The Lorna Prieta, California, Earthquake of 

October 17, 1989-Public Response 

PATRICIA A. BOLTON, Editor 

SOCIETAL RESPONSE 

DENNIS S. MILETI, Coordinator 

UeSe GEOLOGICAL SURVEY PROFESSIONAL PAPER 1553-B 

-- - 

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1993 
DEPARTMENT OF THE INTERIOR 

MANUEL LUJAN, JR., Secretary 

U.S. GEOLOGICAL SURVEY 

Dallas L. Peck, Director 

Any use of trade, product, or firm names in this publication is for 

descriptive purposes only and does not imply endorsement by the 

U.S. Government 

Manuscript approved for publication, May 26, 1992 

Library of Congress Cataloging in Publication Data 

The Loma Prieta, California, earthquake of October 17, 1989. 

(U.S. Geological Survey professional paper) 

Includes bibliographical references. 

Contents: Strong ground motion and ground failure-ch. F, Marina District. Societal 

response-ch. B, public response. 

1. Earthquakes-California-Loma Prieta Region. 2. Earthquakes-California-San Francisco 

Bay Area. 

QE535.2.U6L66 1992 551.2'2'097946 92-32287 

-For sale by the Book and Open-File Report Sales, U.S. Geological Survey, 

Box 25286,Denver, CO 80225 
CONTENTS 

Citizen participation in emergency response---------------- 

By Paul W. 07Brien and Dennis S. Mileti 

Public response to aftershock warnings ..................... 

By Dennis S. Mileti and Paul W. 07Brien 

Building content hazards and behavior of mobilityresidents --------- ................................ 

By Mansour Rahimi and Glenn Azevedo 

Earthquake preparedness behavior of students and 

nonstudents-------------------------------------------------- 

By John-Paul Mulilis and T. Shelley Duval 

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

SOCIETAL RESPONSE 

PUBLIC RESPONSE 

INTRODUCTION 

By Patricia A. Bolton, 

Battelle Human Affairs Research Center, Seattle, Wash. 

INTRODUCTION 

Major earthquakes provide seismologists and engineers 

an opportunity to examine the performance of the Earth 

and the man-made structures in response to the forces of 

the quake. So, too, do they provide social scientists an 

opportunity to delve into human responses evoked by the 

ground shaking and its physical consequences. The findings from such research can serve to guide the development and application of programs and practices designed 

to reduce death, injury, property losses, and social disruption in subsequent earthquakes. This chapter contains findings from studies focused mainly on public response to the 

Loma Prieta earthquake; that is, on the behavior and perceptions of the general population rather than on the activities of specific organizations or on the impact on 

procedures or policies. A major feature of several of these 

studies is that the information was collected from the population throughout the Bay area, not just from persons in 

the most badly damaged communities or who had suffered 

the greatest losses. This wide range serves to provide comparisons of behavior for those most directly affected by the 

earthquake with others who were less directly affected by 

it but still had to consider it very "close to home." 

Three of the six studies reported in this chapter involved 

the collection of data from random samples of the general 

population in areas affected by the earthquake (Bourque and 

others; O'Brien and Mileti; Mileti and O'Brien). A fourth 

examined the experiences of a sample of persons with 

major mobility limitations (Rahimi). One study involved 

the comparison of pre-earthquake and post-earthquake 

thinking about preparedness for samples of college students 

in conjunction with the Loma Prieta earthquake and other 

recent earthquakes (Mulilis and Duval). The sixth study 

provides a description of the emergency housing needs, 

initial solutions, and responses to the solutions in one of the 

hardest hit counties, Santa Cruz (Bolin and Stanford). 

All of these studies serve to verify the central finding of 

social scientists across several decades of disaster studies: 

during and after an earthquake, most individuals and families will engage in rational and directed behavior. That is, 

they will try to figure out what is happening or has happened, what it means to them, and what their next action 

will be. It has been the objective of earthquake education 

efforts to promote behavior that will also be adaptive to the 

conditions, as changed by the earthquake. Several of the 

studies provided evidence of adaptive behavior in the populations studied, such as individuals and families engaging 

in protective actions during the shaking (Bourque and others; Rahimi), creating or finding alternative shelter until 

they can determine what is safe (Bourque and others; Bolin 

and Stanford), becoming more interested in preparedness 

measures (Mulilis and Duval), helping others who have experienced damage (O'Brien and Mileti), or attending to 

warnings about potential aftershocks (Mileti and O'Brien). 

At the same time, the way in which the individual personally experienced the earthquake was a factor in the likelihood that the most adaptive response would be made. 

Examples of this are findings such as the following: people 

who were not particularly frightened by the earthquake 

were less likely to seek further information about what was 

going on (Bourque and others); those disabled persons who 

did not perceive themselves as directly vulnerable to the 

shaking were less likely to actively engage in protective 

behavior (Rahimi); persons who did not experience damage either to their own home or immediate neighborhood 

were less likely to provide assistance to earthquake victims 

elsewhere (O'Brien and Mileti); persons without direct experience with damage were less likely to take seriously the 

warnings provided about potential damaging aftershocks 

(Mileti and O'Brien); and views on preparedness among 

college students were not likely to change after an earthquake if the earthquake was not perceived as particularly 

damaging (Mulilis and Duval). Since it is imperative that 

people who live in hazardous regions understand the nature 

of the earthquake threat, even before experiencing an earthquake, these findings reinforce the belief that it is important to engage in programs to make the built environment 

resistant to earthquake damage, and to educate the population about what they can do to protect themselves. 

Two studies also touched on issues surrounding evacuation behavior following earthquakes. While many of our 

relief policies are designed to serve persons who have left 

their dwelling after the earthquake because it is too 
B2 PUBLIC RESPONSE 

damaged to occupy, two of the studies included evidence 

that post-earthquake evacuation is more complex than that 

(Bourque and others; Bolin and Stanford). There will be 

persons who leave their homes because of damage to 

property or utilities. There also will be those who experience comparable levels of damage to their home but who 

choose to remain in or by their homes, as well as those 

who evacuate despite having experienced no overt property damage sufficient to cause evacuation but are experiencing personal stress about the event. This information is 

important for the design of post-earthquake emergency assistance and relief efforts. So too are the insights provided 

in the documentation of the sources of the conflict that 

arose in Santa Cruz County communities related to housing alternatives where populations were ethnically or socially diverse (Bolin and Stanford). 
THE LOMA PRIETA, CALIFORNIA, EARTHQUAKE OF OCTOBER 17,1989: 

SOCIETAL RESPONSE 

PUBLIC RESPONSE 

HUMAN BEHAVIOR DURING AND IMMEDIATELY AFTER THE 

EARTHQUAKE 

By Linda B. Bourque, University of California, Los Angeles, 

Lisa A. Russell, University of California, Los Angeles, and Southern California Earthquake Preparedness Project, 

James D. Goltz, Southern California Earthquake Preparedness Project 

CONTENTS ABSTRACT 

Introduction .......................................... ------------- 

References cited ------------- - ..................... ----- ---------- 

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We used random digit dialing procedures to select a 

sample of 83 residents of San Francisco and Oakland, 122 

residents of Boulder Creek, Santa Cruz, and Watsonville, 

and 451 residents of the remaining areas of San Francisco, 

Alameda, Santa Cruz, Santa Clara, and San Mateo Counties. 

