

became the focus of opposition. 

The Role of FEMA.-After the earthquake, FEMA quickly 

authorized funds for a regional geologic study to evaluate 

potential ground failure problems. When such problems 

clearly transcend individual property boundaries, there is 

strong need for area-wide studies to establish the conditions 

for safe rebuilding. Not since the Alaska earthquake in 1964 

has the Federal Government been involved in hazard evaluations after a disaster as extensive and complex as those following the Loma Prieta earthquake. FEMA procedures for 

dealing with ground failures, however, are ad hoc. There is a 

need for a consistent policy that supports the local government in upholding public safety. 

Role of Owners of Damaged Homes.-At the political level, 

the summit-area homeowners maintained a single, consistent 

position. They wanted to repair and rebuild their houses and 

restore normalcy to their lives. For most homeowners, their 

home is their largest investment. They stand to lose everything if their property is declared unsafe. In Santa Cruz County, 

summit-area residents brought anger and deep emotion to the 

political process. Arguments for safety did not seem relevant 
D62 RECOVERY, MITIGATION, AND RECONSTRUCTION 

to them. Staff and political decisionmakers, charged with protecting public safety, were placed in an adversarial position 

to those they were trying to help. In fact, planners and geolo- 

' gists, not the geologic hazards, were seen by many property 

owners as the problem. 

Mapping Ground Failures.-The experience in the Santa 

Cruz Mountains and in Anchorage after the 1964Alaska earthquake demonstrates the value of rapid delineation of areas 

encompassing ground failures and potential ground failures, 

coupled with imposition of tight rebuilding restrictions in 

those areas. These measures allow rebuilding to proceed unimpeded in areas without potential hazards while pinpointing areas where additional studies are needed. As new information is developed, the areas of concern tend to be reduced 

and rebuilding restrictions can be eased. Given typical 

postdisaster politics, it is almost impossible to tighten restrictions as time passes after the disaster. 

Geologic Studies.-No earthquake victim wishes to wait a 

year or two for geologic studies to be completed before knowing if a home or other structure can be rebuilt. In reality, however, such studies may take a long time. Also, the results of 

even the most exhaustive studies are often not as conclusive 

as many would like. Qualified professionals can often differ 

on interpretations of geologic phenomena. It is very important to protect the integrity of the study process, while at the 

same time keeping it open enough that affected property 

owners and jurisdictions know what is being done. Professionals need more guidance in how to work out scientific and 

technical differences successfully in highly charged political 

contexts. 

Acceptable Risk.-Acceptable risk is not an abstraction. It 

is readily discerned from the pattern of public decisions. Santa 

Cruz County appears to be willing to accept the risk of property damage from slow-moving ground failure, but not risk 

to human life. Additionally, owners are more likely to be allowed to assume risks if their structures have minor damage 

than if they have major damage. People with existing houses 

in the summit area are generally permitted to accept more 

risk than those planning to build new houses in the area. Thus, 

although the general nature of acceptable risk is discernible, 

it is not necessarily a rational pattern. 

Waivers.-Waivers do not solve the problem of rebuilding 

in potentially unsafe areas. Although property owners may 

volunteer to assume liability so that their projects can move 

ahead, elected officials must look at public health and safety, 

potential liability for damage, and possible loss of public 

improvements serving private uses in unsafe locations. Financial institutions seem increasingly wary of making loans 

secured by property encumbered with waivers. In the end, a 

waiver does nothing to address the potential for future ground 

failures. In Santa Cmz County, the waiver provisions originally sought by the owners were soon considered to be as 

onerous as the geologic study requirements. 

Building Permits.-Practically all cities and counties are 

hard pressed to keep current with the normal processing of 

building permits. After an earthquake, when emergency repairs, major repairs, and reconstruction must be handled, the 

load can be more than doubled. This puts a stress on staff and 

requires difficult decisions in setting priorities and obtaining 

outside assistance. Santa Cruz County, with Federal assistance, engaged a private firm to take over processing of building permits related to the earthquake. This action separated 

the permit process for earthquake repairs and rebuilding from 

the normal permit process. Controversy centered on the relatively few cases in which uncertainty about geologic stability 

held up the granting of permits. Otherwise, the process was 

efficient, paving the way for the repair and rebuilding of earthquake-damaged structures throughout most of the County. 

Suggestions for Responding to Future Earthquakes.-The 

key to improving response to ground-failure hazards after an 

earthquake seems to lie in preplanning for the comprehensive geologic studies that will be required. This would involve clearly defining the responsibilities of Federal, State, 

and local agencies, as well as those of the property owners. 

Procedures for handling the increased load of building permit applications can also be worked out in advance. 

ACKNOWLEDGMENTS 

Work on this paper was partly supported by National Science Foundation grant (BCS-9025125). The authors assume 

full responsibility for the facts and conclusions set forth in 

this paper. 

REFERENCES CITED 

Cooper, Clark and Associates, 1975, Preliminary map of landslide 

deposits in Santa Cruz County, California: Cooper, Clark and 

Associates, Scale 1: 20,000. 

County of Santa Cruz, 1985, Chapter 16.10, Geologic Hazards, Section 16.10.010 - 16.10.130 (adopted in 1975,): Santa Cruz 

County Code, p. 16.1-16.23. -- 1989, Ordinance No. 403 1, Ordinance adding Chapter 16.11 

to the Santa Cruz County Code relating to a development morat;orium in areas of critical concern, adopted November 21,1989. -- 1990, Ordinance No. 4048, Ordinance amending Geologic 

Hazards Ordinance (Section 16.10.095 of the Santa Cruz 

County Code) regarding repair and reconstruction of damaged 

dwellings and accessory structures in areas of earthquake-rellated ground failure, adopted January 23, 1990. 

State of California, 1972, Public Resources Code, Division 2, Chapter 

'7.5, Alquist-Priolo Special Studies Zones Act of 1972. -- 1980: Department of Finance, Population Research Unit, 

Report 80 E-1, 9 pp. January 1, 1980. -- 1990: Department of Finance, Population Research Unit, 

Report 90 E-1 ,9 pp, January 1, 1990. 
THE LOMA PRIETA, CALIFORNIA, EARTHQUAKE OF OCTOBER 17,1989: 

SOCIETAL RESPONSE 

RECOVERY, MITIGATION, AND RECONSTRUCTION 

THE RESPONSE OF THE STATE OF CALIFORNIA 

TO THE LOMA PRIETA EARTHQUAKE 

By Charles C. Thiel Jr., Stanford University 

George W. Housner, California Institute of Technology, and 

L. Thomas Tobin, California Seismic Safety Commission 

CONTENTS Page 

Abstract.. ....................................................................... Introduction.. ................................................................. 

The Board of Inquiry on the Loma Prieta 

Earthquake.. ............................................... Earthquake-caused damage to transportation 

structures .................................................... 

Damage to the Bay Bridge ................................ The Cypress Viaduct collapse ........................... San Francisco freeway viaducts ........................ Collapse of the Struve Slough Bridge ............... Impacts on cross-Bay transportation ....................... Findings and recommendations of 

the Board of Inquiry ................................... 

For action by the Governor ................................ 

For action by the Director of 

the Department of Transportation.. ............ 

For action by transportation agencies 

and districts.. .............................................. Governor's questions.. ............................................. 

1. Why did the Cypress Viaduct of 

Interstate 880 and the Bay Bridge 

span fail in the earthquake? ....................... 2. Were these failures foreseen or 

could they have been foreseen? ................. 3. How may possible future bridge 

and structure failures be accurately 

predicted?. .................................................. 4. Did the schedule for and manner of 

retrofitting these structures properly 

utilize the seismic and structural 

information developed following 

other earthquakes in California? ................ 

5. Should the state modify the existing 

construction or retrofit programs for 

freeway structures and bridges in light 

of new information gained from this 

earthquake?. ............................................... 

6. Are California's freeways safe in 

earthquakes?. ............................................. State agency actions ...................................................... Common problems in agency response ............. Conclusions.. ................................................................. References cited ............................................................ Appendix-Executive Department, State of 

California, Executive Order D-86-90. ....... 

ABSTRACT 

A Board of Inquiry was appointed by the Governor of California to investigate the damage caused by the 1989 Loma 

Prieta earthquake, particularly to bridges and freeway structures. The Governor wanted to know not only what happened, 

but how to prevent such destruction in the future. The Board 

identified three essential challenges that must be met by the 

citizens of California, if they expect a future adequately safe 

from earthquakes: (1) ensure that earthquake risks posed by 

new construction are acceptable; (2) identify and correct unacceptable seismic safety conditions in existing structures; 

and (3) develop and implement programs that will foster rapid, 

effective, and economic response to and recovery from future damaging earthquakes. The Governor issued an Executive Order to implement the principal Board recommendations that all State-owned and State-operated structures are 

to be seismically safe and that important structures are to 

maintain their function after earthquakes. The California Seismic Safety Commission was directed to evaluate the response 

of State agencies to the Order. They found performance to be 

generally good, though variable. Inadequate funding is the 

most serious and most difficult problem for the agencies to 

address internally; also difficult are legislative capital budgeting processes that are cumbersome. Agencies were encouraged to make individual administrators responsible for seismic safety to ensure management accountability, in place of 

the generally diffuse responsibility now found in most agen- 
D64 RECOVERY, MITIGATION, AND RECONSTRUCTION 

cies. The Board, Governor, and Commission all concluded 

that while much progress had been made during the previous 

two decades in reducing earthquake risks, much more awaits 

doing. More aggressive efforts to mitigate the consequences 

of inevitable future earthquakes are needed if one of the most 

fundamental of responsibilities of government is to be fulfilled-to provide for the public safety. The Loma Prieta earthquake should be considered a clear and powerful warning to 

the people of California. Earthquakes respect our actions, not 

our intentions. 

INTRODUCTION 

The Governor of California signed an Executive Order on 

June 2, 1990, that may prove to be the most significant step 

to improve seismic safety taken by the State in the last several decades. Executive Order 86-90 for the first time sets the 

policy that all State-owned and State-operated ~~tructures are 

to be seismically safe and that important structures are to 

maintain their function after earthquakes. This is a marked 

departure from responses to past earthquakes, where actions 

tended to focus on the type of facility that failed. The full text 

of the Executive Order is reproduced in the appendix. The 

Order was a direct consequence of the recommendations and 

findings contained in the report of the Board of Inquiry on 

the Loma Prieta Earthquake of 1989 (Housner and others, 

1990). 

The language of the Executive Order is simple and direct. 

The Governor required the Department of Transportation in 

particular, and all other California State agencies in general, 

to use generally accepted earthquake resistant codes and to 

seek external evaluations of compliance. The effect of external scrutiny should not be underestimated as a tool to obtain 

better seismic design and construction. Early indications were 

that implementation of this Executive Order would substantially improve the seismic resistance of transportation structures and State buildings. The Order also directed the Seismic Safety Commission to review actions by State agencies 

in response to the directions of the Order and to report to the 

Governor on their actions. The Commission issued its report 

to the Governor on agency response on November 30, 1990. 

The Commission found agency actions to be generally positive, but with substantial differences in approach among them 

(Seismic Safety Commission, 1990). 

This paper is divided into two parts. The first part reviews 

the findings and recommendations of the Board of Inquiry; 

the second presents the Seismic Safety Commission's review 

of the actions taken by the State agencies in response to the 

Governor's Executive Order 86-90. This paper integrates 

materials presented in Housner and Thiel (1990) and Thiel 

and others (1991). It represents actions that had been taken 

through 1990. In the intervening period much has been done. 

Caltrans has undertaken a massive, publicly financed program 

to retrofit many bridges. The more substantial of these investments, particularly for the San Francisco-Oakland (Bay 

Bridge) and Golden Gate toll bridges, is currently being debated (1996). 

THE BOARD OF INQUIRY ON THE LOMA 

PRIETA EARTHQUAKE 

In November 1989 Governor George Deukmejian of California appointed an independent Board of Inquiry to report 

on the October 17,1989, Loma Prieta earthquake. The Board 

consisted of George W. Housner, Chairman, Joseph Penzien, 

Vice Chairman, Mihran S. Agbabian, Christopher Arnold, 

Lemoine V. Dickerson, Jr., Eric Elsesser, I. M. Idriss, Paul C. 

Jennings, Walter Podolney, Jr., Alexander C. Scordelis, and 

Robert E. Wallace. John F. Hall served as Technical Secretary, and Ben Williams served as administrative officer in 

support of the Board; Charles C. Thiel, Jr., served as the technical writer and editor of the Board's report. The formation 

of the Board of Inquiry was prompted by earthquake damage 

to bridges and freeway structures and by the desire to know 

not only what happened, but how to prevent such destruction 

in future earthquakes. The Governor charged the Board with 

reporting on the causes of damage and what implications these 

findings might have on the California highway system 

(Deuk:mejian, 1989). 

The Board gathered its information from presentations by 

State Department of Transportation (Caltrans) employees and 

independent experts in seismology, structural engineering, 

geotechnical engineering, and other disciplines. Most of the 

information was presented at public hearings held in Sacramento, the San Francisco Bay Area, and Southern California. 

Testimony was also invited from the public. Reports and written information were sent directly to Board members for their 

review. The Board held seven public meetings between November 1989 and March 1990 at which 70 individuals provided testimony. Board members also toured the collapsed 

Cypre,ss Viaduct structure in Oakland and several of the damaged San Francisco viaduct structures. 

EARTHQUAKE-CAUSED DAMAGE TO TRANSPORTATION STRUCTURES 

The Loma Prieta earthquake in October 1989 occurred near 

three large modem cities in central California-San Jose, San 

Francisco and Oakland. Thirteen State-owned and five locallyowned bridges were closed to traffic following the earthquake, 

very small numbers considering that there are over 4,000 

bridges in the area. Forty-one people died in the collapsed 

Cypre:ss structure, and one died on the San Francisco-Oakland I3ay Bridge in an automobile accident moments after 

the earthquake. The cost of the earthquake to the transportation system was estimated at $1.8 billion, of which damage 

to State-owned viaducts totaled about $200 million and damage to other State-owned bridges was about $100 million. 
THE RESPONSE OF THE STATE OF CALIFORNIA TO THE LOMA PRIETA EARTHQUAKE D65 

The impacts of the earthquake were much more, however, 

than the loss of life and direct damage. The Bay Bridge is the 

principal transportation link between San Francisco and the 

East Bay (see fig. 1). It was out of service for a month, and 

use of alternative routes caused substantial hardship to individuals and businesses. 

Only a small percentage of the bridges in the area sustained 

any earthquake damage at all. Most of the bridges damaged 

in this earthquake were built before construction standards 

were stiffened in the 1970's to reflect lessons learned in the 

197 1 San Fernando earthquake. The greatest damage during 

the Loma Prieta earthquake occurred to older bridge structures sited on soft ground. 