They were interviewed an average of 224 days after the 

earthquake. Analyses examine where respondents were, 

who they were with, and what they did at the time of the 

earthquake; their exposure to radio and television during 

and immediately after the earthquake; the effect of loss of 

utilities and damage to homes and personal property; and 

evacuation behavior after the earthquake. 

INTRODUCTION 

Although the work of geologists, engineers, and seismologists has expanded our knowledge of earthquakes substantially since the San Fernando earthquake of 1971, 

earthquakes remain the least predictable of the natural disasters. Moreover, systematic documentation of human behavior during and immediately after earthquakes remains 

an understudied area. The few existing studies are primarily anecdotal, observational reports by persons who entered 

the affected area to provide services after the earthquake. 

Such reports usually focus on self-identified victims who 

presented themselves to a central location for assistance or 

depend on observations made by a researcher or service 

provider within the disaster area. In other cases the collection of data on human experience and behavior was incidental, as part of a different study objective (for example, 

Bolin and Bolton, 1986). Limited exceptions include studies by Bourque and others (1973) after the 1971 San Fernando earthquake, Tierney (1985) after the 1982 Coalinga 

earthquake, Mileti and others (1990; unpub. data) after the 

prediction at Parkfield, California, and the 1989 Lorna 
B4 PUBLIC RESPONSE 

Prieta earthquake, and Goltz and others (1992) after the 

1987 Whittier Narrows earthquake. 

In spite of the limited systematic literature available, 

policymakers and practitioners' often are formally mandated and informally pressured to develop programs that will 

reduce death, injury, and losses to buildings, businesses, 

information systems, and social institutions such as 

schools, hospitals, and lifelines. Many of these policies 

and procedures, by necessity, have been developed in the 

absence of relevant information. For example, mass media 

have often been considered a powerful source of disseminating information both before and after a disaster, yet remarkably little information is available about whether and 

when people use media for disaster-related information. 

Procedures have been developed which, when followed, 

are thought to reduce risk of injury and property damage, 

but few studies have evaluated the extent to which persons 

know about or follow such recommendations or the effectiveness of the recommended procedures in meeting objectives. Similarly, numerous groups have invested significant 

time and money to develop an extended emergency infrastructure to assist persons who are displaced at the time of 

a disaster. Again, however, these programs have been developed in the absence of any systematic information 

about who evacuates, why they evacuate, where they go, 

or the length of time they remain away from their homes. 

Studies such as this provide information to evaluate the 

success of some of the existent programs and policies, 

while simultaneously suggesting fruitful areas for future 

extension, reduction, or change. This report systematically 

examines where people were, who they were with, what 

they did, and what happened to them as a result of the 

Loma Prieta earthquake. We were particularly interested in 

examining what people did during the earthquake, their 

use of broadcast media during and immediately following 

the earthquake, and the reasons given for evacuating their 

homes after the earthquake. Following a brief overview of 

relevant literature, we describe the methodology of the 

study, present findings pertinent to the questions under examination, and discuss some implications for policy and 

practice. 

 or our purposes, practitioners include all those individuals 

and groups who are involved in the delivery of services before, 

during, and after a disaster. Some of these groups, such as the 

staff of the Bay Area and Southern California Earthquake 

Preparedness Projects and the Red Cross, identify themselves as 

specialists in disaster relief on a continuous basis. Others, such 

as police, firefighters, and medical personnel, receive special 

training in disaster relief and emergency response activities as a 

result of the jobs they hold and consciously identify themselves 

as emergency response practitioners under certain circumstances. 

Others, such as school teachers and building inspectors, receive 

little direct training in emergency response and may identify with 

this group of practitionsers only after a disaster occurs. 

PAST STUDIES 

Although some studies acknowledge the importance of 

describing human behavior during and immediately after 

disasters, few systematically describe this behavior; nor 

has this behavior been examined within the social and 

physical context in which it occurs (Quarantelli, 1988; 

Goltz and others, 1992). 

RESPONSE BEHAVIOR 

It is reasonable to assume that human response options 

at the time of an earthquake (staying in place, seeking protection, going to others, and so forth) varies with the person's physical situation and proximity to the earthquake's 

epicenter and that selection of a response may be influenced by others who are present at the time. Several studies support this assumption. 

In studying behavior during Kansas tornados, the National Opinion Research Center found that almost all preevent, event, and post-event activities were centered on 

helping people rather than preserving property (Quarantelli, 1988). How adults reacted was particularly influenced 

by whether they were with other adults, children, or were 

alone and was a major factor in adaptive, protective responses. Males tended to assume active leadership roles 

when they were the only males present, and females tended to assume leadership roles in the presence of children. 

Male household heads with dependent children, in particular, tended to display the most well-suited and sheltering 

behavior toward self and others. Overall, response behavior was characterized as controlled and adaptive-frenzied 

escape, hysteria, and emotional paralysis were extremely 

rare, if not entirely absent. 

Similar conclusions were reached by Goltz and others 

(1992), who analyzed the behavior of Southern California 

residents after the 1987 Whittier Narrows earthquake. 

Taking cover in a doorway, hall, or under furniture during 

the earthquake was the modal response for those either at 

home (43 percent) or at work (40 percent), and pulling to 

the side of the road and stopping was the modal response 

for those who were driving (46 percent). Of those at 

home or at work, 20 percent reported remaining in place, 

whereas 18 percent of those at work and only 9 percent 

of those at home recalled going outside. Nearly half of 

those who went outside reported exiting by running. For 

those at home, protective behavior increased with increased fear and in the presence of children, but not in 

the presence of other adults. Women sought protection 

more frequently than men. For those at work, taking cover was associated with higher expressed fear, being white 

and female, and being with others. Neither gender nor the 

presence of others was related to responses while driving, 

and there were too few respondents who were driving to 
HUMAN BEHAVIOR DURING AND IMMEDIATELY AFTER THE EARTHQUAKE 

assess any relationships with other salient demographic 

factors. 

MASS MEDIA 

Literature describing the relationship between the mass 

media (radio, television, and newspapers) and disasterresponse behavior has focused on the media's role in preevent risk perception and preparation as well as their role 

in disseminating post-event information and describing 

post-event needs. The mass media seem to intentionally 

underemphasize the potential threat of predicted or potential disasters, supposedly to protect people from their propensity for panic and maladaptive behavior (Goltz, 1989). 

Even when increases in perceived risk from an impending 

disaster are achieved as a result of a mass media campaign, the result is not necessarily a uniform or consistent 

increase in disaster preparedness (Mileti and Nigg, 1984; 

Hirose, 1986). Evaluations of several mass communication 

campaigns have reported that the translation of a mass 

media message into individual attitude and behavior 

change is largely dependent on its passage through interpersonal communication networks (Turner and Heller Paz, 

1986; Ball-Rokeach and Cantor, 1986). Although largely 

ignored by disaster researchers and planners, these interpersonal networks deserve further examination. 

The media's somewhat paternalistic attempt to "protect" 

the public from disaster warnings is noticeably juxtaposed 

against the tone of post-disaster reporting. At this stage, the 

mass media have been accused of sensationalizing deaths 

and injuries and overestimating the extent of property damage (Mileti and Nigg, 1984; Hiroi and others, 1985; Palacios and others, 1986). It has also been suggested that the 

mass media are partially responsible for feeding the myth 

that disasters inevitably and naturally result in panic behavior as well as increases in criminal behaviors such as 

looting (Hiroi and others, 1985; Mileti and Nigg, 1984). 

While other research studies and numerous review articles 

have stated repeatedly that people rarely panic in response 

to a disaster (Wenger and others, 1975; Mileti and Nigg, 

1984; Goltz, 1989), the idea that panic is common continues to be perpetuated-often by the mass media. 

To fully examine the media issues outlined here, disaster 

researchers need to examine the characteristics of individuals who do and do not use the media before, during, and 

after a disaster. Few sophisticated studies exist which examine the relationship between the mass media and the 

community in the context of disasters. An exception is the 

study of media use after the 1980 eruption of Mount St. 

Helens (Hirschburg and others, 1986). As predicted by 

media dependency theory (Ball-Rokeach and Cantor, 

1986), media use did not differ with age and gender, because of respondents' common need for information regarding the disaster. 

UTILITIES 

With some exceptions, the disaster literature has not addressed the effects of utility damage and loss on a community. Recent contributions by Nigg (1990) and Tierney 

(1991) highlight the importance of functioning utilities or 

"lifelines" to a community's ability to respond and recover 

from a disaster. Utility damage most affected gas, sewer, 

and water systems following the 1983 Cwalinga earthquake (Tierney, 1985), the operations of which may significantly impact the health and safety of a community's 

residents (Nigg, 1990). Whether utilities continue to function affects a person's ability to prepare meals, drink uncontaminated water, keep warm, wash utensils and clothes, 

bathe, receive messages via electronic media, or communicate with others. Inability to perform these basic activities 

often motivates people to evacuate their homes after a disaster (Bolin and Stanford, 199 1). 

Nigg (1990) and Tierney's (1991) case studies of disaster-struck communities illuminate the advantages and disadvantages of functionally interconnected utility and 

lifeline failures. Among the drawbacks, for example, is 

that power failure often impacts the functioning of water, 

sewage, and communication systems. On the other hand, 

organizational utility interdependence was found to facilitate the recoveries of gas and electricity after the Loma 

Prieta earthquake (Tierney, 1991). However, Tierney also 

noted that such centralization of control can be a detriment 

if the disaster severely affects the control center and its 

internal recovery efforts. The minimization of post-disaster 

loss of utilities has been attributed to the coordination of 

disaster preparedness efforts between a community and its 

regional utility companies (Tierney, 1991). 

DAMAGE 

Reported post-disaster damage estimates are usually 

those of officials rather than of individual homeowners 

(Drabek, 1986); an exception to this trend is the national 

household survey conducted by Rossi and others (1983). 

Rossi and his colleagues surveyed victims of natural disasters which occurred between 1970 and 1980. The national 

estimate of the total annual household costs incurred as a 

result of earthquakes was $400,000,000; the largest percentage of this amount was due to losses of real and personal property. Three-quarters of the earthquake events 

experienced resulted in structural damage to the respondents' homes. The sociodemographic characteristics of the 

respondent and other household characteristics were not 

associated with the estimated cost of damage; the extent of 

regional damage was significantly associated with the dollars needed for household damage repair. 

Damage to homes following an earthquake can be related 

to variables such as the type of structure and construction 
B6 PUBLIC RESPONSE 

of the home, the type of soil supporting the home, the 

home's proximity to other damaged structures, and the 

home's proximity to the epicenter (Tierney, 1985; Bolton 

and Orians, this volume; Bolin and Stanford, this volume). 

Some of these items are amenable to either structural or 

nonstructural mitigation. The type and extent of home 

damage is often related to both the actual and the perceived future safety of its inhabitants, the continued and 

safe functioning of utilities, the official evacuation orders, 

and the inhabitant's decision to evacuate. 

EVACUATION 

According to Mikami and Ikeda's (1985) post-disaster 

survey of human response to disasters, evacuation decisionmaking is based, in part, on the perception of threat, 

exposure to evacuation advice, family and demographic 

characteristics, and community preparedness. Early evacuation is related to acute perceptions of direct threat, repeated exposure to evacuation advice, location of home, and 

past disaster experience. 

Mikami and Ikeda argued that the threat of disaster is 

understood in the setting of daily life and may be underestimated when considering evacuation (see also Quarantelli, 1984). They found that compliance with evacuation 

advice varied from 13 percent to 96 percent, depending 

on the community sampled. Past research suggests that 

people respond to warnings, in part, because the warnings effectively arouse concerns about personal or family 

safety. To our knowledge, comparable studies have not 

examined the role that pre-disaster psychological distress 

may play in heightening arousal which results in possibly 

dysfunctional evacuation. Comparable studies are needed 

to describe factors, such as psychological distress, that 

may predict evacuation behavior under varying conditions. We believe that a better understanding of the motivations behind evacuation behavior will influence the 

quality and quantity of future levels of community preparedness for disasters in general, and for earthquakes in 

particular. 

STUDY OBJECTIVE 

Our objectives in these analyses were to describe where 

people were, who they were with, and what they did during and immediately after the Loma Prieta earthquake; 

what damage, if any, occurred to their homes and personal 

property; and whether and why they evacuated their 

homes. In particular, we examined both the geographic area and type of place-home, school, work, public place, 

or in transit-where respondents were at the time of the 

earthquake and how their location and companions, if any, 

determined their actions at that time. 

We also were interested in determining whether people 

made efforts to protect themselves or, at least, to avoid 

harm, and how such decisions differed with proximity to 

epicenter, location, and the presence of other people. We 

also wanted to know whether people sought information 

from broadcast media (radio and television) during and 

immediately after the earthquake, and whether such information seeking varied with geographic location, type of 

place, and a person's companions at the time of the 

earthquake. 

We describe the amount of damage to homes, personal 

property, and utilities that our respondents reported, and 

the extent to which reported damage differed with proximity to the areas of more intense shaking. Finally, we 

describe the number of persons who left their homes after 

the earthquake, their reasons for evacuation, and the extent to which evacuation behavior was affected by proximity to the epicenter, damage, loss of utilities, presence 

of other people, and expressions of fear at the time of the 

earthquake. 

SAMPLE 

Between April 29, 1990, and August 1, 1990, 30-minute 

telephone interviews were conducted by staff at the Institute for Social Science Research at the University of California, Los Angeles. Modified random digit dialing (rdd) 

procedures were used to obtain a representative sample of 

656 persons residing in households in San Francisco, Alameda, Santa Cruz, Santa Clara, and San Mateo Counties 

(Frankel, 1 983; Sudman, 1 983). To increase the efficiency 

of the sample and to insure that at least 75 persons were 

interviewed within each of the areas known to be most 

affected by the earthquake, intentional oversampling was 

conducted in the two areas where modified Mercalli intensities (as assessed in monitored buildings) equalled 8 or 9: 

the northeast edge of the San Francisco Peninsula and 

Oakland, and the Boulder Creek-Santa Cruz-Watsonville 

area. Within contacted households, all persons over age 18 

who resided in a household in the five-county area on the 

day of the earthquake were enumerated and one resident 

was randomly selected for interview using the Kish procedure (Kish, 1965). Across the total sample, 35 potential 

respondents were lost because they spoke languages other 

than English, usually Asian. 