Throughout California, Caltrans currently maintains 1 1,287 

highway and pedestrian bridges with spans greater than 20 ft, 

a number almost identical to the 1 1,229 bridges maintained 

by California local governments in the State. Caltrans District 4, whose jurisdiction approximates the area of greatest 

earthquake damage, is responsible for 1,896 State bridges, of 

which 91 (4.8 percent) incurred some degree of damage 

(mostly minor) during the earthquake. At only 13 bridges was 

structural damage or the potential threat to public safety sufficiently serious that they were closed to traffic for some period of time. 

The most tragic impact of the earthquake was the loss of 

life caused by the collapse of the Cypress Viaduct. The greatest disruption was caused by the closure of the Bay Bridge 

for a month while it was repaired, leading to costly commuting alternatives and significant economic losses. In addition, 

some of the steel rocker bearings supporting the navigator 

spans of the San Mateo-Hayward Bridge failed, but the bridge 

remained open. This could have led to catastrophic damage if 

earthquake shaking had been longer or more intense. 

On the other hand, only minor damage was incurred by the 

Golden Gate Bridge, which is founded on rock, and by the 

BART trans-Bay tube, which was specially engineered in the 

late 1960's to withstand earthquakes. A post-earthquake inspection of the Dumbarton Bridge, built during the 1980's 

Figure 1 .-Principal transportation links across San Francisco Bay. 
D66 RECOVERY, MITIGATION, AND RECONSTRUCTION 

with earthquake design criteria in mind, revealed no structural damage. 

Bridges maintained by local governments also incurred 

damage, though for none was it as catastrophic as for some 

of the Caltrans structures. A partial survey by Board of Inquiry staff found that at least 43 locally maintained structures 

in the area were damaged, of which at least 5 were closed to 

traffic for some period of time, but none collapsed. Reports 

from post-earthquake reconnaissance teams indicated that 

most local bridges performed remarkably well. 

DAMAGE TO THE BAY BRIDGE 

Design of the San Francisco-Oakland Bay Bridge was completed in 1933, and construction was finished in 1936. It consists of two sections-a West Bay crossing from San Francisco to Yerba Buena Island and an East Bay crossing from 

Yerba Buena Island to Oakland. The total distance along the 

alignment from the San Francisco anchor of the West Bay 

crossing to the easternmost Pier E39 of the East Bay crossing 

is 4.35 mi. The bridge is of double-decker design, with the 

upper deck carrying five lanes of traffic in the westerly direction and the lower deck carrying five lanes of traffic in the 

easterly direction. The lower deck had been originally designed for trains. 

The West Bay crossing consists of two suspension structures. Its total length is 1.95 mi. Both anchorages and the 

main supporting piers are founded on rock. The East Bay 

crossing consists of 4 shallow simple-span trusses on Yerba 

Buena Island, 1 long cantilever truss structure, 5 deep simplespan trusses, 14 shallow simple-span trusses, and a number 

of simple-span deck systems that use steel and concrete stringers supported on concrete bents (transverse supporting 

frames). The total length of the East Bay crossing is 2.14 mi. 

The Bay Bridge was designed for earthquake accelerations 

of O.lg (g is the acceleration due to gravity), comparable to 

the levels specified in the 1930 Uniform Building Code for 

buildings. Knowledge of actual ground motions in damaging 

earthquakes was very limited at that time; the first few measurements of strong ground motions were not made until the 

1933 Long Beach earthquake. In the 1970's some seismic 

strengthening of the Bay Bridge had been done through the 

installation of cable restrainers. 

The principal earthquake damage to the Bay Bridge was 

the failure of the upper and lower closure spans at Pier E9 of 

the east Bay crossing. These 50-foot-long upper and lower 

closure spans fell when the bolts failed that connected the 

pier to the 290-ft truss to the east (fig. 2). Bolts at connections of Piers El 8-E23 also failed. The span at Pier E23, close 

to the eastern edge of the bridge, was near failure of a comparable type to that of E9. The concrete pedestal bases of Pier 

El7 cracked when the pier rocked back and forth and incurred 

some damage at the corners. The Bridge was closed for one 

month for repair. 

The closure spans linking the two long-span trusses on either side of Pier E9 were supported on 5 in of bearing on 

seat-type expansion joints 6 in wide at the west end and by 

bolted connections at the east end. When the truss to the east 

broke free from its support, the closure spans were pulled 

with it, and the motions were large enough to slide them off 

the 5-in seats at the west end. As a result, the spans hinged 

down under gravity load, with the upper span coming down 

on the lower one, which hit an electrical housing before coming to rest on the west truss connection to the pier. 

The: level of ground shaking at the bridge site in the Loma 

Prieta earthquake was both of smaller intensity and shorter 

duration than that which can be expected in larger and closer 

earthquakes. Moreover, the duration was not sufficient to excite all the different modes of the Bay Bridge's response that 

are likely in a longer duration event, nor was the level of shaking sufficiently close to that expected in major earthquakes to 

test th~e strength of bridge elements. 

THE CYPRESS VIADUCT COLLAPSE 

The Cypress Viaduct was California's first continuous 

double-decker freeway structure, a design used again for several freeway viaducts in San Francisco, but not used anywhere 

else in the State. Each deck of the Viaduct carried four lanes 

of traffic. During the magnitude 7.0 Loma Prieta earthquake, 

a large portion of the Cypress Viaduct collapsed (fig. 3). This 

collapse, which took the lives of 41 people, was the most 

tragic consequence of the earthquake. Search and rescue operations continued for a week. Fortunately, traffic at the time 

of the earthquake was very light compared to the normal density for the middle of rush hour, because the televised third 

game of the World Series at Candlestick Park between the 

two local baseball teams had just started. Caltrans demolished and removed the standing portions of the structure and 

resurfaced the frontage roads within three months. 

Preliminary design of the Cypress Viaduct was began in 

1949 by Caltrans, and construction was undertaken between 

1954 and 1957, during a period when little was known about 

. . . . 0 5 10 'I~METERS 

- 0-0 FEET 

Figure 2.-Failure of the San Francisco-Oakland Bay Bridge in 

the Lorna Prieta earthquake. The upper and lower closure spans at 

Pier E89 fell when the bolts attaching the east truss-span were severed 

and it moved to the east, pulling the link spans off their western 

supports. 
THE RESPONSE OF THE STATE OF CALIFORNIA TO THE LOMA PRIETA EARTHQUAKE D67 

seismic design of reinforced concrete structures. It was one 

of the earliest uses of prestressed concrete in U.S. bridges. 

More significantly, the Cypress Viaduct was designed before 

research had developed procedures for achieving ductility in 

overstressed structural members; the columns and joints therefore failed in a brittle manner when overloaded. The Caltrans 

seismic design criteria in effect during 1949 to 1954, which 

had been introduced in 1943, stipulated only a seismic strength 

coefficient of 0.06g. 

The Cypress Viaduct was a reinforced concrete structure 

with some prestressing and two levels of elevated roadway. 

The box-girder roadway was supported by a series of 83 twostory bents. Forty-eight of these bents collapsed in the Loma 

Prieta earthquake-bents number 63 through 11 2, with the 

exception of Bents 96 and 97, which remained standing (the 

middle portion of fig. 3). A number of the bents had posttensioned concrete transverse girders at the top level. The 

Cypress design did not incorporate ductility, since this was 

not common until the 1970's. Longitudinal cable restrainers 

were installed in 1977 at all transverse joints in the box-girder 

bridge superstructure to provide continuity. The northern twothirds of the Cypress Viaduct, the major portion that collapsed, 

was founded on about 7 ft of dense to stiff artificial fill overlying a preexisting triangular tidal marsh composed of soft 

bay mud and old slough channels that parallel the west side 

of the viaduct structure. 

Failure occurred in the lower girder-to-column joints on 

both sides of a bent; the initial failure was in the short column 

stub above the top of the lower deck and below the shear key 

(fig. 4). The upper girder-to-column joint sometimes failed 

completely or was severely cracked. Almost all the damage 

in this upper joint, however, seems to have been produced as 

a result of the collapse of the upper deck onto the lower deck. 

Static and dynamic analyses and experiments performed 

on standing portions of the Cypress structure indicate that 

the calculated seismic demands on the structure during the 

Loma Prieta earthquake exceeded the level required to initiate failure in this nonductile structure. 

SAN FRANCISCO FREEWAY VIADUCTS 

The Loma Prieta earthquake caused only minor to moderate shaking at the San Francisco freeway viaduct sites. These 

viaducts (Embarcadero Freeway, Terminal Separation Viaduct, 

Central Viaduct, China Basin Viaduct, Southern Freeway Viaduct, and Alemany Viaduct; see fig. 5) were all built with the 

same technology used for the Cypress Viaduct and these were 

the only structures in the State of this design. With the exception of the Alemany Viaduct, all the San Francisco viaducts 

were damaged during the earthquake and subsequently closed 

to traffic. A contributing fact to their earthquake performance 

for some may be their location on filled ground or at the transition between natural and filled ground. 

The San Francisco freeway viaducts are composed of 

single-column and multicolumn bents, typically with two 

tiers of framing (rarely three) supporting two levels of roadway. The transverse lateral-load-resisting system in the 

multicolumn bents typically consists of pinned-base singlestory portal frames with one or more columns cantilevering 

to the upper level bent cap (girder). The reinforcement in 

the columns and girders of the bents was generally poorly 

detailed by current standards and reflects the engineering 

profession's lack of understanding regarding the inelastic 

response of reinforced concrete members at the time when 

these structures were designed. None of the six freeway structures had a planar lateral-load-resisting system in the longitudinal direction. A lack of redundancy and the inadequate 

reinforcement detailing are two of the major seismic deficiencies in these freeway structures. 

9th JUL 

T Bent 27 

Bents 45, 

I 

Bent 63 

o I KILOMETER Collapsed Portion 

I----, 

0 0.5 MILE 

To 

' Bay 

Bridge 

Figure 3.-The Cypress Viaduct double-decker freeway on Interstate 880 in Oakland, California, showing the extent of the collapse in the 

Loma Prieta earthquake. Location of selected bents (transverse frame elements) in the structure are shown for reference. Also identified are 

some of the roads and numbered streets in the part of Oakland traversed by the structure. 
D68 RECOVERY, MITIGATION, AND RECONSTRUCTION 

Damage to the individual viaducts in San Francisco varied 

and included shear cracking in columns, girders, and joints; 

torsional cracking in outrigger bents; anchorage failure of the 

girder reinforcement; and shear key failure, among others. 

Many of the crack patterns are similar to those observed in 

the collapsed and damaged portions of the Cypress Viaduct 

in Oakland. 

After the Loma Prieta earthquake, Caltrans retained six 

consultants to prepare contract documents for the upgrading 

of the six San Francisco viaducts. The criteria set by Caltrans 

for the development of the upgrading schemes included requirements for the analysis of the freeway structures' design 

and detailing requirements. The damage criterion accepted 

serious damage, but not collapse, during severe earthquake 

shaking. These designs were later reviewed by a Caltransappointed independent review panel, at the suggestion of the 

Board of Inquiry. 

COLLAPSE OF THE STRUVE SLOUGH BRIDGE 

The Struve Slough Bridge is located on California Highway 1 along the Pacific Coast between Watsonville and Santa 

A 

girder 

shear key !-+ 

5 I Seismic force 

bDGd 

7 

Figure 4.-Typical failure sequence of the common style of bent 

(B 1) in the Cypress Viaduct in the Loma Prieta earthquake (see fig. 

3). A, Bent before failure. B, Failure was initiated along a crack 

forming a plane of weakness in the joint region. Gravity and seismic 

forces then pushed the upper column down and away from the joint 

(C), resulting in the collapse of the upper deck (D), After Nims and 

others (1989). Of the 48 collapsed bents, 41 failed iin this way. 

Cruz,. It consists of side-by-side structures constructed in 1964; 

one structure carried northbound and the other southbound 

traffic. These structures are about 800 ft long and 34 ft wide 

and have spans of 37 ft. As was typical for structures at this 

time, they were built of a reinforced concrete T-beam construc:tion supported on pile bents. There were three expansion joints in the deck of each structure, effectively dividing 

the length of each into four segments. Seismic retrofitting, 

completed in 1984, consisted of the addition of cable restrainers at each expansion joint. 

These structures were supported by 22 pile bents along their 

length and by monolithic diaphragm abutments at the ends. 

Each bent consisted of four driven piles, approximately 80 ft 

long, which were driven to full length. Each pile was then 

extended by reinforced concrete columns to the underside of 

the superstructure into transverse cap beams. The pile extensions were lightly confined with wire. 

~>">~l<k Old shoreline 

- Freeways 1 KILOMETER 

-- City strreets and roads 

1 MILE 

Figure 5.-Location of the freeway viaducts in San Francisco. All 

but the Alemany Viaduct were damaged in the Loma Prieta 

earthquake. 
THE RESPONSE OF THE STATE OF CALIFORNIA TO THE LOMA PRIETA EARTHQUAKE D69 

During the earthquake, extremely strong shaking led to the 

collapse of the center two segments of each structure. Pile 

extension columns within these segments suffered severe 

cracking, buckling of longitudinal reinforcing, and fracture 

of the lateral confining reinforcement. Most of the columns 

sheared off at the interface with the underside of the transverse cap beams, immediately beneath the road deck. Seven 

spans of the northbound structure collapsed and dropped approximately 5 ft onto the damaged pile extension columns. 

Ten spans of the southbound structure collapsed and dropped 

8 to 10 ft to the ground surface. A few pile extension columns, sheared at the transverse cap beams, displaced and 

punched through the deck slab as the structure fell to the 

ground. Although the collapse was generally in the downward direction, the southbound structure displaced approximately 2 ft to the side. Apparently, some piles also failed below the ground surface. Soil displacements at the ground 

surface around the piles in several directions reached a maximum of 18 in at several piles. The approach fills settled approximately 3 in. 

The Stmve Slough Bridge showed little evidence of significant seismic forces reaching the superstructure above the 

abutments. There was no indication of horizontal movement 

at the abutments or of hammering at the expansion joints. 

Despite the significant displacements experienced by the road 

deck from the failure of the supporting piles, the cable restrainers performed well and held the deck together during 

these displacements. 

The primary cause of collapse is attributed to a lack of adequate concrete confinement and shear reinforcing at the top 

of the columns. Current practice and standards would require 

ductile detailing of these members, which would have led to 

substantially better seismic performance. 