A total of 83 residents of San Francisco-Oakland, 122 

residents of Boulder Creek-Santa Cruz-Watsonville, and 

451 residents of the rest of the five-county area were interviewed (table 1). The probability that residences (with 

telephones) were selected was 5 in 10,000 for San Francisco-Oakland, 3 1 in 10,000 for Boulder Creek-WatsonvilleSanta Cruz, and 5 in 10,000 for the rest of the five-county 

area. Thus, stratification did not increase the probability 

that households in the northeast edge of the San Francisco 
HUMAN BEHAVIOR DURING AND IMMEDIATELY AFTER THE EARTHQUAKE B7 

Table 1.-Sampling characteristics by sample strata for the 

earthquake (unweighted sample) 

[n = total number; pet. = percentage of total number; p = 

significance level for analysis of variance] 

Outcome 

Area San 

Francisco/ Five county Santa Cru n Pct. n Pct. n Pct. 

Telephone numbers 

generated 1,100 -- 270 

Disconnected 218 19.8 76 

Nonresidential 159 14.5 60 

Number changed 25 2.3 3 

No qualified respondent 17 1.5 6 

FAX machine 20 1.8 3 Modem 6 0.5 4 

Total unusable 445 40.5 152 

Total usable 655 59.5 118 43.7 164 

Refusal 116 17.7 14 11.9 25 

Language barrier 27 4.1 5 4.2 3 

Resident incapable 11 1.7 1 0.8 3 

No answer (9+ attempts) 24 3.7 8 6.8 6 

Answering machine (7+ attempts) 26 4.0 7 5.9 5 

Completed interviews 451 68.9 83 70.3 122 

Response rate (pet. ) 68.9-74.4 70.3-80.6 74.4 

Probability household selected 5/10,000 5/10,000 31/10,000 

Weights 1.00 0.96 0.16 

No. of days since quake* 226 -- 217 -- -- 223 -- PC~. interviewed in Spanish -- 1.3 4.8 -- 1.6 

Pct. willing to be reinterviewed 86.7 -- 86.7 -- 92.6 -- 

Mean estimated Mercalli at home** 6.7 -- 8.3 -- 8.2 -- Mean estimated Mercalli where resident was**' 6.7 -- 7.3 -- 7.9 -- 

Excludes 23 residents who were outside the five-county area at the time of the earthquake. 

Peninsula and Oakland would be in the sample. Response 

rates were between 70.3 percent and 80.6 percent in San 

Francisco-Oakland, between 74.4 percent and 79.7 percent 

in Boulder Creek-Watsonville-Santa Cruz, and between 

68.9 percent and 74.4 percent in the rest of the five-county 

area. 

In San Francisco-Oakland, interviews were conducted an 

average of 217 days after the earthquake; 4.8 percent were 

conducted in Spanish. In Boulder Creek-Watsonville-Santa 

Cruz, interviews were conducted an average of 223 days 

after the earthquake with 1.6 percent conducted in Spanish, whereas in the rest of the five-county area, interviews 

were conducted an average of 226 days after the earthquake with 1.3 percent conducted in Spanish. 

the sample. Third, persons whose telephones were disconnected as a result of the earthquake or whose households 

were destroyed as a result of the earthquake and who either left the area or remained unaccessible by telephone at 

the time of the interview were underrepresented in the final sample. These three groups of people will subsequently be referred to as those in categories 1 through 3, 

respectively. 

As shown in table 1, respondents who matched the characteristics of category 3 were least likely to be underrepresented in this data set. The total usable numbers identified 

in this sample ranged from 43.7 percent for San FranciscoOakland to 60.7 percent for Santa Cruz. These percentages 

are comparable to national rates and higher than rates obtained in Los Angeles County after the 1987 Whittier Narrows earthquake, where 39.7 percent of the telephone 

numbers in the high-impact area and 31.4 percent of those 

generated in the rest of the county were usable (Goltz and 

others, 1992). 

Categories 1 and 2 above were more problematic. Clearly, itinerant farm workers in the Watsonville area and persons in single-room-occupancy hotels (SROs) in the San 

Francisco-Oakland area were underrepresented or not represented in this sample. Many of these persons would have 

been missed in a telephone survey at any time, because 

they did not reside in households with telephones; others 

probably lost access to telephones as a result of the earthquake. Other information suggests that these groups might 

have been disproportionately dislocated by the earthquake. 

For example, 40 percent of the 10,000 dwelling units destroyed or severely damaged in the earthquake were single 

room occupancy hotels (SROs) or other kinds of housing 

that displaced persons with low or moderate incomes (R.J. 

DeMonte, Region IX, Feb. 8, 1990 [written commun.] to 

J. Kemp, Secretary, U.S. Dept. of Housing and Urban Development), and only 24 percent of the 10,331 households 

that registered with the Red Cross for assistance were 

those of homeowners (Peggy Brutsche, written cornrnun., 

December 16, 1991). We hope that future comparisons of 

this sample with data available in the 1990 U.S. census 

will allow us to assess the extent to which residents of 

SROs, itinerant farm workers, and other groups were underrepresented in this data set. 

DATA COLLECTION 

SAMPLE LIMITATIONS 

The use of rdd to select the sample led to three concerns. First, persons who were homeless or who did not 

reside in households before the earthquake were significantly less likely to be represented in the final sample. 

Second, persons who resided in households without telephones before the earthquake and who remained without 

telephones after the earthquake were underrepresented in 

The questionnaire used for data collection was adapted 

from questionnaires developed by Turner and others 

(1986) and Bourque and others (1973) and largely replicated a questionnaire used to collect data from Los Angeles County residents after the 1987 Whittier Narrows 

earthquake (Goltz and others, 1992). Data were collected 

to assess the type and extent of response actions, including information about damage and injury to self and 
B8 PUBLIC RESPONSE 

others; decisions to evacuate; earthquake preparedness 

both before and after the earthquake; orientation toward 

and use of media after the earthquake; exposure to earthquake predictions; and contact with officials and agencies 

after the earthquake. Detailed information about household composition at the time of the earthquake and at the 

time of the interview, and other demographic information, 

were collected. 

Modifications made in the questionnaire developed after 

the Whittier Narrows study for use after the Loma Prieta 

earthquake reflected differences in residents' experiences 

during and after the two shocks or resulted from knowledge gained during the collection and preliminary analyses of data collected in Los Angeles. First and foremost, 

the civilian version of the Mississippi Scale for CombatRelated Posttraumatic Stress Disorder (Keane and others, 

1988) and questions that reflect suggestions made by Norris (1989) for the measurement of posttraumatic stress 

were added to the questionnaire. Second, to obtain a more 

. detailed measure of geographic location than is provided 

by telephone prefixes, information on each respondent's 

zip code of residence and, for those not at home, details 

of the respondent's location at the time of the earthquake 

were collected. Third, questions such as those on media 

usage and loss of utilities were modified to reflect differences in the two earthquakes. 

ANALYSIS 

Analyses in this report describe where people in the 

five-county Bay Area were at the time of the Loma Prieta 

earthquake, other people with them and their reported actions during the earthquake, respondents' passive and active exposure to media during and immediately after the 

earthquake, damage they experienced to personal property 

and homes, loss of utilities, and decisions to evacuate. We 

do not present data on preparedness behavior before or after the earthquake, exposure to earthquake warnings, or injuries, and we discuss respondents' psychological distress 

only as it relates to evacuation behavior. Information on 

injuries and psychological distress after the earthquake can 

be found in Bourque and others (1 99 1). 

INDEPENDENT VARIABLE: LOCATION 

The location of respondents and their homes relative to 

the epicenter of the earthquake was the independent variable in most of our analyses. The extent to which an individual physically "feels" and is moved around by an 

earthquake varies with proximity to the epicenter, characteristics of the soil and other geologic features, and the 

surroundings (indoors, outdoors, or in a car); if indoors, 

characteristics of the building and locations of furniture 

and other objects, and so forth. Modified Mercalli intensities (MMIs) were used to provide a rough indication of the 

extent of shaking that respondents and their residences experienced during the earthquake. MMI scores for the location of an individual's residence were incorporated into 

the procedures for selecting the sample (see section "Sample"), and three strata were created which varied in intensity of shaking as measured by MMIs. This three-category 

variable of sample strata was used as the independent variable in many of our analyses. 

At the time of the earthquake, only about half of our 

respondents were at home. For those at home, we assigned 

the score of the sample strata where the home was located: 

an MMI of 8 or 9 in northeast San Francisco, Oakland, 

Boulder Creek, Santa Cruz, and Watsonville; and an MMI 

of less than 8 in the rest of the five-county area. Persons 

who were not at home at the time of the earthquake were 

asked in what geographic area of the five counties they 

were when the event occurred. They were then assigned 

the MMI score for that area. A second three-category variable was then created to indicate in which of the three 

original strata (San Francisco-Oakland, Boulder CreekSanta Cruz-Watsonville, or the five-county area) a respondent was at the time of the earthquake. Sixty-six persons 

were in a different strata from where they lived: 20 residents of the five-county area were in San FranciscoOakland, 17 residents of the five-county area were in the 

Santa Cruz area, 13 residents of San Francisco-Oakland 

were in the five-county area, and 16 residents of the Santa 

Cmz area were in the five-county area. The sample was 

weighted (see following section) when this "location" variable was the independent variable in analyses. 

ANALYSIS STRATEGY 

Experiences and behavior were examined by magnitude 

of shaking experienced as described above, by standard 

demographic characteristics, and, when warranted, by other relevant variables. Descriptive analyses were conducted 

and are reported in the form of two- or three-way contingency tables using the chi-square statistic or one-way 

analysis of variance when appropriate. Chi-square tests 

were not calculated when a table contained excess numbers of small cells. In recognition of differences among 

the three sample strata in both demographic characteristics 

and earthquake experiences, sample strata were incorporated into all analyses in one of three ways: as the independent variable in an analysis, as a control variable, or with 

sample weights that accounted for the fact that residents of 

the Boulder Creek-Santa Cruz-Watsonville area were overrepresented when sample strata were combined. When 

weights were assigned, respondents in the Santa Cruz area 

received a weight of 0.16, those in San Francisco-Oakland 

a weight of 0.96, and those in the five-county area a 
\ 

HUMAN BEHAVIOR DURING AND IMMEDIATELY AFTER THE EARTHQUAKE B9 

weight of 1.00. The size of the weighted sample is 55 1. 

The title of each table in this report indicates whether a 

weighted or unweighted sample was used for the analysis 

reported. 

FINDINGS 

DEMOGRAPHIC CHARACTERISTICS 

Fifty-five percent of the respondents were female. On 

average, respondents were 46 years of age and had completed more than 14 years of schooling (table 2). Gender, 

age, and socioeconomic status as measured by modified 

Duncan scores (see Stevens and Cho, 1985) were comparable across the three sample strata, but those reporting a 

college degree ranged from 31 percent in the Boulder 

Creek-Santa Cruz-Watsonville area to 51 percent in the 

San Francisco-Oakland area. Ethnic composition varied 

substantially, with Santa Cruz respondents being almost 

exclusively white (89 percent), whereas 22 percent of San 

Francisco-Oakland respondents were black and an additional 20 percent identified themselves as being from other 

minority groups. 

Household composition and living arrangements varied 

significantly across the three sample strata. San FranciscoOakland respondents, compared with those in the other 

two sample strata, were least likely to be married (21 percent vs. 46-51 percent), most likely to live alone and without children, and had resided in California for an average 

of 25 years as contrasted with 30-32 years. 

Data on household income reflected information about 

household composition. The median household income of 

residents of San Francisco-Oakland was lower than that of 

residents of the other two areas, as were the number of 

persons contributing to household income and the number 

dependent on it. Hence, per-capita income within a household did not differ appreciably across the three sample 

strata. Residents of San Francisco-Oakland were least likely to own their residences (28 percent) and most likely to 

live in apartments or duplexes (65 percent). 

Possibly the most interesting difference across the three 

sample strata was respondents' differential reporting of experiences with prior earthquakes. Respondents were asked, 

'Prior to the October 17th earthquake, how many times 

had you experienced an earthquake?'San FranciscoOakland respondents reported experiencing an average of 

15 prior earthquakes, five-county respondents reported an 

average of 20, and Santa Cruz respondents reported an 

average of 28. Although the reports of San FranciscoOakland residents were consistent with their reports of living in California for the fewest years, the exceptionally 

high reports by Santa Cruz area residents were not easily 

explained by other information available in the data set or 

by known geological features of the area. It may be that 

Table 2.-Selected demographic characteristics by sample strata 

for earthquake (unweighted sample) 

[p = significance level in one-way analysis of variance] 

Area San Francisco/ Five countv Oaklancl Santa cru Pet. Pet. Pet. 

Pct. white** 69.4 Pct. female 56.1 Mean age 45.7 Pet. married* 51.0 Pct. college degree or more*' 39.0 Pct. employed fulltime 56.1 Mean socioeconomic index2 43.3 Per-capita income within household3 $15,000 Pct. own residence** 61.2 Mean years in California* 30.2 No. of prior earthquakes** 20.4 

Total n 451 83 122 

There were no significant differences between the sample strata in the number of years of schooling completed. 

Total Socioeconomic Index (TSEI) as determined by Stevens and Cho (1985). 

Significant differences exist between the strata in median household income, percent with incomes over $40,000, and the number contributing to and dependent on household income. 

Residents of San Francisco-Oakland reported lower household incomes, fewer persons contributing to the household income, and fewer persons dependent on the income. 

respondents in the Santa Cruz area were "telescoping" 

(misreporting or overreporting) by combining post-Loma 

Prieta aftershocks with pre-Loma Prieta earthquakes (see 

Aday, 1989; Bourque and Clark, 1992). 

DURING THE EARTHQUAKE 

Respondents were selected for inclusion in the study on 

the basis of where they lived at the time the sample was 

selected, but respondents were not necessarily in their 

homes or in the geographic area where their homes were 

located at the time of the earthquake. Consistent with their 

location at the time of the earthquake, persons in the Boulder Creek-Santa Cruz-Watsonville area were most likely 

(67.9 percent) to report that there was damage to major 

structures within five blocks of where they were. In contrast, 52 percent of San Francisco-Oakland respondents 

and 32.1 percent of the remaining respondents reported 

such damage (table 3). 