IMPACTS ON CROSS-BAY TRANSPORTATION 

San Francisco Bay stretches about 65 mi from Alviso in 

the south to its northern boundary at the Richmond-San Rafael 

bridge. The stretch of water beyond this bridge is San Pablo 

Bay, ending at the Carquinez Bridge near Vallejo. Besides 

the Richmond-San Rafael Bridge, San Francisco Bay is 

crossed by three other bridges: the San Francisco-Oakland 

Bay Bridge, the San Mateo Bridge, and the Dumbarton Bridge 

(see figure 1). The Bay exits to the Pacific Ocean under a 

fifth bridge, the Golden Gate Bridge. In addition, the Bay is 

traversed by the Bay Area Rapid Transit (BART) trans-Bay 

tube between Oakland and San Francisco (fig. 1). The 

Carquinez Bridge crosses San Pablo Bay, and the Antioch 

and Benicia-Martinez Bridges cross the Sacramento River, 

which empties into San Pablo Bay to the east of the Carquenez 

Bridge. These Sacramento crossings provide alternative routes 

across to the north side of San Pablo Bay. 

The importance of integrating the Bay Area by bridging 

the water barrier between San Francisco and its neighbors 

was recognized early in the century. In 19 12 the engineer John 

Freeman predicted that the population of the Bay counties 

would reach 2 million within 40 years, and that towards the 

end of the century a population of 3 million might be reached, 

depending upon "the wisdom and vigor with which San 

Franciscans seize their opportunity" (Scott 1985). By 1980 

the San Francisco Bay counties had a population of 4.29 million, and their population is expected to increase to 5.24 million by the year 2005 (Diridon, 1988.) 

The San Francisco Bay crossings form a crucial part of the 

entire Bay Area transportation network. In the Bay Area counties, about 20 percent of the workers are employed outside 

their county of residence. It is estimated that this percentage 

will grow to almost 25 percent by the year 2005. At the same 

time, automobile ownership in the area is expected to rise 

from 3.3 million autos in 1990 to 5.1 million in the year 2005 

(Diridon, 1988). Hence the Bay Area highway network will 

continue to be crucial to the economy, but its maintenance as 

a swift and convenient means of travel will become increasingly difficult. 

Before the Loma Prieta earthquake, the five San Francisco 

Bay bridges together carried an average of 517,000 vehicles 

per weekday, and an average of 108,000 passengers rode on 

the BART trans-Bay tube and the ferries per weekday. The 

distribution of this traffic flow before and after the quake are 

given in table 1. Two facts stand out from these figures: the 

importance of the Oakland-San Francisco link; and the volume of traffic normally borne by the San Francisco-Oakland 

Bay Bridge (approximately equal to the combined traffic carried by all four other bridges). For automobile traffic, the 

Golden Gate and Bay Bridges are essentially non-redundant 

systems; alternative routes via the other bridges are extremely 

time consuming. In contrast to freeways, which are typically 

superimposed over an existing (if inadequate) road pattern, 

which is still available if a section of freeway is closed, the 

cross-Bay bridges have no satisfactory alternative. 

When the Loma Prieta earthquake damaged the Bay Bridge, 

causing immediate closure of the most widely used crossBay route for an indeterminate period, Bay Area traffic patterns were forced to change. Although there is an apparent 

change in cross-Bay total traffic, this is mostly a result of the 

fact that BART and the ferries count individual fares while 

the bridges count vehicles. 

The critical role played by the BART trans-Bay tube in 

cross-Bay transportation is clear from the figures in table 1, 

as is the fact that the South Bay bridges (San Mateo and 

Dumbarton) accommodated much of the redistribution of 

vehicular traffic. While ferry service more than tripled, from 

6,250 to 21,057 passengers, the number of people carried was 

still well below that of automobiles and the BART system. 

Total vehicles over the available bridges dropped from 5 17,370 

to 407,080 during the closure period. Many people apparently used BART or simply curtailed their travel. The effect 

of this pattern was noticeable in San Francisco; for example, 

many restaurants in the city had markedly fewer customers 

during this period. 
RECOVERY, MITIGATION, AND RECONSTRUCTION 

Table 1.-Volume of traffic using transportation links across Sun Francisco Bay before and 

after the Lorna Prieta earth!quake 

Transportation link Daily use (,weekday, Change 

both wavs) 

Before After Number Difference 

Earthquake Earthquake 

Counted by vehicles 

Richmond-San Rafael Bridge 44,000 79,173 +35,173 +79.9% 

Golden Gate Bridge 123,754 150,927 +27,173 +2 1.9% 

San Francisco-Oakland-Bay Bridge 243,116 0 -243,116 -100.0% 

San Mateo Bridge 65,000 109,79 1 +44,79 1 +68.9% 

Dumbarton Bridge 41,500 67,189 +25,689 +61.9% 

Total 5 17,370 407,080 -1 10,290 -21.3% 

Counted by passengers 

Bay Area Rapid Transit (BART) 102,152 226,876 +124,724 +122.1% 

tube 

All ferries 6,250 21,057 +14,807 +236.9% 

Total 108,402 247,933 l39,53 1 +128.7% 

That the economic and personal losses from the Bay Bridge 

closure were considerable is not in doubt, although much 

detailed study would be necessary to define them fully. If the 

Bay Bridge had not reopened within a month-a much shorter 

time interval than initially projected immediately after the 

collapse-the operational and economic consequences could 

have been much more severe. The equipment and maintenance facilities of BART, for example, were severely strained, 

and the post-earthquake increase in BART ridership could 

not have been sustained indefinitely. If the BART trans-Bay 

tube or the Golden Gate Bridge had simultaneously been 

closed for a comparable time, the economic and social consequences could have been dramatic. 

The closure of the Bay Bridge, though fortunately short, 

gave some indication of the disruption that could be caused 

by the long-term loss of one of the essential cross-Bay links. 

The Loma Prieta experience can be seen as a "live" exercise 

demonstrating the short-term closure of a single cross-Bay 

link. A previous accident-the fire in the trans-Bay tube in 

April 1979-resulted in closure of the tube for two and onehalf months. That experience also showed that failure of a 

single trans-Bay crossing can be accommodated, with some 

loss of convenience. 

The societal consequences from earthquake damage to the 

Bay Area highway system were considered in two earthquake 

planning scenarios developed and published by the California Division of Mines and Geology for the Office of Emergency Services. The first sketched the possible effects of a 

magnitude 8.3 earthquake on the San Andreas Fault (Davis 

and others, 1982). The second considered the effects of a 

magnitude 7.5 earthquake on the Hayward Fault (Steinbrugge 

and others, 1987). These studies considered what might happen if the scenario earthquakes occurred, and had the primary objective of making emergency response and recovery 

authorities aware of the types of situations that they might 

have to face. While they were carefully prepared and appropriate for planning purposes, they were not the result of engineering analyses of the expected performance of the physical 

structures they considered. 

The Loma Prieta earthquake demonstrated the vulnerability of Bay-crossing structures to even a relatively distant event. 

Future planning must recognize the likelihood and potential 

consequences of closer, more powerful events caused by earthquakes on the San Andreas and Hayward Faults. In particular, the possibility of the simultaneous failure of two or three 

Bay crossings would result in a situation for which there has 

been no precedent. Moreover, even if additional retrofits are 

implemented for the Bay Bridge and if the trans-Bay tube 

and the Golden Gate Bridge are deemed safe, the possibility 

of post-earthquake closure is always present. No engineering 

measures can guarantee a damage-free response of these structures to earthquake shaking. 
THE RESPONSE OF THE STATE OF CALIFORNIA TO THE LOMA PRIETA EARTHQUAKE D7 1 

The Bay crossings represent one component, though perhaps that with the least redundancy, of the Bay Area highway 

transportation system. This, in turn, forms part of a Statewide, indeed national, system-rail, air, ship-that is critical 

for the economic transportation of people, materials, and products. The transportation network itself forms one subsystem 

of the entire urban and regional structure of the State. In preparing for future earthquakes, it is necessary to identify and 

strengthen the weak links in these systems. 

Only aggressive programs of identification and strengthening can prevent the possibility of perhaps scores of tragic 

collapses similar to the collapse of the Cypress Viaduct in the 

event of a future, closer earthquake of longer shaking duration. In addition, the economic and administrative effects of 

such a quake could be deep and long-enduring, perhaps even 

threatening the viability of California as an attractive environment in which to live and work. 

FINDINGS AND RECOMMENDATIONS OF THE 

BOARD OF INQUIRY 

Central to the Board of Inquiry's process was the determination of what actually occurred during the earthquake and 

why. These findings formed the basis for the recommendations made by the Board. A large volume of information was 

considered, part provided through public presentations to the 

Board, part through study of documents and files. The 52 

findings of the Board were organized under the following 

general headings: 

1. Findings on seismology and ground motion 

2. General findings on transportation structures 

3. Findings on Caltrans seismic design practices 

4. Findings on the Bay Bridge failure 

5. Findings on the Cypress Viaduct collapse 

6. Findings on San Francisco freeway viaducts 

7. Findings on the Caltrans retrofit program 

8. Findings for other types of structures 

The full report of the Board (Housner and others, 1990) 

presents the specific findings, the rationale for each finding, 

and technical information on which each was based (see also 

Housner and Thiel, 1990). 

On the basis of these findings, the Board of Inquiry identified three essential challenges that must be met by the citizens of California, if they expect a future adequately safe from 

earthquakes: 

Ensure that earthquake risks posed by new construction 

are acceptable. 

Identify and correct unacceptable seismic safety conditions in existing structures. 

Develop and implement actions that foster the rapid, 

effective, and economic response to and recovery from 

damaging earthquakes. 

These challenges concern the problems not only of bridges, 

whose failure prompted the Board's formation, but also of all 

other constructed facilities upon which our modern economy 

and well-being depend. Although the Board could have limited its recommended actions to those it believed necessary 

to correct problems with State-owned bridges, to do so would 

have been to abdicate a fundamental responsibility of government-to provide for the public safety. The Board interpreted its Charter in a broad sense and made recommendations that are directed both at seismic issues for bridges and 

at some of the larger issues of seismic safety facing the State. 

The Board made the following eight recommendations for 

implementation (Housner and others, 1990, p 76-87). 

FOR ACTION BY THE GOVERNOR 

1. Affirm the policy that seismic safety shall be a paramount 

concern in the design and construction of transportation 

structures. Specific goals of this policy shall be that all 

transportation structures be seismically safe and that important transportation structures maintain their function 

after earthquakes. 

2. Establish that earthquake safety is a priority for all public 

and private buildings and facilities within the State by 

taking the following actions: 

A. Propose legislation to ensure that every new facility 

in the State not otherwise subject to adequate seismic regulation and having the potential to cause substantial life loss during an earthquake be subject to 

compliance with adequate seismic safety standards 

for construction. 

B. Require that seismic safety be a paramount concern 

in the design and construction of all State-owned 

structures. Specific goals of this policy shall be that 

all State-owned structures be seismically safe and 

that important State-owned structures maintain their 

function after earthquakes. 

C. Initiate and fund a vigorous, comprehensive program 

of research to improve the capability in engineering 

and the physical and social sciences necessary to 

mitigate earthquake hazards and to implement the 

technology transfer and professional development 

necessary to hasten practical use of research results. 

3. Direct the Seismic Safety Commission to review and advise the Governor and Legislature periodically on State 

agencies' actions in response to the Recommendations 

of this Board of Inquiry. 

FOR ACTION BY THE DIRECTOR OF THE DEPARTMENT OF 

TRANSPORTATION 

4. Prepare a plan, including schedule and resource requirements, to meet the transportation seismic performance 

policy and goals established by the Governor. The plan 

shall include the timely seismic retrofitting of existing 

transportation structures. 
D72 RECOVERY, MITIGATION, AND R.ECONSTRUCTION 

5. Form a permanent Earthquake Advisory Board of external 

experts to advise Caltrans on seismic safety policies, standards, and technical practices. 

6. Ensure that Caltrans seismic design policies and construction practices meet the seismic safety policy and goals 

established by the Governor: 

A. Review and revise standards, performance criteria, 

specifications, and practices to ensure that they meet 

the seismic safety goal established by the Governor 

and apply them to the design of new structures and 

rehabilitation of existing transportation structures. 

These standards, criteria, and specifications are to 

be updated and periodically revised with the assistance of external technical expertise. 

B. Institute independent seismic safety reviews for important structures. 

C. Conduct a vigorous program of professional development in earthquake engineering disciplines at all levels of the organization. 

D. Fund a continuing program of basic and problem-focused research on earthquake engineering issues 

pertinent to Caltrans responsibilities. 

7. Take the following actions for specific structures: 

A. Continue to sponsor and utilize the Independent Review Committee's technical reviews of the engineering design and construction proposed for the shortterm repair and strengthening of the San Francisco 

freeway viaducts. 

B. Develop a long-term strategy and program for the seismic strengthening of existing substandard structures, 

including the San Francisco freeway viaducts, that 

considers their overall behavior, the dlegree of seismic risk, and the importance of the structure to the 

transportation system and community. 

C. Perform comprehensive earthquake vulnerability 

analyses and evaluation of important transportation 

structures throughout the State, including bridges, 

viaducts, and interchanges, using state-of-the-art 

methods in earthquake engineering. 

D. Implement a comprehensive program of seismic instrumentation to provide measurements of the excitation and response of transportation structures during earthquakes. 

FOR ACTION BY TRANSPORTATION AGENCIES AND 

DISTRICTS 

8. Agencies and independent districts that are responsible for 

transportation systems-rail systems, highway structures, 

airports, ports and harbors-should: 

A. Adopt the same seismic policy and goals established 

by the Governor for State transportation structures 

and implement seismic practices to meet them. 

B. Perform comprehensive earthquake vulnerability 

analyses and evaluations of important transportation 

structures-for example, the BART trans-Bay tube 

and Golden Gate Bridge-using state-of-the-art 

methods in earthquake engineering, and install seismic instrumentation. 

(2. Institute independent seismic safety reviews for important structures. 

11. Conduct a vigorous program of professional development in earthquake engineering disciplines at all levels of their organizations. 

GOVERNOR'S QUESTIONS 

The Governor directed the Board of Inquiry to study and 

reach conclusions on five specific issues arising from the Loma 

Prieta earthquake (Deukmejian, 1989): 

1. To determine why the Cypress Viaduct of Interstate 880 

and the Bay Bridge span failed in the earthquake. 

2. To determine whether these failures were or could have 

been foreseen. 

3. To advise on how to accurately predict possible future bridge 

and structure failures. 

4. To determine if the schedule for and manner of retrofitting 

these structures properly used the seismic and structural 

information that has been developed following other 

earthquakes in California. 

5. To make recommendations as to whether the State should 

modify the existing construction or retrofit programs for 

freeway structures and bridges in light of new information gained from this earthquake. 

To this group of directives the Board itself added the question: 

6. Are California's freeways safe in earthquakes? 

Summary responses to these six issues, recast as questions, 

are given below. Background information and more detailed 

discu~ssion of these responses are to be found in the Board's 

Report (Housner and others, 1990). 

1. WHY DID THE CYPRESS VIADUCT OF INTERSTATE 880 AND 

THE BAY BRIDGE SPAN FAIL IN THE EARTHQUAKE? 

The Cypress Viaduct and the Bay Bridge appear to have 

had no design or construction deficiencies, as measured by 

bridge design practices in effect at the time they were built, 

nor is there evidence of subsequent maintenance deficiencies 

that could have contributed to their failure. However, the practice of earthquake engineering has improved substantially 

since the periods during which the Cypress Viaduct (1950's) 

and San Francisco-Oakland Bay Bridge (1930's) were designe;d and constructed. 

2. WERE THESE FAILURES FORESEEN OR COULD THEY 

HAVE BEEN FORESEEN? 

No evidence was presented to the Board suggesting that 

Caltrans was specifically aware of the earthquake hazards that 
THE RESPONSE OF THE STATE OF CALIFORNIA TO THE LOMA PRIETA EARTHQUAKE D73 

caused the failures of the Cypress Viaduct or the San Francisco-Oakland Bay Bridge. Although there had been some 

seismic strengthening of both structures by the installation of 

cable restrainers, there is no evidence that Caltrans had identified either structure as being especially vulnerable in earthquakes. 

The issue of whether these failures could have been foreseen in the Loma Prieta earthquake is a difficult one because 

of the uncertainties and lack of previous studies. The fiscal 

environment in the preceding two decades seems to have inhibited Caltrans from giving necessary attention to seismic 

problems. Many items, ranging from research on earthquake 

engineering to seismic retrofitting, were given low priorities 

because of budget constraints. 

The Board of Inquiry concluded that had an engineering 

seismic assessment of the Cypress Viaduct been performed 

before the earthquake, but after 197 1, by a professional engineering organization in a manner consistent with the care and 

expertise usually exercised in evaluating such important structures, it would have concluded that a collapse could be expected during a nearby major earthquake on the San Andreas 

Fault or Hayward Fault. Damage, but not extensive collapse, 

would have been expected for an earthquake similar to the 

Loma Prieta earthquake in magnitude and location. Collapse 

would have been anticipated for the intensity of ground motion actually observed in the Loma Prieta earthquake; however, the extent of the collapse that actually occurred would 

probably not have been anticipated. 

The Cypress Viaduct was a nonductile concrete structure. 

It has been common knowledge within the structural engineering community since the 1960's that nonductile reinforced 

concrete structures are particularly vulnerable in earthquakes. 

Most Caltrans concrete bridges constructed before 197 1 use 

nonductile details of reinforcing placement. Caltrans instituted design changes in 1971, following that year's San 

Fernando earthquake, that required new construction to utilize ductile details. However, for the Cypress Viaduct retrofit 

of 1977 a prior decision in the retrofit program dictated that 

the limited available funds should be used to install longitudinal restraints at the transverse expansion joints in the boxgirder spans. This was done to prevent failures of the type 

experienced in the San Fernando earthquake. Unfortunately, 

no detailed comprehensive analysis of the entire structuresoil system, to determine if other weaknesses existed, was 

made before the failure of the Viaduct on October 17, 1989. 

Had such an analysis been made, the Board believes the failure would have been predicted. 

The Bay Bridge is a very large and complicated structure 

made of steel and concrete and has foundations extending to 

rock or stiff soils through very soft, water-saturated soils. The 

assessment of seismic performance and possible damage to 

such a complex structure requires an unusually thorough and 

detailed investigation. Had such a study been made, it probably would have identified the possibility of collapse of the 

link span in addition to other hazards. 

3. HOW MAY POSSIBLE FUTURE BRIDGE AND STRUCTURE 

FAILURES BE ACCURATELY PREDICTED? 

Predicting the possibility of failures is confined to determining whether the bridge or structure could fail when subjected to a given level of ground shaking. This requires, first, 

that the level of ground shaking be determined for the site 

and, second, that an engineering assessment of expected performance be made for this level of ground shaking. The ground 

shaking used in such a failure analysis should be determined 

from a probabilistic risk assessment for the site, with an acceptable (small, consistent with the structure's importance) 

probability of exceedance during the projected lifetime of the 

structure. 

Because there are more than 11,000 State-owned bridges 

and a comparable number of locally owned bridges, it is not 

expected that all of these can or should be assessed with such 

rigor. Design standards used by Caltrans after 197 1 were better than those used before, and it is reasonable to expect that 

the older structures pose a greater risk. Application of risk 

analysis procedures that consider the frequency of occurrence 

of different levels of ground motion and the characteristics of 

each structure (configuration, materials, foundations, soils, 

age, and condition) could reduce the inventory of older bridges 

to a manageable list of potentially hazardous structures. Locations with a potential for ground failure (such as liquefaction or lateral spreading) deserve special attention. 

4. DID THE SCHEDULE FOR AND MANNER OF 

RETROFITTING THESE STRUCTURES PROPERLY UTILIZE 

THE SEISMIC AND STRUCTURAL INFORMATION 

DEVELOPED FOLLOWING OTHER EARTHQUAKES IN 

CALIFORNIA? 

Several freeway bridges collapsed in the 197 1 San Fernando 

earthquake when decks were pulled off their supports at expansion joints. The decks fell, causing failure of the bridges. 

This happened even though no significant direct damage was 

necessarily done to the bridge elements themselves by the 

ground shaking. In response, Caltrans adopted a statewide 

"cable restrainer" seismic retrofit program to prevent such 

failures by tying each deck section to adjacent sections and 

abutments. It took 17 years and expenditures of $54 million 

to complete this program. The Board concluded that this 

program significantly increased the seismic resistance of many 

structures, and its only major criticism was that 17 years was 

too long for completion of such an important program. 

During this post- 197 1 Caltrans retrofit program, the Cypress Viaduct and the San Francisco-Oakland Bay Bridge had 

been fitted with cable restrainers to limit the relative motion 

between adjacent decks at expansion joints. No special seismic analyses, however, were made of these structures. Following the 197 1 earthquake, seismic design procedures for 

new structures were modified to include ductile detailing for 

concrete elements, but no special efforts were made to retrofit existing nonductile concrete bridge elements. 
D74 RECOVERY, MITIGATION, AND RECONSTRUCTION 

The near collapse in the 1987 Whittier Narrows earthquake 

of the overpass at the intersection of highways 1-5 and 1-605 

emphasized the need for strengthening nonductile concrete 

bridge columns. An ongoing Caltrans research project was 

accelerated, and an inventory was made of single-column 

bridges having high hazard potential . The Cypress Viaduct, 

being a multiple column bridge, was not given high priority 

for attention. 

Early in the post-1971 retrofit program, Caltrans considered the performance of individual elements (restraining 

motion at expansion joints). Caltrans did not consider the response of the whole structure or the soil/structure system. 

This focus on elements, in hindsight, may have inhibited the 

identification of problems in overall seismic behavior such 

as those uncovered in the failure of the Cypress Viaduct and 

the Bay Bridge. 

The repair of the Bay Bridge appears to be appropriate for 

the short term. However, the fact that damage to this bridge 

during the Loma Prieta earthquake was only slight and has 

been completely repaired does not mean that the bridge may 

now be assumed to be adequately resistant to earthquake damage. The expected performance of the Bay Bridge during 

major earthquake loadings should be assessed by comprehensive state-of-the-art methods in earthquake engineering 

analysis. The results of this analysis should be used to determine what seismic upgrading is required to ensure adequate 

performance. 

The San Francisco freeway viaducts are substantially comparable to the Cypress Viaduct in their design and construction. These viaducts can be expected to suffer severe damage 

and possibly collapse if subjected to more intense or longer 

duration ground motions than those experienced in the Loma 

Prieta earthquake. The installation of cable restraints during 

the Caltrans seismic retrofit program appears to have improved 

their behavior, possibly saving some spans from collapse in 

1989 by limiting the relative displacements of the decks at 

the expansion joints. 

The repair of some of the San Francisco Freeway Viaducts 

was begun in 1990. The retrofitting is expected to strengthen 

the columns substantially, but the precise degree of improvement in seismic resistance of the structures requires detailed 

studies and analyses, which were not completed by the Board. 

The Board of Inquiry was unable to evaluate the specific details of the retrofit designs and programs for the individual 

viaducts. It considers this retrofit to be only a short-term approach to their repair. Substantially more engineering analysis and evaluation will be required to determine if additional 

seismic retrofitting may be necessary in order for the Bay 

Bridge and San Francisco freeway viaducts to be appropriately safe in the long-term. 

5. SHOULD THE STATE MODIFY THE EXISTING 

CONSTRUCTION OR RETROFIT PROGRAMS FOR FREEWAY 

STRUCTURES AND BRIDGES IN LIGHT OF NEW 

INFORMATION GAINED FROM THIS EARTHQUAKE? 

The answer to this question is an unequivocal yes. The Loma 

Prieta earthquake demonstrated that nonductile structures 

designed before 1971 can fail in a brittle manner with consequent collapse. It also showed that the intensity of ground 

shaking on soft soils can be greater than is anticipated by 

current seismic codes. This evidence requires modifications 

both to the retrofit program and to new design standards (see 

Housner and others, 1990.) In response, Caltrans appears to 

be vigorously modifying their technical approaches and standards for both. 

The existing Statewide Caltrans seismic retrofit program 

shoulld continue to consider the overall behavior of transportation structures and foundations and not focus principally 

on the behavior of structural elements instead of systems. The 

retrofit program should be enhanced by the assignment of 

greater personnel and budgetary resources so that it can be 

implemented and completed by the year 2000. 

Most of California's reinforced concrete bridges were designed and built before the 1970's, and many are deficient in 

their earthquake resistance. New knowledge in earthquake 

engineering for bridge design has been developed slowly 

through research, and there is always a lag in putting research 

results into practice. The quality, effectiveness, and economy 

of new construction and seismic upgrading will be enhanced 

substantially if a vigorous research program is undertaken on 

earthquake engineering, in contrast to the limited and occasiona~l efforts of the past. 

6. ARE CALIFORNIA'S FREEWAYS SAFE IN EARTHQUAKES? 

Most of California's freeway structures are adequately resistant to earthquakes, but some are not. Among the more 

than 11,000 structures in the State highway system, there are 

some that have the potential for severe damage and collapse 

in the event of the strongest expectable earthquake ground 

motions. These deficiencies warrant prompt, systematic correction; however, the Board of Inquiry did not deem that closure of any structure was warranted, based on the Board's 

understanding of past Caltrans seismic design and construction practices. The occasional earthquake risks to life and 

safety posed by highway structures in earthquakes are different from those continuously posed by traffic conditions. Earthquakes with ground motions large enough to pose a threat to 

a specific bridge have relatively low probability in any year. 

The Board thought that existing structures of high hazard 

can and should be corrected in a planned and accelerated program. With the implementation of the Board's recommendations, Caltrans could complete the identification of these stmctures and carry out the required seismic retrofitting. Then the 

State's freeway structures will be appropriately safe. 

STATE AGENCY ACTIONS 

Governor George Deukmejian issued Executive Order D86-90 in June 1990 in response to the Board of Inquiry's report (Housner and other, 1990). It provided the direction to 
THE RESPONSE OF THE STATE OF CALIFORNIA TO THE LOMA PRIETA EARTHQUAKE D75 

State agencies in how to implement many of the Board's recommendations. It established a State policy that seismic safety 

shall be given priority consideration in the design and construction of all State structures and in the allocation of resources for transportation construction projects. Priority consideration may be defined as assigning a specific factor-in 

this case, seismic safety-precedence when making a decision. The Executive Order also gave specific directives to State 

agencies. The Department of Transportation (Caltrans) was 

directed to: (1) prepare an action plan to ensure that all transportation structures maintained by the State are safe from 

collapse and vital transportation links maintain their function 

following an earthquake; (2) establish a formal process for 

obtaining external expert advice in seismic policies, standards, 

and technical practices and in the reviewing plans for retrofit 

or construction; (3) assign a high priority to the development 

of a program for research on earthquake engineering issues. 

The Department of General Services (DGS) was directed to 

prepare an action plan to ensure that all facilities maintained 

or operated by the State (other than those for which Caltrans 

is responsible) are safe from significant failure and that important structures maintain their function following an earthquake. The University of California (UC) and State University of California (CSU) systems were directed to prepare 

plans for increasing seismic safety of their facilities. All of 

these agencies were given only three months to submit the 

requested plans to the governor. Finally the California Seismic Safety Commission was directed to review the responses 

of the agencies and report to the Governor on the adequacy 

and status of their plans and actions. 

The Commission reviewed and analyzed the responses that 

each agency submitted to the Governor, using the criterion of 

priority consideration as given above as the benchmark in 

evaluating the adequacy and status of the efforts made. The 

Commission's staff discussed the problems identified during 

their review and analysis with representatives of the agencies. The Commission also conducted a public hearing on 

October 12, 1990, at which representatives of the four agencies were invited to discuss the concerns the Commission had 

expressed regarding their responses to the Executive Order. 

Agencies were asked to comment on the draft of the 

Commission's report, and their comments were considered 

when the final report was adopted by unanimous vote on 

November 8, 1990 (Seismic Safety Commission, 1990). 

The Seismic Safety Commission determined that an effective seismic safety program in response to the Governor's 

directives must include adequate consideration of the following (Seismic Safety Commission, 1990, p. 2.) : 

1. Policy Statement. A statement of policy that states 

goals, expectations, deadlines and that explains the 

ranking of seismic safety in the agency's responsibilities must be developed. 

2. Seismic Safety Program. A seismic safety program 

must be formulated that includes a plan and process 

to identify earthquake hazards to people and to organizations' functions, and recommendations to 

abate the unacceptable hazards or to prudently manage the risks that cannot be eliminated. 

3. Responsible Staff. A management-level agency official should be designated as having clear responsibility for meeting the goals in the policy statement, 

aided by an appropriately sized staff that has the 

administrative and technical knowledge and experience needed to carry out the program. 

4. Adequate Funds. Funds adequate to carry out the program or a plan to raise the needed funds must be 

identified. 

5. Accountability. A way to measure and report progress 

to the designated official, as well as to the Governor 

and the Legislature should be developed, as should 

a way to ensure technical performance in carrying 

out the program. 

The Commission found that, although great strides had been 

made during the previous few years to lessen the State's exposure to earthquake risks, there was still a long way to go. 

Table 2 summarizes the Commission's evaluation of the adequacy of each of the four agencies' responses to these five 

elements. Only Caltrans was evaluated as responding to the 

Executive Order with an adequate program. Although DGS 

made considerable progress in giving seismic safety priority 

consideration, it still had to find a solution to its fiscal resources problem. UC had begun to address seismic safety 

long before the Loma Prieta earthquake, but it did not reexamine or accelerate its existing program after the issuance of 

the Executive Order. Because of the lack of funding and the 

absence of a process of accountability, UC's program was 

evaluated as not adequate to meet immediate, existing seismic safety needs. Although CSU had responded to the Executive Order in good faith, it was far behind UC. Its response 

did not adequately address any of the five concerns essential 

for an effective seismic safety program. It seemed doubtful 

that either UC or CSU would be able to perform the planned 

seismic retrofits indicated in their responses; neither had the 

fiscal resources necessary to make seismic safety a priority 

consideration. 