The majority (62 percent) of persons who were in the 

Santa Cruz area were at or in a private home at the time of 

the earthquake, while 50 percent of those in the five-county area and 42 percent of those in the San FranciscoOakland area were at a home (table 4). Approximately 25 

percent of respondents were at work or school, 15 percent 

were in transit, and 10 percent were in public places. Persons who were in public places were most likely (54.2 

percent) to report that there was damage to buildings 

around them, whereas those who were in a private home 
B 10 PUBLIC RESPONSE 

Table 3.-Respondents reporting damage within five blocks by 

sample strata where respondent was at the time of the earthquake 

(weighted sample) 

[Respondents exclude 23 persons who were out of the area at the time of the earthquake 13 persons who did not feel the 

earthquake, and 3 persons who did not know about damage in the area. p = significance level in chi-square analysis] 

Area San Francisco/ 

Any damage within pive county oaklana ' Santa Cruz 

five blocks? Pct. Pct. Pct. 

Yes 32.1 52.0 67.9 

No 67.9 48.0 32.1 

Total n 402 80 34 

p c 0.0001 

Table 4.-Type of place respondent was at the time of the earthquake by sample strata where respondent was at the time of the 

earthquake (weighted sample) 

[Respondents exclude 23 persons who were out of the area at the time of the earthquake. p = significance level in chi-square 

analysis] 

Location 

Area San Francisco/ 

Five county Oakland Santa Cruz Pet. Pet. Pet. 

Own or other's home 49.9 42.1 62.4 

Work or school 25.5 25.6 12.0 

In transit 15.7 15.6 11.1 

Public place or other location 8.9 16.7 14.6 

Total n 410 8 7 34 

were least likely (29.8 percent) to report such damage 

(p < 0.001). 

Whether a person was at home or elsewhere at the time 

of the earthquake did differ with demographic characteristics of respondents. As age increased, persons were more 

likely to be at home, with 76 percent of persons over 60 

being at home and only 34 percent of those under 32 

being at home. Consistent with the time of day and time 

of year, younger persons were most often at work or 

school. Married and formerly married persons were more 

likely (55 percent) to be at home than were never-married 

respondents (33.6 percent). Those with high incomes 

(>$62,500) and college degrees were more likely to be at 

home than were those with less income and less education. 

Respondents' reports of who they were with at the time 

of the earthquake differed with the geographic area where 

they were at the time of the earthquake (table 5). These 

differences reflected both reported differences in living arrangements across the sample and differences in respondents' locations at the time of the earthquake. Those who 

were in transit were most likely to report that they were 

Table 5.-Other people with respondent by sample strata where 

respondent was at the time of the earthquake (weighted sample) 

[Respondents exclude 23 persons who were out of the area at the time of the earthquake and 13 persons who did not feel the earthquake. p = significance level in chi-square analysis] 

Area San Francisco/ 

five county Oakland Santa Cru Pet. Pet. Pet. 

Alone 39.3 45.8 39.5 

Children <18 5.7 3.5 4.3 

Children and adults 7.7 2.3 15.2 

Other adult household members or relatives 16.5 5.9 23.8 

Co-workers 20.7 19.9 7.1 

Friends or neighbors 5.5 8.3 6.3 

Others 4.5 14.2 3.8 

Total n 403 82 34 

p = .0017 

alone (69 percent) (table 6). Those at work were most 

likely to report that they were with co-workers (72 percent). Those in private homes were about equally likely to 

report that they were alone (46 percent) or that they were 

with other household members, relatives, or children (45.8 

percent). It is recognized that, for those not at home at the 

time of the earthquake, responses may have been influenced by the respondents' perceived distance from home, 

need and desire to return home quickly, and ability to return home. Although it is possible with these data to calculate a crude estimate of the respondents' distance from 

home, it is not possible to ascertain respondents' knowledge of the whereabouts of loved ones, or other potential 

motivations for returning home. Respondents were asked 

about other household members only if they were with 

them at the time the earthquake occurred. 

RESPONSE BEHAVIOR DURING THE 

EARTHQUAKE 

The modal behavior at the time of the earthquake was to 

freeze in place or seek protection (72 percent) (table 7), 

but responses were modified by a respondent's location 

and companions at the time of the earthquake. Interestingly enough, responses did not change substantially with geographic location. Persons who were at work or school 

most often sought protection, whereas those in private 

homes were most likely to be with children and, consequently, to state that they went to a child. Forty-two percent of the 81 persons who said they were with children 

(either alone or with others) during the earthquake went to 

a child. 

Of greatest concern are the persons who said they ran 

during or, possibly, immediately after the earthquake. Run- 
HUMAN BEHAVIOR DURING AND IMMEDIATELY AFTER THE EARTHQUAKE Bll 

Table 6.-Other people with respondent by type of place where 

respondent was at the time of the earthquake (weighted sample) 

[Respondents exclude 23 persons who were out of the area at the time of the earthquake and 13 persons who did not feel the earthquake. p = significance level in chi-square analysis] 

Own or Public other's Work/ In place/ 

m imbS9.L Pet. Pet. 

Alone 46.0 19.4 68.8 23.7 

Children < 18 8.4 0.0 5.4 2.8 

Children and adults 12.6 0.0 2.7 6.1 

Other adult household members or relatives 24.8 1.5 5.6 15.7 

Co-workers 0.0 72.3 5.4 8.1 

Friends or neighbors 7.1 0.8 5.4 13.9 

Others 1.1 6.0 6.8 29.7 

Table 7.-Respondent's actions during the earthquake by type of 

place and sample strata where respondent was at the time of the 

earthquake (weighted sample) 

[Respondents exclude 23 persons who were out of the area at the time of the earthquake, 13 persons who did not feel the earthquake, and one person who could not remember the earthquake] 

tlQwS Yorkl;~&~oL Jn transit public dace Action Pct. Pct. Pct. 

Could not move Froze 

Froze, then sought 

protection 

Sought protection 

Ran outside Went to child Pulled car over 

Continued driving 

Other 

Five county 

Total n 2 04 104 60 3 5 

Total n 262 130 75 52 San FranciscoIOaklan~ 

ning was most often reported by people who were in the 

Santa Cruz area, where it was reported to occur almost 

regardless of the respondent's location at the time of the 

earthquake. In the other two areas, running was most frequently reported by persons who were in public places. 

Five of the persons who reported running were outside at 

the time of the earthquake. For these five persons, running 

was probably less dangerous than it might have been for 

the 50 persons who reported running while being inside a 

building at the time of the earthquake. Of the five persons 

who were outdoors and did run, one said he ran to escape 

boulders on Highway 17, another was jogging in the Marina at the time of the earthquake, while another reported 

running &Q her house during the earthquake! 

There were few differences in response behavior at the 

time of the earthquake by demographic characteristics. In 

general, women were more likely than men to freeze in 

place (33.4 percent vs. 24.8 percent) or to go to a child 

(9.6 percent vs. 4.3 percent). Older persons (over 41 

years) were also more likely to freeze in place (34.6 percent vs. 24.6 percent). During the Whittier Narrows earthquake, self-reported fright was associated with seeking 

cover and protection (Goltz and others, 1992). A similar 

association was seen in this data set for those respondents 

who were at work. 

RELATIONSHIP BETWEEN LOCATION, 

DEMOGRAPHIC CHARACTERISTICS, AND 

RESPONSE BEHAVIOR 

Where a person is at the time of an earthquake differs 

with the time of year, day of the week, and time of day 

that the earthquake occurs. For example, the distribution 

of persons across locations was quite different in the 

Could not move Froze 

Froze, then sought 

protection 

Sought protection 

Ran outside Went to child Pulled car over Continued driving 

Other 

Total n 37 2 1 11 13 

Santa Cruz 

Could not move Froze 

Froze, then sought 

protection 

Sought protection 

Ran outside 

Went to child Pulled car over Continued driving 

Other 

Total n 21 4 4 5 

Loma Prieta earthquake compared with the 1987 Whittier 

Narrows earthquake, with 67 percent of persons at home 

at the time of the early-morning Whittier Narrows earthquake. Although distributions of persons across locations 

will change, behavior within a given type of location may 

be constant across earthquakes. To examine these potential 

commonalities briefly, we assessed whether a person's behavior within a given location differed with the demographic characteristics of respondents. 

For those at a home, the tendency to stay in place during 

the earthquake was associated with increased age, being 

formerly married, and residing in California for between 

one and 20 years or between 31 and 87 years; the tendency to run outside was associated with being male. No associations were noted between respondent characteristics 

and the tendency to seek protection at a home. Respondents at work were more likely to remain in place if they 

were alone or with children. Workers were more likely to 

seek protection if they experienced high levels of fear during the earthquake. Respondents with higher levels of 

earthquake experience were more likely to stay in place 
PUBLIC RESPONSE 

only when low levels of fear were experienced. A positive 

level of perceived earthquake preparedness appeared to be 

associated with seeking protection via the experience of 

high levels of fear. Those more likely to run outside at 

work were male and had experienced low levels of fear 

during the earthquake. 

Respondents in public places were more likely to stay in 

place if they were white and in the company of adults 

only. Males were more likely to seek protection, and females were more likely to run outside in this situation. 

The tendency of respondents to stay in place in the presence of adults held only under conditions of high levels of 

fear. Further analyses revealed that gender differences in 

those who ran outside, regardless of location, held only 

when the respondents experienced high levels of fear during the earthquake and possessed college degrees. The underlying causes and implications of some of these 

associations are not immediately evident. Of those who 

were driving, respondents who were less than 32 or greater than 58 years old were the least likely to 

over and stop. 

EXPOSURE TO MEDIA 

The Loma Prieta earthquake was unusual 

pull the auto 

in that it occurred at the beginning of the broadcast of the first World 

Series game in the community where all the games were 

to be played. In fact, three of our respondents reported being at the Candlestick ballpark at the time of the earthquake. Although we have no way to check, we assume 

that because of the World Series more people than normal 

were already listening to radios or televisions when the 

earthquake occurred. Sixty percent of the sample had no 

broadcast media on at the time of the earthquake, whereas 

28 percent were watching television and 12 percent were 

listening to the radio. 

The number of people listening to radio and television 

did not differ with the geographic area where respondents 

were when the earthquake occurred nor with where their 

residence was located. Interestingly enough and in spite of 

the World Series game, it did not differ with gender. Females were as likely as males to have radios or televisions 

on. Exposure to radio or television at the time of the earthquake did differ with respondents' age, education and income, and the type of place in which they were. Persons 

with college degrees (64.4 percent) and those aged 32 to 

41 were least likely to have media on (67.2 percent), 

whereas those over 58 were most likely to be watching 

television (39 percent). A person's location at the time of 

the earthquake was associated with, and at least as important as, demographic characteristics in predicting exposure 

to media (table 8). When analyses were controlled for 

whether a respondent was at home or elsewhere, the associations observed between age and media exposure, and 

Table 8.-Exposure to media by type of place where respondent 

was at the time of the earthquake (weighted sample) 

[Respondents exclude 23 persons who were out of the area at the time of the earthquake, 13 persons who did not feel the earthquake, one person who could not remember the earthquake, and 7 persons missing for other reasons. p = significance level in 

chi-square analysis] 

Media on Public at time House Worklschool Jn transit l2hia of quake Pct. Pct. pet. Pct. 

Radio on 5.0 11.5 42.7 6.0 

Television on 50.3 7.0 4.1 5.8 

Nomediaon 44.7 81.6 53.2 88.3 

-- 

Total n 258 129 73 5 2 

education and media exposure, disappear. Persons who 

were at work or school were least likely to be using media 

(81.6 percent); those at home were most likely to be 

watching television (50.3 percent); and those in transit 

were most likely to be listening to the radio (42.7 percent). 

The earthquake disrupted respondents' listening status, 

and what happened next is of interest. Of the 242 persons 

who had radios or televisions on, 141 (58.3 percent) lost 

the broadcast at least temporarily because the electricity 

went out, and an additional 16 lost the broadcast for some 

other reason, including damage to the radio or television 

set. Of the 157 persons who lost the broadcast signal, 101 

(64.7 percent) sought another media source. Loss was associated with geographic location: 75 percent of those in 

the Santa Cruz area, 65.7 percent of those in the San Francisco-Oakland area, and 52.4 percent of those in the rest 

of the five counties lost the broadcast signal. 

Of the 305 persons who did not have broadcast media 

turned on, 64.4 percent attempted to turn on a radio or 

television (table 9). While the propensity to seek information did not differ by geographic location, the media used 

did differ, with those in the Santa Cmz area being more 

likely to resort to car radios and those in the San Francisco-Oakland area using portable battery-operated radios. 

Within the group that was not exposed to media, reported 

attempts to seek media did not differ with respondents' 

demographic characteristics but did differ with where they 

were; those at home sought information from television, 

and those at work sought information from radios. 

PASSIVE AND ACTIVE EXPOSURE TO BROADCAST MEDIA 

To summarize people's exposure to the broadcast media 

at the time of the earthquake, we categorized respondents 

into four groups according to how passive or active they 

were in seeking information from the media. The first 

group was the 184 persons (30 percent) who had no media 

turned on at the time of the earthquake and reported no 
HUMAN BEHAVIOR DURING AND IMMEDIATELY AFTER THE EARTHQUAKE B 13 

Table 9.-Media seeking by those who did not have media on at 

the time of the earthquake, by sample strata where respondent 

was at the time of the earthquake (weighted sample) 

[Respondents exclude 250 persons who had media on during the earthquake, 23 persons who were out of the area at the time of the earthquake, and 13 persons who did not feel the earthquake. p = significance level in chi-square analysis] 

Action 

Area San Francisco/ Five county Qakbnd Santa Cru PCt. Pet. Pet. 

Turned on TV 

Tried TV 

Used battery TV 

Turned on radio 

Tried radio 

Used battery radio 

Used car radio 

Did nothing 

Total n with media off at time of quake 234 51 20 

efforts to gain access to radio or television. These were the 

"nonconsumers." The second group was the 85 persons 

(13.9 percent) who had a radio or television on that did 

not go off. These persons might be considered "passive 

consumers" of information provided about the earthquake. 