The responsiveness of the agencies was in general inversely 

related to their experiences in the Loma Prieta earthquake. 

Caltrans, being heavily affected, moved quickly and forcefully to change its practices. It established a Seismic Advisory Board, reporting to the Director of Caltrans, to review 

its programs. Caltrans committed substantial additional resources to research and established a Research Program Committee to review research proposals and recommend future 

directions. It also established a standing Project Review Committee made up of outside experts in earthquake engineering 

to review individual projects. Combined with the commitment of substantial new resources to seismically retrofit existing hazardous bridges, these steps provided positive expectations of substantially improved seismic safety of highway 

structures in the near future. 
RECOVERY, MITIGATION, AND IRECONSTRUCTION 

Table 2.-Seismic Safety Commission's evaluation of the responses of four California 

State agencies to Executive Order D-86-90 

Department of Department university of California 

Element of response Transportation of General caLfornia State 

(Caltrans) Services University 

Policy Statement Excellent Good Excellent Poor 

Seismic Safety Program Very Good Good Good Very Poor 

Responsible Staff Excellent Good Good Fair 

Adequate Funds Good Poor Poor Very Poor 

Accountability Good Fair Fair Very Poor 

COMMON PROBLEMS IN AGENCY RESPONSE 

The Commission found that action on seismic safety programs in the State agencies named in the Executive Order 

was being delayed by problems common to all four agencies. 

Inadequate funding is the most serious of these problems, 

and the most difficult for the agencies to address internally. 

Competing priorities cannot be used as an excuse to compromise seismic safety in public buildings any more than they 

would be allowed to lessen fire code compliance in the private sector, The cooperation of the Governor and Legislature 

is essential to provide the financial support for timely elimination of seismic hazards in State buildings and structures. 

Other common problems and concerns identified by the 

Seismic Safety Commission (1 990) include: 

The capital outlay budgeting process is too slow and 

inflexible. 

Potential liability exposure for failing to correct known 

dangerous conditions may be significant. 

Independent peer review, which could optimize design 

and program solutions, prevent errors, and improve 

accountability, is generally lacking. 

Independent plan checking and construction inspection 

are needed for all projects. 

Proposed strengthening standards are not consistent 

among agencies. 

Seismic safety does not have statutory support as a priority. 

Recovery planning has not been considered, so there is 

high potential for lengthy disruption of operations. 

The Commission recognized seismic safety as a long-term 

endeavor that, to be achieved, must be institutionalized as a 

priority by governmental agencies (Seismic Safety Commission, 1990, p. 19-20): 

Even after today's problems are corrected, there must 

still be an ongoing effort and clearly defined accountability. California's government cannot let the lessons 

of the Loma Prieta earthquake fade as did those of the 

197 1 San Fernando Valley earthquake. Making certain 

that seismic safety programs are consistently pursued 

over the long term will require legislation establishing 

the official public policy that seismic safety is an important, priority factor in the governmental decision 

making and resource-allocation process. 

Agreeing with a recommendation of the Board of Inquiry, 

the Commission found that a meaningful oversight process is 

needed to ensure accountability for progress on seismic safety. 

The Commission's report drew attention to the Governor's 

executive authority to present, or to establish a mechanism to 

prepare, an annual report to the people of California on the 

progress that each State agency had made in seismic safety. 

Backed by the power and prestige of the Governor's Office, 

an annual report to Californians should motivate appointed 

agency heads to act quickly and effectively to mitigate seismic safety hazards. It could also encourage local governments 

to take appropriate action concerning their hazardous buildings and move on other earthquake planning items. 

Another aspect of accountability is introduced by the practice of "value engineering" as practiced by several State agencies. Value engineering is a process whereby outside experts 

in engineering and construction review project concepts and 

plans to eliminate problems and find ways of doing the work 

more cheaply. Value engineering experts rarely are experts in 

or even knowledgeable of seismic safety. They may assume 

that mere code compliance is sufficient to provide an adequate 

level of safety and recommend that structural systems or 

materials be changed to facilitate faster or less expensive construction. Although this is an important process to limit construction expenses to those absolutely necessary, economy 

must not be at the expense of seismic safety. Value engineering efforts that focus too heavily on reducing initial construction costs and deemphasize seismic safety through strict interpretation of the letter and not the intent of the seismic 

provisions of the building code can result in recommenda- 
THE RESPONSE OF THE STATE OF CALIFORNIA TO THE LOMA PRIETA EARTHQUAKE D77 

tions for construction techniques that leave buildings and 

structures far more vulnerable to earthquake damage than they 

should be. The value engineering review should always include the earthquake design engineer as part of the process 

and make every effort to assure a fair hearing to concepts 

introduced into the project to provide an adequate level of 

seismic safety and to maintain building functions after earthquakes. 

The Commission emphasized the critical problem of assuring funding for seismic safety (Seismic Safety Commission, 1990, p. 16): 

While the agencies targeted by the Executive Order 

each have some discretion in redirecting funds, most 

of their capital outlay funds have been approved by 

the Legislature and the Governor for specific purposes 

and cannot be readily diverted to other projects, no 

matter how worthy. The agency may propose, but it is 

the Governor and the Legislature who now must ensure that the wherewithal for seismic retrofitting, safe 

new structures, and ongoing emergency response and 

recovery plans is provided. General obligation bonds, 

revenue bonds, fees, and even tax increases must all 

be explored. Seismic safety is too important, and ignoring it will be too expensive, to drop because of lack 

of money. The existing level of earthquake risk is unacceptable. 

One impediment to priority funding of seismic safety is 

the State's capital outlay process. This process, which is 

project-based, requires departments to submit individual 

projects to prescriptive reviews at several different stages. Each 

review has the potential for creating delay and adding cost, 

increasing the risk that the project may be abandoned, suspended, or significantly changed. This project-based process 

tends to be slow and unnecessarily inflexible, particularly for 

State agencies with large ongoing capital outlay needs. Specific funding decisions have to be made so far in advance that 

there may be insufficient information on which to base those 

decisions. This is particularly true for seismic safety projects, 

in which the full scope of work to be done is seldom known 

until after the project is started. The result is the frequent need 

either to adjust the scale of the project to match the budget or 

to ask the Legislature for more money. Either path is time 

consuming, costly, and inefficient. Project-based budgeting 

is too slow to meet the need for increasing the seismic safety 

of State buildings. 

The Commission suggested that the program-based budgeting procedure used by Caltrans might be more appropriate for seismic-safety projects. Caltrans' procedures use careful planning, thorough programming, scheduling, and 

independent review of capital outlay needs to ensure accurate budgeting and yet provide flexibility within the budget 

allocated by the Legislature. While this approach may not be 

appropriate for agencies that have only periodic capital outlay needs, it could improve the effectiveness of seismic safety 

programs pursued by DGS, UC, and CSU. Like Caltrans, each 

of these agencies is confronted with the necessity of strengthening hundreds of structures. A flexible, program-based budget process is more conducive to meeting the complex needs 

of seismic retrofitting in a timely manner than a building-bybuilding (project-based) process. 

The Commission found that another important consideration for the State in providing funding and setting priorities 

to abate earthquake hazards is the potential for liability. Although fear of liability should not be the driving force, the 

State must recognize its potential exposure to liability if seismic safety remains just another competing need in resource 

allocation. The State didn't know that the Cypress Viaduct 

was a collapse hazard, but it is paying millions of dollars in 

damages to the victims of that collapse. This amount may be 

minuscule compared to the claims that might occur after the 

failure of State buildings that are known to be potential collapse hazards in an earthquake. It is also important to note 

that, although Chapter 2 of the Tort Claims Act (Sections 8 10- 

840.6 of the California Government Code) confers limited 

immunity upon the Regents of the University of California 

and the Trustees of the California State University system, 

under that law these individuals can still be held personally 

liable, along with the State of California, for failure to mitigate known dangerous conditions such as earthquake hazards (a precedent was the 1986 decision in Peterson vs. San 

Francisco Community College District). In determining 

whether an administrator, regent, or trustee is personally liable for an act or omission, the courts apply the "reasonable 

person" standard, which excuses honest errors in judgment 

but not the intentional ignoring of significant problems. 

Finally, the Commission recommended that the concept of 

seismic safety be extended and institutionalized beyond the 

four State agencies mentioned in Executive Order 86-90. It is 

perhaps particularly important for the Department of Corrections and the Department of Water Resources, whose buildings and construction programs are exempt from oversight 

by the Office of the State Architect, but all State agencies that 

build or maintain their own buildings should make seismic 

safety a priority. 

CONCLUSIONS 

The Loma Prieta earthquake was a clear and powerful warning to the people of California. Fortunately it was centered in 

a sparsely populated region outside a major urban area; had 

its center been within an urban area, the consequences would 

have been much greater. Although progress had been made 

during the previous two decades in reducing earthquake risks, 

much more could have been done. More aggressive efforts 

are needed to mitigate the consequences of earthquakes. 

An important lesson to be learned from this earthquake is 

that independent technical review is essential to achieve consistent excellence in civil engineering design and constmction. The design of structures entails the making of many decisions and technical compromises. A peer review should be 

conducted if the owner or client wants assurance that a project 

design will be of acceptable quality. 
D78 RECOVERY, MITIGATION, AND IRECONSTRUCTION 

The Loma Prieta earthquake also serves as a reminder that 

over the years improvements will continue to be made in seismic design. These result from research, the study of earthquake damage, and improvements in materials, among other 

things. As a consequence, structures that were designed within 

the understanding of a previous time, or even of the present, 

may not meet future standards of seismic safety. Such potentially hazardous structures should be identified and strengthened. It is especially important that this be done for major 

structures whose collapse would threaten many lives or would 

have a severe impact on the functioning of a community. 

There are lessons from this earthquake for those institutions, both public and private, that do not want to be confronted by problems like those faced by Caltrans after October 17, 1989. Technical excellence is not enough- Caltrans 

was evaluated by the Board of Inquiry as a management and 

engineering organization of great skill and dedication. The 

conditions that led to the observed unacceptable performance 

of bridges resulted from the lack of a specific seismic safety 

policy within the organization and from an insular attitude of 

looking almost solely within for technical content and guidance. In addition, there were critical gaps in the knowledge 

required to effectively mitigate earthquake hazards, and there 

were delays in incorporating such knowledge into practice. 

Before the Loma Prieta earthquake, Caltrans did not have 

a management-directed seismic safety performance goal that 

all its structures had to meet. The requirements for accommodating earthquakes were contained only in design documents for use by engineers on individual projects. It is common for construction projects to have many criteria and goals, 

not all of which can be met simultaneously within budgetary 

and time constraints. It is understandable that seismic requirements, when not specifically stated as part of policy, can become the subject of compromises as management makes allocations among competing uses for limited funds. During 

the decades before 1989, the pressure to relieve traffic congestion and the limitations on funds led to severe budgetary 

problems for Caltrans. The fact that it took 17 years to implement the modest-cost cable restrainer program after the 1971 

San Fernando earthquake suggests that seismic safety was 

not as pressing as other issues. Internal design guidance, especially without independent review, can not provide the same 

level of assurance of good seismic policies and practices as 

does a clear statement of minimum seismic safety goals for 

an organization. 

The Seismic Safety Commission reviewed the response to 

the Board of Inquiry's report and the Governor's Executive 

Order 86-90. On the basis of that review, th~e Commission 

recommended a number of actions that can and should be 

taken to improve the seismic safety in State-owned buildings 

and transportation structures (Seismic Safety Commission, 

1990, p. 22-24). These actions would cure deficiencies in the 

detailed action plans submitted by the agencies to the Governor, extend the same requirements to other agencies, and create a clear system of responsibility and accountability. Most 

of these actions could be effected through an executive order; 

others should be adopted independently by Caltrans, DGS, 

UC, and CSU to improve their programs; and a few should 

be enacted by the Legislature to ensure a firm and lasting 

corn~mitmento seismic safety policy and funding. The following is a brief summary of these recommendations: 

The Governor should issue an Executive Order that directs each State agency to designate a policy-level person to be accountable to the agency head for taking all 

reasonable steps to ensure the protection of employees 

and clients against the effects of earthquakes. The order should also: (1) direct agencies to adopt policies 

regarding the seismic safety of the buildings they use 

and to create and manage hazard abatement programs; 

(2) require independent peer review of all major 

projects; (3) require all agencies that own and operate 

large numbers of buildings, especially those exempt 

from Office of the State Architect (OSA) oversight, to 

prepare detailed action plans and to use the plan-checking services of OSA; (4) create an ad hoc Seismic Safety 

Construction Coordinating Council charged with resolving existing differences in seismic safety methodology 

and standards; (5) direct agencies to post warning signs 

on buildings determined to be hazardous in earthquakes 

and to retrofit or vacate those buildings as soon as possible, but certainly by the end of the century; and (6) 

require the Department of Finance to audit the agencies' compliance with the Executive Order. 

The Department of General Services, the University of 

California, and the California State University should 

provide for independent peer review of seismic safety 

methods, standards, and priorities and of project design criteria and concepts; the director of DGS and chancellor of CSU should adopt and implement an official 

seismic safety policy; and Caltrans should modify the 

make-up, reporting relationships, and responsibilities 

of its independent boards and resolve any disagreements 

with the Board of Inquiry's recommendations by discussing them with the Seismic Design Advisory Board. 

The Legislature should enact legislation making seismic safety a priority consideration in capital outlay programs; streamlining the capital outlay process; giving 

OSA authority over plan checking and construction inspection for all State-owned buildings; and placing a 

seismic safety bond measure on the next statewide ballot that would require the retrofit or abandonment of all 

State-owned buildings determined to be hazardous in 

earthquakes as soon as possible, but certainly no later 

than the end of the century. 

Although most of the Commission's recommendations for 

action were based on the Board of Inquiry's report and the 

Governor's Executive Order 86-90, some expanded the scope 

into other issues of seismic safety. The recommendation that 

hazardous buildings be posted with warning signs follows a 

recent trend of making the user of products and services aware 

of the hazard posed in their use. The Board had called for the 

retrofitting of hazardous bridges by a certain date, but the 
THE RESPONSE OF THE STATE OF CALIFORNIA TO THE LOMA PRIETA EARTHQUAKE D79 

Commission extended this recommendation to governmental buildings. This augmentation, if acted upon by the Governor, should go a long way toward achieving the goals proposed by the Board for all structures. 

Initial observation of the response of State agencies to the 

Loma Prieta earthquake is encouraging, but continued scrutiny is required to ensure that promises are fulfilled. Substantial efforts will be required to find the appropriate compromise between current seismic safety expenditures compared 

to other demands for scarce resources and the future consequences of these actions when an earthquake occurs. The 

Loma Prieta earthquake, like California's other recent earthquakes, had surprises that upon reflection should have been 

not only expected but anticipatable. The only thing lacking 

was the resolve and commitment to ask and answer the appropriate questions. 

Future earthquakes are inevitable-in California and elsewhere in the Nation. They represent a continuing danger to 

our population and economy. The consequences of severe 

earthquakes in urban areas will be extensive-too large to 

allow "business as usual" to continue. It is time to set priorities for seismic safety. Research and development must be 

supported to meet our needs for effective, economic strategies for earthquake hazard mitigation, and determined actions 

must be taken to reduce seismic risks. Earthquakes respect 

our actions, not our intentions. 

REFERENCES CITED 

Davis, J. F., Bennett, J. H., Borchardt, G. A., Kahle, J. E., Rice, S. J., 

and Silva, M. A,, 1982, Earthquake planning scenario for a 

magnitude 8.3 Earthquake on the San Andreas Fault the San 

Francisco Bay Area: California Department of Conservation, 

Division of Mines and Geology, Special Publication 61, 160 

PP. 

Deukmejian, George, 1989, Executive Order D-83-89: Executive 

Department, State of California, Sacramento, California, November, 1989. 

Diridon, Rod, 1988, Year 2005 Bay Area travel forecasts, technical 

summary: Oakland, California, Metropolitan Transportation 

Commission. 

Housner, George, and others, 1990, Competing against time-Report to Governor George Deukmejian from the Governor's 

Board of Inquiry on the 1989 Loma Prieta Earthquake: Sacramento, State of California, Office of Planning and Research. 

Housner, G.W., and Thiel, C.C., 1990, Competing against timeReport of the Governor's Board of Inquiry on the 1989 Loma 

Prieta Earthquake: Earthquake Spectra, v. 6, no. 4, p. 68 1-7 11. 

Nims, D. K., Miranda, Eduardo, Aiken, I. D., Whittaker, A. S., and 

Bertero, V. V., 1989, Collapse of the Cypress Street Viaduct as 

a result of the Loma Prieta Earthquake: Berkeley, University 

of California, Earthquake Engineering Research Center Report, 

85p. 

Scott, Mel, 1985, The San Francisco Bay Area-A metropolitan 

perspective (2nd ed.): Berkeley, University of California Press, 

363p. 

Seismic Safety Commission, 1990, Report to Governor George 

Deukmejian on Executive Order D-86-90: Sacramento, State 

of California, November 30, 1990, 25 p., 7 appendices. 

Steinbrugge, K. V., Bennett, J. H., Lagorio, H. J., Davis, J. F., 

Borchardt, Glenn, and Toppozada, T. R., 1987, Earthquake planning scenario for a magnitude 7.5 Earthquake on the Hayward 

Fault in the San Francisco Bay Area: California Department of 

Conservation, Division of Mines and Geology, Special Publication 78,243 p. 

Thiel, C.C., Housner, G.W., andTobin, L.T., 1991, State response to 

the Loma Prieta Earthquake- competing against time: Seismological Society of America Bulletin, v. 81, no.5, p. 2127- 

2142. 

APPENDIX-EXECUTIVE DEPARTMENT, 

STATE OF CALIFORNIA, EXECUTIVE 

ORDER D-86-90 

This executive order to improve State seismic safety was 

signed by the Governor on June 2, 1990, in response to the 

report and recommendations of the Board of Inquiry on the 

Loma Prieta Earthquake of 1989. 

Whereas, on October 17, 1989 a major earthquake occurred in 

Northern California, causing deaths, injuries, and widespread damage to transportation facilities and other structures; and 

Whereas, an independent Board of Inquiry was formed in November 1989 to investigate the reasons for the collapse of transportation structures and to recommend actions to reduce the danger of 

tragic structural failures in future earthquakes; and 

Whereas, the Board of Inquiry found that there is a high probability that one or more major earthquakes will strike heavily populated 

areas in Northern and Southern California in the future; and 

Whereas, California's state of earthquake readiness needs improvement to better protect the public safety and our economy from potentially serious impacts of future earthquakes; 

Now, therefore, I, George Deukmejian, Governor of the State of 

California, by virtue of the power and authority vested in me by the 

Constitution and Statues of the State of California, do hereby issue 

this Order, to become effective immediately: 

1. It is the policy of the State of California that seismic safety shall 

be given priority consideration in the allocation of resources 

for transportation construction projects, and in the design and 

construction of all state structures, including transportation 

structures and public buildings. 

2. The Director of the Department of Transportation shall prepare a 

detailed action plan to ensure that all transportation structures 

maintained by the State are safe from collapse in the event of 

an earthquake and that vital transportation links are designed 

to maintain their function following an earthquake. The plan 

should include a priority listing of transportation structures 

which will be scheduled for seismic retrofit. The Director shall 

transmit this action plan to the Governor by August 3 1, 1990. 

3. The Director of the Department of Transportation shall establish 

a formal process whereby the Department seeks and obtains 

the advise of external experts in establishing seismic safety 

policies, standards, and technical practices; and for seismic 

safety reviews of plans for construction or retrofit of complex 

structures. The Director shall transmit a summary of this process to the Governor by August 3 1, 1990. 

4. The Director of the Department of Transportation shall assign a 

high priority to development of a program of basic and prob- 
D80 RECOVERY, MITIGATION, AND RECONSTRUCTION 

lem-focused research on earthquake engineering issues, to include comprehensive earthquake vulnerability evaluations of 

important transportation structures and a program for placing 

seismic activity monitoring instruments on transportation structures. The Director shall transmit a description of the research 

program to the Governor by August 3 1, 1990. 

5. Local transportation agencies and districts are encouraged to review the findings and recommendations of the Board of Inquiry on the 1989 Loma Prieta Earthquake and to adopt policies, goals, and actions similar to those proposed for Caltrans. 

6. The Director of the Department of General Services shall prepare 

a detailed action plan to ensure that all facilities maintained or 

operated by the State are safe from significant failure in the 

event of an earthquake and that important structures are designed to maintain their function following an earthquake. The 

plan should include a priority listing of facilities which will be 

scheduled for seismic retrofit. The plan shall further propose 

measures by which state agencies constructing new facilities 

or retrofitting existing facilities would: 

a. be governed by the provisions of a generally accepted earthquake resistant code for new construction; 

b. secure structural safety review and approval from the Office 

of the State Architect; 

c. seek independent review of structural and engineering plans 

and details for those projects which employ new or unique 

construction technologies; and 

d. have independent inspections of construction to insure compliance with plans and specifications. 

The Director shall transmit the plan to the Governor by August 

31, 1990. 

7. The Department of General Services shall, when negotiating leases 

of facilities for use by state employees or the public, consider 

the seismic condition of the facilities and shall initiate leases 

only for those facilities which demonstrate adequate seismic safety. 

8. The Seismic Safety Commission shall review state agencies' acdons in response to this executive order and the recommendadons of the final report of the Board of Inquiry and provide a 

report to the Governor on the adequacy and status of actions 

taken by December 1, 1990. 

9. The University of California and the California State University 

shall give priority consideration to seismic safety in the allocation of resources available for construction projects. The University of California and the California State University shall 

prepare and transmit to the Governor by August 31, 1990 a 

description of their plans to increase seismic safety at facilities 

which they maintain or operate. 
THE LOMA PRIETA, CALIFORNIA, EARTHQUAKE OF OCTOBER 17,1989: 

SOCIETAL RESPONSE 

RECOVERY, MITIGATION, AND RECONSTRUCTION 

EARTH SCIENCE, EARTHQUAKE RESPONSE, AND HAZARD MITIGATION: 

LESSONS FROM THE LOMA PRIETA EARTHQUAKE 

By William M. Brown I11 and Carl E. Mortensen 

CONTENTS 

Abstract.. ....................................................................... Introduction.. ................................................................. The role of earth science in earthquake response .......... 

Earth science response to the 

Loma Prieta earthquake ............................................ Planning for earthquake response ................................. The National Earthquake Hazards Reduction 

Program and the Plan for Federal Response 

to a Catastrophic Earthquake ............................... RESPONSE-89 exercise ........................................... USGS actions and interaction with the 

earth-science community following the 

Loma Prieta earthquake ....................................... 

The StateFederal Hazard Mitigation Survey Team.. .... Communications.. .......................................................... Conclusions and recommendations.. ............................. Acknowledgments.. ....................................................... References cited ............................................................ 

Page 

D8 1 

81 

82 

8 3 

83 

83 

8 5 

86 

87 

88 

88 

89 

89 

ABSTRACT 

The Loma Prieta earthquake and its aftermath offered an 

opportunity to examine the interrelations between the earthscience research community and those agencies and institutions charged with managing hazard reduction activities, including long-term mitigation, preparedness, response, 

recovery, and reconstruction. We describe the actions undertaken by the U.S. Geological Survey (USGS) after that earthquake and examine them in the larger context of the earthscience community's response to catastrophic earthquakes. 

Federal legislation governing disaster response and earthquake 

hazard mitigation provides a basis for defining a role for that 

community. This role includes providing information, essential for informed decision-making at all levels, to policy makers, response and recovery officials, and the general public. 

We recommend that this role be formally recognized and facilitated through deliberate advance planning. We also recommend that the USGS participate in regularly scheduled 

earthquake response exercises; execute formal agreements and 

prearrangements with primary response agencies; participate 

on hazard mitigation teams to formulate mitigation recommendations; and develop disaster-resistant communications 

links to disseminate information to response officials. These 

and other actions will help ensure that response to catastrophic 

earthquakes is coherent and coordinated and is based on the 

best available scientific information. 

INTRODUCTION 

During the response to and recovery from the Loma Prieta 

earthquake, the earth-science community interacted with operating agencies in a variety of ways. These interactions warrant examination to determine how effective they were and 

whether organizational changes or additional arrangements 

could provide an improved response to future severe earthquakes. Historically, there has been little direct connection 

between emergency response planning and earth-science research conducted under the National Earthquake Hazard Reduction Program (NEHRP). Research was seen as purely a 

long-term endeavor whose results sometimes take years to 

be translated and applied to hazard reduction. Response and 

recovery were seen as immediate necessities to which earthscience researchers had little to contribute. As monitoring and 

assessment capabilities have improved, however, this situation has gradually changed. By using powerful techniques 

for evaluating hazards in near real-time, the earth-science 

community is now able to provide rapid solutions to urgent 

problems posed during response and recovery operations. 

This paper describes two avenues for the immediate translation and transfer of earth-science research results. The report of the joint StateFederal Hazard Mitigation Survey Team 

(HMST), which is mandated under Federal law in any declared disaster, and the Plan for Federal Response to a Catastrophic Earthquake (currently undergoing revision to encom- 
D82 RECOVERY, MITIGATION, AND RECOVERY 

pass all types of natural disasters) offer opportunities to affect long-term mitigation activities and response actions, respectively, through direct participation and through deliberate planning. We briefly summarize the role of earth science 

in earthquake response, illustrated by the investigations carried out in the wake of the Loma Prieta earthquake, in order 

to place into context the opportunities that are available to 

affect earthquake response and hazard-mitigation policy following any severe earthquake. 

This paper focuses on certain contributions to hazard mitigation by the earth-science community following a severe 

earthquake. The response of the engineering community is 

widely recognized and substantial, but a discussion of those 

activities is outside the scope of this paper and beyond the 

expertise of the authors. We review the coordinating role assumed by the U.S. Geological Survey (USGS) for earth-science investigations and activities in the aftermath of the Loma 

Prieta earthquake, recognizing that the Earthquake Engineering Research Institute (EERI) played a similar role in coordinating activities of the many agencies and entities contributing to engineering aspects of the Lorna Prieta response. 

THE ROLE OF EARTH SCIENCE 

IN EARTHQUAKE RESPONSE 

When a damaging earthquake occurs, the earth-science 

community has three principal obligations: (1) to gather and 

analyze basic data; (2) to provide hazard evaluations and advice to responding authorities; and (3) to provide information and advice to the general public. The activities undertaken to fulfill these objectives can be made more effective 

through preplanning and coordination with the operational 

response agencies. 

The data that must be gathered and analyzed by earth scientists in order to fulfill their role of providing advice and 

information, and to further the understanding of earthquake 

processes, include observations to achieve the following objectives. Some examples from the Loma Prieta earthquake 

are given. 

1. Determine source parameters, mechanism, and characteristics of the earthquake.-These data may help to determine whether the event is a main shock or perhaps a 

foreshock to another, possibly larger event. These data 

also may be used to place the earthquake in a time sequence of other earthquakes for the region and can aid in 

estimating the probabilities of future earthquakes (Working Group on California Earthquake Probabilities, 1990). 

2. Characterize the distribution and parameters of strong 

ground shaking.-Rapid processing of broadband strongmotion recordings from in-place arrays (Brady and Mork, 

1990) and aftershock recordings from portable instruments can provide valuable data to authorities concerned 

with reconstruction and zoning decisions, as in the Marina District of San Francisco (Holzer and others, 1990). 

3. Map the distribution of ground effects.-These data lead to 

estimates of ground displacements, shaking intensities, 

extent of landsliding, occurrence of liquefaction, and 

other effects of the earthquake (U.S. Geological Survey 

Staff, 1990). Such information is vital for response agencies to best deploy their resources to areas of need and to 

assess the possibilities of latent effects of the earthquake. 

This information is also essential to decisionmakers planning long-term recovery and reconstruction in order to 

mitigate effects of future earthquakes as required by law 

(see later section titled "Planning for earthquake response"). 

4. Map the extent of surface rupture, if any.-For both primary and secondary breaks, the length and width of the 

mpture are measured, as well as the vertical and horizontal offsets of the ground. This work defines the fault 

segment that has broken and has implications about which 

segments are likely to break in future events. It also helps 

i~n estimating how large a volume of the Earth's crust 

was affected by the movement and in gauging the poten- 

~ial limits of different levels of damage. 

5. Measure afterslip.-Afterslip is postseismic creep in the 

rupture zone that can increase stress on the margins of 

the zone. This activity has the potential to produce new 

ground rupture for several days to weeks following the 

main event and to cause movement on nearby fault zones. 

These data must be gathered promptly after an earthquake 

because (1) most of the indicators, such as ground cracks, are 

perishable and must be observed and measured before they 

are obliterated by grading, reconstruction, rainfall, or other 

processes and activities; (2) the data constitute the primary 

information for further mitigation of effects of future earthquakes, both specifically for repeated characteristic earthquakes on the same fault and for earthquakes in general; and 

(3) some of the data are prerequisite for the mandated warnings and advisories concerning aftershocks and other hazards that derive from analysis of the data. 

Warnings and advisories to authorities and to the public 

depend on rapid, preliminary analysis of the basic data collected. These advisories include estimates of aftershock probabilities and timing, landslide risk, risks of other continued 

or progressive ground-failure effects, especially those that can 

be induced by aftershocks, and projections of afterslip and 

the risks of earthquakes induced on adjacent fault segments. 

After the Loma Prieta earthquake, the USGS routinely issued advisories about aftershock activity and probabilities and 

cooperated extensively with the news media in relaying this 

information to the general public. No post-earthquake information is of greater interest to the general public than aftershock forecasts because of the concern and anxiety aftershocks 

cause. Aftershock information therefore needs to be realistic 

and accurate, but presented in a dispassionate, calming fashion so that people can fully understand what they will have to 

live with over the next several months to years. 

Earth scientists can help to determine the risks faced by 

rescuers and others working in or around particular damaged 
EARTH SCIENCE, EARTHQUAKE RESPONSE, AND HAZARD MITIGATION D83 

structures, such as partially collapsed buildings or bridges. 

They may also be asked for advice on the redevelopment of 

specific damaged areas, including the types of development 

feasible considering both short-term and long-term seismic 

hazards. Earth scientists may be called to testify before commissions and special hearings on such matters as why a particular facility failed or how effective particular codes were 

in ensuring safe development (see, for example, U.S. Congress, 1989). They may be asked to give information to insurance companies on matters such as the conditions of a failed 

site before an earthquake or the location of a site with respect 

to various mapped seismic hazards. 

Finally, information and advice to the general public is required in order to (1) satisfy the immediate, large, and continuing demand for explanations of what happened; (2) direct inquiries to the proper information source; and (3) counsel 

people about what is likely to happen next. Knowledge itself 

has a salutary effect and goes a long way toward minimizing 

irrational, counterproductive personal responses. People want 

knowledge to help them evaluate their own risks, and making the best information available encourages rational, productive responses by individuals regarding their particular 

circumstances. People need to be advised about whether to 

rebuild, to buy earthquake insurance, to return to work, to 

send their children back to school, and whom to contact for 

additional information. Many such questions are asked of earth 

scientists, and they should be prepared to answer them or 

refer people to specific sources of information. In addition, 

there is an obligation for earth scientists to make the public 

aware of earthquake hazard mitigation opportunities. 

EARTH-SCIENCE RESPONSE TO THE 

LOMA PRIETA EARTHQUAKE 

After the Loma Prieta earthquake struck, earth scientists 

and technicians from numerous institutions and agencies immediately undertook reconnaissance investigations of the effected areas, primarily by aircraft and automobile (Plafker 

and Galloway, 1989). The various reconnaissance teams had 

different objectives, which included determining the character and extent of surface faulting, mapping the distribution of 

ground failures caused by liquefaction and landslides, and 

estimating the distribution of shaking intensities from observations of damage and other factors. Post-earthquake investigations by groups within the USGS were coordinated, following prearranged plans based on experience gained in 

responding to other earthquakes worldwide; most USGS activities were under the general guidance of the Branch of 

Engineering Seismology and Geology (now part of the Earthquake Hazards Team). For the reconnaissance and investigation effort of the wider earth-science community however, 

there was little in the way of centralized coordination in the 

early stages, though this rapidly began to develop as a result 

of the common needs of investigators. 

Some post-earthquake investigations involved the execution of prearranged plans, but many contingencies had to be 

dealt with through ad hoc arrangements. One such unplanned 

aspect was volunteered efforts. Scientists and engineers who 

happened to be in the San Francisco Bay region on other business when the earthquake struck immediately came to offer 

assistance, and soon other people with experience and interests in earthquakes began to pour into the region from throughout the world. Many (perhaps most) of the earth scientists 

who joined the response in these ways contacted the USGS 

for the information they would need to embark upon their 

investigations. 

As the response developed, USGS activities were coordinated through meetings held every evening at the USGS 

Western Region Center in Men10 Park, California. Presided 

over by the Chief of the Branch of Engineering Seismology 

and Geology, these meetings were attended by scientists and 

technicians from the USGS, universities, and other agencies, 

plus representatives of the news media. The meetings served 

to consolidate the observations and data gathered during the 

day in an effort to form a coherent picture of the earthquake 

mechanism, processes, and effects; to identify critical gaps 

in information; and to coordinate plans for further efforts. At 

each meeting, the day's activities and findings were presented 

and discussed, and information was posted on maps or in other 

forms of data displays on the walls of a large room, where it 

remained for further inspection by all investigators. Open 

access and direct media attention to the accumulating results 

helped to focus the response on the most critical issues and 

areas. 

In the remainder of this paper we attempt to evaluate the 

successes and shortcomings of the earth-science response to 

the Loma Prieta earthquake and the interrelations of agencies, institutions, and individuals involved in the response. 

Studies conducted after the earthquake revealed that the next 

large San Francisco Bay area earthquake is probably not far 

in the future, and the lessons we learned in 1989 must be well 

considered in preparing us for that next event. 

PLANNING FOR EARTHQUAKE 

RESPONSE 

THE NATIONAL EARTHQUAKE HAZARDS 

REDUCTION PROGRAM AND THE PLAN FOR 

FEDERAL RESPONSE TO A CATASTROPHIC 

EARTHQUAKE 

The Plan for Federal Response to a Catastrophic Earthquake, hereafter referred to as the Plan (Federal Emergency 

Management Agency, 1986, 1987, 1989), was developed by 

the Federal Emergency Management Agency (FEMA), which 
D84 RECOVERY, MITIGATION, AND RECOVERY 

assumes the lead coordinating function for earthquake response by all participating Federal agencies. The Plan was 

authorized under the National Earthquake Hlazards Reduction Program (NEHRP), enacted by the Congress in 1977 and 

amended in 1990; authorities that accrue to various agencies 

under the Plan derive from the Robert T. Stafford Disaster 

Relief and Emergency Assistance Act, PL 93-288, as amended, 

hereafter referred to as the Stafford Act. In the terminology 

of disaster planning, "response" refers to actions taken to save 

or protect lives and property immediately after an earthquake 

or other disaster; "recovery" includes measures to satisfy vital human needs with interim measures that may last for several months; and "reconstruction" refers to efforts that may 

extend over many years to rebuild and renew public and private buildings, roads, utilities, and other facilities. The Plan 

covers only response. Federal recovery and reconstruction 

measures are covered under a variety of other legislation and 

programs. The Plan is currently undergoing revision to cover 

Federal response to all natural disasters. Some organizational 

details will be changed in the new draft, but the basic structure and concept of operations will remain the same. 

The Federal response to disasters is managed at the national level by the Catastrophic Disaster Response Group, 

headed by FEMA and comprising representatives of the various Federal disaster-response agencies. This group oversees 

the allocation of Federal resources in a disaster and responds 

to Congressional attention. In this paper, we concentrate on 

response at the regional level, where input from the earthscience community can have its greatest and most immediate 

impact. The regional structure for Federal response under the 

Plan at the time of the Loma Prieta earthquake is diagrammed 

in figure 1. The regional effort is directed by the Federal Coordinating Officer (FCO), a FEMA official, assisted by an 

Emergency Support Team (EST) comprising key aides and 

advisors. Included among the technical advisors is the Science Advisor. Since the Loma Prieta earthquake, the Science 

Advisor function has been placed within Emergency Support 

Function 5 (now called Information and Planning). 

Once the President declares a disaster in accordance with 

the Stafford Act, the Plan may be activated. Because the Loma 

Prieta earthquake was not considered "catastrophic" in the 

sense that local and State response resources were not completely overwhelmed, the Plan was not fully implemented. 

Under the partial implementation, however, the Federal response structure was staffed, missions were assigned, and 

funds were provided to various Emergency Support Function (ESF) agencies to carry out response activities. 

The Stafford Act has evolved over time, with the experience from past disasters being used to call for new specific 

and useful activities. Many of these activities rely on applications of scientific research. The Stafford Act specifies that 

the President ensure that all appropriate Federal agencies are 

prepared to issue warnings of disasters to State and local officials. This means that, where feasible, earthquake forecasts 

and predictions, including aftershock warnings and other advisories following earthquakes, are required by law. Such 

warnings are therefore not simply a freely offered public service:, but a duty of those agencies with the scientific capability to devise and issue them. The Stafford Act also requires 

that emergency support teams of Federal personnel come to 

the assistance of the President's appointed Federal Coordinating Officer (FCO). The Act mandates the presence of Federal earthquake specialists on the emergency support teams 

in the aftermath of an earthquake and hence offers a significan). opportunity for scientists to help direct the Federal resporase. 

The Stafford Act is unambiguous on the responsibility of 

certain agencies to issue warnings and advisories. However, 

care must be exercised in the entire warning procedure. The 

wording of warnings needs to follow specific formats concerning time, location, actions to be taken, and duration of 

the warning period. Response agencies and the general public will take official warnings as authority to act, and therefore careful consideration must be given to questions of liability and service to the community. Generally, issuing 

warnings requires significant preplanning, particularly in 

writing sample warning statements that can be rapidly modified to suit particular situations when real warnings need to 

be issued. The mechanisms for issuing warnings also need to 

be preplanned, particularly in determining who is to be contacted regarding the warning and how the warning is to be 

distributed through the media. Procedures for issuing natural-hazards warnings are discussed in a report by Gori and 

Hays (1987), and a case study is available in the Parkfield 

Prediction Experiment of the USGS (Bakun and others, 1987). 

The earth-science research community is not generally integrated into the Plan, except in a fairly circumscribed way, 

and their response to the Loma Prieta earthquake was mostly 

not formally preplanned, but generally ad hoc. This is not to 

say that the earth-science response in general, and that of the 

USGS in particular, was not effective. Rather, the valuable 

lessons of the Loma Prieta experience should form the basis 

for a deliberately planned response to future, more severe 

earthquakes that will heavily tax organizations, coordination 

measures, and material and personnel resources. A considerable body of experience in responding to disasters has evolved 

within the USGS as a result of previous responses to significan! earthquakes and volcanic eruptions. Substantial response 

efforts were mobilized after the Armenian earthquake of 1989 

(in <he former USSR) and the eruptions of Mt. St. Helens in 

1980 (U.S.A.) and Nevado de Ruiz in 1985 (Colombia). Planning in advance of such events serves to create a more efficient and effective response and to identify potential resource 

shortfalls. In order for such planning to take place, it is necessary to understand the basic elements of the Plan, its concepi, of operations, and how the resources and capabilities of 

the research community can best be integrated into the response operations and enhance their overall effectiveness. 
EARTH SCIENCE, EARTHQUAKE RESPONSE, AND HAZARD MITIGATION D85 

RESPONSE-89 EXERCISE titled RESPONSE-89, was held during August 9-11,1989, just 

two months before the Loma Prieta earthquake. Conducted 

To ensure effective implementation of emergency response jointly by FEMA and the Governor's Office of Emergency 

plans, these plans must be tested and refined through Services (OES) of the State of California, the exercise brought 

appropriate exercises. A major earthquake response exercise, together State and Federal agencies from throughout Califor- 

, Federal Coordinating Officer 

#' (FCO) Emergency 

Support Function 

(ESn: 

*Senior Officials 

of Primary and 

support staff and Support flgencies 

functional branches Emergency 

Support Team jlduisors: 

(EST) *Science 

*Legal 

*National 

security 

s4iRRQw 

*Public 

information 

*Congressional 

liaison 

Operations 

Construction 

Management 

Fire 

Fighting 

rb Mass Care 

Health & Med. 

Seruices 

Urban Search & 

Rescue -- - - 

Hazardous 

Materials 

ESF 11 JÃ‘ 

JÃ‘ Transportation 

- 

Communications 

Damage 

Information - 

Resources 

Support 

Figure 1 .-Functional organization of a regional Disaster Field Office (DFO) from the Plan for Federal Response to a Catastrophic Earthquake 

(at the time of the Loma Prieta earthquake). The various Emergency Support Functions (ESP's) are conducted by staff of the different 

Federal agencies involved in the response under the direction of the Federal Coordinating Officer (FCO). 
D86 RECOVERY, MITIGATION, AND RECOVERY 

nia in a simulated response to an earthquake scenario for 

the Hayward Fault Zone in the San Francisco Bay region. 

During the RESPONSE-89 exercise, the designated Science Advisor provided information on aftershocks to the Federal Coordinating Officer (FCO) and to the various Emergency Support Functions (ESF7s), particularly those concerned 

with the safety of unstable structures. The primary agency 

for one such ESF (ESF-3, Construction Management), the 

U.S. Army Corps of Engineers (USACOE), found aftershock 

probabilities computed by the method of Reasenberg and 

Jones (1989) to be useful in organizing their response activities during the exercise. 

Participation in the RESPONSE-89 exercise by the U.S. 

Geological Survey served to introduce key USGS personnel 

to the local FEMA Region IX organization and officials, 

greatly facilitating subsequent interactions during the actual 

response to the Loma Prieta earthquake. 

USGS ACTIONS AND INTERACTION WITH THE 

EARTH-SCIENCE COMMUNITY FOLLOWING 

THE LOMA PRIETA EARTHQUAKE 

For 8 days after the Loma Prieta earthquake, aftershock 

probabilities were calculated twice a day and widely disseminated to responding agencies and to the news media 

(Reasenberg, 1990). Later, the frequency of these aftershock 

forecasts gradually diminished. Initial distribution included 

the California OES, the USACOE, and FEMA. Other agencies were added to the list as they requested information. 

Another USGS response action following the Loma Prieta 

earthquake was to establish a direct radio link to the site of 

rescue operations at the collapsed Cypress Street freeway 

structure (Interstate Highway 880 in Oakland). This link allowed the USGS to give rescue workers about 27 seconds of 

advance warning before the beginning of ground shaking from 

larger aftershocks occurring in the epicentral area (Bakun and 

others, 1994). Such warnings could also be useful in future 

rescue operations in partially collapsed, unreinforced masonry 

buildings or in other badly damaged structures at sufficient 

distance from the epicenter. This is an example of a new capability that could be formalized in the plans of ESF-9, Urban Search and Rescue. 

In such ways, the USGS and other research institutions may 

contribute directly to the response operations of a particular 

ESF. The Science Advisor to the FCO, however, must avoid 

becoming engrossed in ESF staff functions in order to fulfill 

the role of observing response operations overall and advising the FCO of opportunities for scientific capabilities to be 

applied to important problems. The Science Advisor must 

advise the FCO of the risk of progressive ground-failure processes and the expectation of damaging aftershocks. During 

the response to the Loma Prieta earthquake, the Science Advisor found it useful to attend the nightly briefings by field 

personnel at the USGS and to interpret, condense, and report 

the important facts from these meetings to the FCO and to 

ESP 3 (Construction Management). 

A valuable contribution that could be made by the USGS 

after a damaging earthquake would be to provide response 

agencies with a quick estimate of likely damage intensity and 

distribution. Such estimates could be based on the magnitude 

and location of the earthquake and on the local geological 

factors. This contribution was not available following the 

Lorna Prieta earthquake, but the analytical techniques that 

could be applied to produce such estimates were verified in 

that earthquake (Borcherdt and others, 1991). Possible application of these techniques is suggested by the following recenk experiences. Both the RESPONSE-89 exercise and the 

Lorna Prieta earthquake demonstrated that, particularly for 

critical life-saving tasks, the method of allocating resources 

by waiting for resource requests to arrive from local responders was unworkable. The very areas most in need may be 

least able to formulate and communicate requests for help. In 

more severe earthquakes in the future, it is expected that local government itself will be a victim-overtaxed before it 

can respond. Response planners therefore have determined 

to implement what is referred to as a "push system," under 

which critical life-saving functions are preassigned 

("pretasked") to respond to the event without waiting for formal tasking or mission assignment (Federal Emergency Management Agency, 1990, p. 44). Indeed, some of the most effective Federal response efforts after the Loma Prieta 

earthquake resulted from ad hoc "push" efforts by units acting without prior formal authorization. The push system offers an opportunity for the USGS to contribute immediately 

by providing real-time notifications of earthquake facts and 

predicted earthquake effects. This information could then be 

the basis for the initial governmental response under the push 

syslem and could greatly enhance the effectiveness of that 

response. Current technology, particularly that based on geographic information systems (GIs), would easily support such 

an application (Wentworth and others, 1991). 

In addition to helping integrate the research community 

into the response under the Plan, deliberate advance planning can support the needs of the earth-science community 

itself. Given a necessary research program of observation, 

evaluation, and analysis after a major earthquake, preplanning 

is useful to: (1) assign people to field investigation teams, (2) 

assign a Scientist-in-Charge of USGS operations and liaison 

stalf to coordinate operations with other research institutions 

and groups, (3) assign a Science Advisor, (4) allocate resources, (5) identify and organize equipment, procedures, and 

facilities for rapidly compiling, correlating, evaluating, and 

interpreting observations, (6) assign priorities to missions and 

tasks, (7) organize response to the media, and (8) avoid duplication of effort while ensuring that all important aspects of 

the problem are covered. 

Following the Loma Prieta earthquake, it became necessary for the USGS to coordinate field operations with numerous people from other research institutions and disciplines, 

including geologists and engineers making field observations 
EARTH SCIENCE, EARTHQUAKE RESPONSE, AND HAZARD MITIGATION D87 

of ground-failure effects, engineering seismologists deploying arrays of strong-motion recorders, and geodesists and 

geologists conducting major, cooperative surveying efforts 

to help evaluate the situation and assess the further risks from 

incipient fault conditions in the region. Arrangements were 

made quickly for commercial air reconnaissance services 

using funds previously allocated for other research projects. 

Had such missions been identified under the Plan (perhaps as 

an integral part of ESF-5, Damage Information), it is possible that these services could have been funded under the 

Stafford Act. 

A curious feature of the Loma Prieta earthquake was its 

failure to produce surface rupture along the San Andreas Fault 

(U.S. Geological Survey Staff, 1990). The surface cracks and 

crevasses that formed throughout the epicentral region were 

found to be only secondary expressions of the primary faultplane rupture at depth, many of them landslide features and 

secondary breaks in near-surface rocks. Such features have 

different implications for the nature of the earthquake and its 

associated potential hazards. From a policy standpoint, the 

locations and distribution of secondary breaks in near-surface 

rocks may have implications for evaluating California's 

Alquist-Priolo Special Studies Zones (California, 1972) in 

the region: Should the secondary breaks be considered active 

faults in the context of land-use zoning? Is the pattern of these 

breaks recurrent? Can the Special Studies Zones Act 

effectively deal with the style of ground fracturing observed 

following the Loma Prieta earthquake? 

The Loma Prieta earthquake reactivated many large 

landslide deposits and caused other slope failures. Many of 

these, particularly along highways and coastal bluffs, continued 

to move and collapse after the earthquake. Because of these 

observations and the imminent onset of California's rainy 

season, which could exacerbate the landslide problem, the 

USGS issued warnings and advisories about landslides in the 

days and weeks following the earthquake. Many of the 

warnings were adapted from standardized warning messages 

developed during the mid- 1980's by the USGS for rainfallinduced landslides. The concern about slope instability after 

the Loma Prieta earthquake led to longer term monitoring of 

hillslopes and coastal bluffs throughout Santa Cruz County. 

The County was rezoned with respect to requirements for new 

construction and for rebuilding and repair of damaged 

structures (County of Santa Cruz, written commun., 1989). A 

landslide project for Santa Cruz County was developed from 

recommendations of the Hazard Mitigation Survey Team 

(Federal Emergency Management Agency, 1990, p. 30-3 1) 

and became a cooperative venture among FEMA, USACOE, 

USGS, Santa Cruz County, the California Division of Mines 

and Geology, the University of California at Santa Cruz, and 

private contractors (Technical Advisory Group on the Santa 

Cruz Geologic Hazard Investigation, 1991). Later, the State 

of California mandated long-term, statewide mapping of 

hazards for liquefaction, ground shaking, and landslides 

(California, 1990). 

The USGS and the earth-science community in general have 

an important role to play with regard to informing the public. 

This role includes the obligation to translate and transfer research results and scientific observations about particular 

earthquakes and associated risks to the public in a clear and 

understandable way. Plans for responding to public inquiries 

following earthquakes can build upon past efforts. A popular 

brochure issued soon after the Loma Prieta earthquake (Ward 

and Page, 1989) and a subsequent, widely distributed newspaper insert (U.S. Geological Survey, 1990) contained excellent information on responding to earthquake hazards and 

evaluating personal risks. To accomplish such information 

transfer effectively, it is important in time of disaster that the 

earth-science community quickly agree on the fundamental 

facts about the earthquake and speak with one voice, particularly on the basics regarding risks to the public. Vigorous scientific debate should, of course, be carried out at the appropriate times and places, with the arguments and conclusions 

summarized by a public affairs team. The public may readily 

accept the notion of a healthy, informed dialogue but may be 

uneasy with acrimonious disputes, perhaps overemphasized 

by media predisposed to reporting conflicts. Fortunately, cooperation was more prevalent than controversy among earth 

scientists following the Loma Prieta earthquake. 

It is noteworthy that about 10 percent of the USGS employees involved in response to the Loma Prieta earthquake 

were formally engaged in public outreach activities for the 

agency, and most others engaged in some ad hoc form of outreach activity. Much of this activity stemmed from impromptu 

press contacts in the field and telephone contacts while in the 

office. Although formal press conferences were set up on a 

regular basis by the USGS Public Affairs Office, these satisfied only part of the continuous demand for information. 

In the response to future, more severe earthquakes, all the 

activities discussed above, plus others, will likely have to take 

place, and shortcomings of earth-science response implied in 

the preceding text are likely to be greatly magnified unless 

we are better prepared. An organized scientific response plan 

could greatly facilitate rapid transition to a disaster-response 

footing. Such a plan should be flexible but comprehensive, 

outlining general guidelines, missions, and assignments and 

identifying resources and personnel. The plan should provide 

managers with the flexibility to make decisions and accommodate particular circumstances. Internal planning for the 

USGS should coordinate with the Federal Plan and with State 

plans to the extent possible. 

THE STATEIFEDERAL HAZARD 

MITIGATION SURVEY TEAM 

After the President officially declares a disaster, the Federal and State governments jointly form a Hazard Mitigation 

Survey Team (HMST). This team is composed of Federal, 
D88 RECOVERY, MITIGATION, AND RECOVERY 

State, and local government officials, and is charged with 

evaluating all aspects of response and recovery and recommending mitigation measures. The recommendations are then 

turned over to State and local governments and must be considered in Federally. mandated disaster plans as a condition 

for receiving Federal disaster relief funds. The authors served 

on the HMST for the Loma Prieta earthquake and were able 

to draft recommendations and overall content for the team 

report (Federal Emergency Management Agency, 1990). That 

report is a blueprint for reducing earthquake hazards in California and is a good example to show the value of having 

scientific input from the outset. The authors were able to 

monitor information about the causes and effects of the earthquake through activities and reports of USGS scientific staff 

and to condense this information into advice on immediate 

and long-term needs for disaster reduction. These needs were 

translated into written statements of work elements, including scientific background, assignment of entities to do the 

work, designation of possible sources of funding, and work 

schedules. Such recommendations generally require significant scientific input on issues such as landslide hazards, sitespecific shaking hazards, coastal bluff hazards, liquefaction 

hazards, and seismic criteria for building codes. 

The overall influence of the HMST recommendations on 

new legislation would probably be very difficult to determine. 

Nonetheless, the continuing work for seismic safety by the 

diverse partnership of professional communities reflected in 

the HMST report illustrates the persistence required to effect 

new legislation on hazard reduction. 

COMMUNICATIONS 

The most important requirement for interacting among various agencies and institutions during the response to a disaster situation is the capability to communicate. Communications systems must be rapid, reliable, and sufficiently robust 

to remain operational through the earthquake. As demonstrated during the Loma Prieta earthquake response, the commercial telephone system does not meet these requirements. 

It is susceptible to saturation by overuse, damage to lines and 

equipment, and, for some systems internal to an institution, 

to power failures. Connectivity of communications links to 

other organizations should be specified in agency response 

plans and coordinated with the Federal Plan through deliberate planning. 

Communications systems used during disaster response 

must provide for information flow between field locations, 

from field sites to regional headquarters and thence to national headquarters, from those headquarters to other agencies conducting response operations, and to the general public through the media. Because large amounts of data may 

need to be transmitted rapidly, provision must be made for 

systems to handle data flow as well as voice reports. Systems 

must employ equipment that is in place and used on a regular 

basis to ensure operability when needed during an actual 

emergency. Personnel should be trained in the operation of 

this equipment and should practice using it during local and 

regional earthquake response exercises. The only outside communications link with the USGS that is presently provided 

for under the Plan is between the National Earthquake Information Center in Golden, Colorado, and FEMA headquarters 

in Washington, D.C. This link serves for the primary notification from the USGS that a major earthquake has occurred 

and for providing additional information on that earthquake. 

Other links of this type are being developed. 

An agency or institution can ordinarily establish communications for field operations using its existing assets. Communiications to the general public through the news media 

are u~sually effected using those media's facilities. However, 

communications with other responding agencies, other than 

by commercial telephone, are not part of the normal course 

of affairs for a research institution. Thus, in order to mount 

an effective response, communications between responding 

agencies must be prepared through advance planning. A communication link should be established as soon as possible to 

connect the Science Advisor at the Disaster Field Office (DFO) 

to USGS field headquarters. The DFO can then distribute 

messages from the USGS to the various Emergency Support 

Functions (ESF's) as necessary. For this to be effective, message routing must be understood and the authority to release 

messages must be in place. At the DFO, FEMA normally sets 

up tlie Mobile Air Transportable Telecommunications System (MATTS). Among other features, MATTS continuously 

displlays on a large television monitor a running account of 

significant response actions, status reports, and other information valuable to managing the ESF operations. Another 

monitor may display a regional map in a Geographic Information System (GIs), keyed to a variety of demographic data, 

that can be altered and viewed at different scales. ESF's can 

enter data directly into the text stream of the first display using systems on personal computers. This can be an effective 

method of disseminating up-to-the-minute scientific information, such as aftershock probabilities, locations and conditions at ground-failure sites, and risk estimates, to responding agencies. 

These communications links in a disaster response are best 

established using satellite-based systems for maximum flexibility and survivability. 

CONCLUSIONS AND 

RECOMMENDATIONS 

The response of the earth-science community to the Loma 

Prieta earthquake was helped by several favorable factors: 

the proximity of many scientists and their resources to the 

affected area; significant, rapid volunteerism; excellent 

weat her conditions; continuous media coverage; the relatively 
EARTH SCIENCE, EARTHQUAKE RESPONSE, AND HAZARD MITIGATION D89 

minor damage from such a large earthquake; and the extensive knowledge about regional geological conditions derived 

from decades of intensive investigations. In future earthquakes 

in this same region and in other regions, many of these favorable conditions might not be met. Therefore, any insufficiencies of the earth-science response identified from the Loma 

Prieta earthquake experience could be greatly magnified in 

another large earthquake unless careful advance planning is 

done. 

The U.S. Geological Survey became the primary coordinating agency for earth-science response to the Loma Prieta 

earthquake because of its well-known presence in the affected 

region, not because of any official policy. It is likely that the 

USGS will assume a similar role in future large earthquakes 

in the San Francisco Bay area. The agency should therefore 

investigate the responsibilities of that role, both internally and 

in consultation with potential cooperators in disaster response, 

so as to be fully prepared. The USGS needs to initiate or participate strongly in earthquake-response exercises like RESPONSE-89, both to teach and to learn the roles of scientific 

investigators as responders in the aftermath of a large earthquake. 

The primary governmental agencies charged with disaster 

response should clarify the nature of their charges and their 

responsibilities to each other and set these out explicitly 

through formal agreements and plans. Such agreements will 

help reduce misunderstandings about responsibilities and jurisdictions and provide both the public and the agencies with 

clearer and more complete information. The USGS (and other 

scientific research organizations) have not generally seen 

themselves in primary disaster-response roles. They should 

now recognize that they do have such roles and should involve themselves more directly with the Federal Emergency 

Management Agency, the U.S. Army Corps of Engineers, and 

the California Governor's Office of Emergency Services. After a major earthquake, these agencies need frequent scientific briefings, and they can in turn provide funding, equipment, people, geotechnical data, and other benefits to the 

earth-science research community. One major contribution 

that the earth science community could provide is immediate 

notification of the parameters and expected effects of an earthquake. This information can then form a basis for initial response using preassigned missions (the "push system"), without waiting for direct reports of damage and casualties. 

Scientific agencies like the USGS should make formal organizational connections between their research capabilities 

and the needs of disaster response. To do this they should 

develop internal response plans; participate through the National Earthquake Hazards Reduction Program in the Plan 

for Federal Response to a Catastrophic Earthquake (now the 

Federal Response Plan); identify selected scientists for participation on Hazard Mitigation Survey Teams and public affairs teams; prepare warning statements and practice issuing 

warnings; and draw from recent experiences during responses 

to disasters to undertake formal advance planning. 

The U.S. Geological Survey should ensure that its communications facilities are disaster resistant and should participate in systems like the Mobile Air Transportable Telecommunications System of FEMA through the Disaster Field 

Office during active disaster response. The interchange of realtime information that this will allow with governmental Emergency Support Functions and people who must make the immediate decisions about what to do next in critical situations 

would have many advantages to the earth-science community and to society. 

ACKNOWLEDGMENTS 

The authors are grateful to Robert D. Brown, Paula L. Gori, 

William J. Kockelman, David M. Perkins, William H. Prescott, 

Randall G. Updike, Joanne M. Nigg, and anonymous reviewers for helpful reviews and constructive comments. 

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