The third group was the 105 persons (17.2 percent) who 

were tuned into the media, lost contact because of power 

outages or other events, and actively sought another station or source. Some proportion of these persons must be 

assumed to have been more interested in the World Series 

than in the earthquake. The last group, the "active seekers," were the 238 persons (38.9 percent) who were not 

tuned into media and then sought media. 

When analyses were re-run using this summary variable, 

the findings reported above generally were replicated. 

Table 10 summarizes how media-seeking behavior differed 

with geographic location and type of place. Persons who 

were in public places were most likely not to be tuned into 

media at the time of the earthquake and were most likely 

to seek information after the earthquake occurred, regardless of the geographic area where they were located. There 

were no particular differences with demographic characteristics of respondents beyond those already noted. However, knowing & a person was with in addition to where 

they were provided some additional information about 

those who were not at home when the earthquake occurred 

(table 11). Persons who were at home alone or with children were least likely to be exposed to media either during 

or after the earthquake, whereas those who were with other adults outside the home were most likely to seek media 

after the earthquake. 

Level of fear at the time of the earthquake also appears 

to have a mild curvilinear relationship with media expoTable 10.-Media seeking following the earthquake by type of 

place and sample strata where respondent was at the time of the 

earthquake (weighted sample) 

[Respondents exclude 23 persons who were out of the area at the time of the earthquake, 13 persons who did not feel the earthquake, and 7 persons missing for other reasons. p = significance level in chi-square analysis] 

Public &!&,g Worklschoo~ In transit Pet. Pet. Pct . 3 

Five county (p < 0.001) 

No media seeking 27.4 38.2 24.2 23.1 

Media on & stayed on 22.0 4.8 25.8 9.1 

Media on, went off, & sought new media 23.6 7.0 10.6 2.9 

No media on; sought media 27.0 50.0 39.4 64.9 

Total n 200 103 5 8 35 

Northeast San Francisco and Oakland (p < 0.05) 

No media seeking 31.6 39.2 0.0 38.4 

Media on & stayed on 8.1 8.6 36.6 7.6 

Media on, went off, & sought new media 31.5 4.5 18.3 0.0 

No media on; sought media 28.9 47.7 45.1 54.0 

Total n 37 22 11 13 

Boulder Creek-Santa Cruz-Watsonville. (p = nonsignificant) 

No media seeking 31.2 23.8 17.8 33.3 

Media on & stayed on 3.1 0.0 36.7 0.0 

Media on, went off, & sought new media 40.2 11.9 4.4 0.0 

No media on; sought media 25.6 64.4 41.1 66.7 

Total n 2 1 4 4 5 

Table 1 1 .-Media seeking behavior by who respondent was with 

and whether or not at home at the time of the earthquake 

(weighted sample) 

[Respondents exclude 23 persons who were out of the area at the time of the earthquake, 13 persons who did not feel the earthquake, and 7 persons missing for other reasons. p = significance level in chi-square analysis] 

Response 

Alone or with 

J.+ children With adults Pet. Pet. 

Respondent Was at Home (p < 0.05) 

No media seeking 35.0 

Media on & stayed on 15.1 

Media on, off, & sought new media 23.1 

No media on; sought media 26.8 

Total n 141 117 

Besoondent Was Not at Home (p < 0.015) 

No media seeking 29.2 

Media on & stayed on 20.8 

Media on, off, & sought new media 7.9 

No media on; sought media 42.1 

Total n 92 161 

sure (table 12). Those who were moderately frightened or 

who enjoyed the earthquake reported somewhat more 

media-seeking than did those who were very frightened. 

Persons who were not at all frightened by the earthquake 

were least likely to seek media information actively. 
PUBLIC RESPONSE 

Table 12.-Media seeking behavior by how afraid respondent was at the time of the 

earthquake (weighted sample) 

[Respondents exclude 23 persons who were out of the area at the time of the earthquake, 13 

persons who did not feel the earthquake, and 7 persons missing for other reasons. p = significance level in chi-square analysis] 

Very Somewhat Not very Not at all Enjoyed 

frightened frightened frightened frightened experience Response Pct. Pct. Pct. Pct. Pct. 

No media seeking 33.3 22.5 28.9 41.4 29.4 

Media on & stayed on 10.4 17.5 15.5 22.1 14.0 

Media on, went off, & sought new media 19.2 18.0 13.2 12.8 13.5 

No media on; sought media 37.2 42.1 42.3 23.7 43.1 

Total n 155 179 9 2 6 4 22 

UTILITIES 

Loss of utilities clearly was associated with proximity of 

a respondent's home to the epicenter or to an area that 

experienced substantial shaking. Only 2.6 percent of the 

respondents in the Boulder Creek-Santa Cruz-Watsonville 

area and 8.0 percent in the San Francisco-Oakland area 

reported that none of their utilities went out (table 13). 

Electricity was most commonly lost, and if a single utility 

was lost, it was almost always electricity. Hardly anyone 

lost only gas, telephone, or water. The most common combination of utilities lost was electricity and telephone. In 

the Santa Cruz area, 53.9 percent of the respondents lost 

two or more utilities, with electricity always being one of 

the utilities reported lost. In contrast, 23.4 percent of the 

five-county residents and 33.4 percent of Oakland area 

residents lost two or more utilities. 

Reported losses of utilities did not differ with any of the 

standard demographic characteristics. 

DAMAGE TO HOMES AND PERSONAL 

PROPERTY 

Reports of damage varied with distance from the epicenter (table 14). Fifty percent of the residents in the Boulder 

Creek-Santa Cruz-Watsonville area reported damage to 

their homes, whereas only 22 percent of Oakland area respondents and 17 percent of those in the rest of the area 

reported damage to their homes. Between 12 percent and 

17 percent reported damage to personal property only. The 

most common structural damage occurred to walls, ceilings, or floors, with persons in the Santa Cruz area reporting the most severe damage. As would be expected, 85 

percent of those who reported damage to their homes also 

reported the loss of one or more utilities, whereas 73 percent of those without residential damage reported loss of 

utilities. 

Table 13.-Respondents who experienced loss of one or more 

utilities by sample strata (unweighted sample) 

[p == significance level in chi-square analysis] 

Utility 

Area San Francisco/ Five county 

Pet. Santa Cruz 

Pet. 

None went out 

Electricity only 

Gas only 

Phone only 

Electricity & phone 

Phone & gas 

Water & electricity 

Electricity & gas 

Water & gas 

Phone, electricity, & gas 

Phone, -water, & electricity 

Water, electricity, & gas 

Phone, electricity, water, & gas 

Total n 451 83 122 

p < 0.001 

Consistent with the proportion of respondents who reported damage and the kind of damage reported, residents 

of the Santa Cruz area reported the highest average 

amount of damage at $19,940 and two persons reported 

damage of more than $100,000. Persons in Oakland and 

San Francisco reported an average of $7,333 in damage, 

whereas those in the five-county area reported an average 

of only $2,431 in damage. In contrast to other studies, the 

type and dollar amount of damage reported did not differ 

with the respondent's demographic characteristics (Bolin 

and Bolton, 1986; Bolin and Stanford, 1991; Tierney, 
HUMAN BEHAVIOR DURING AND IMMEDIATELY AFTER THE EARTHQUAKE 

Table 14.-Damage at respondent's home by sample strata (unweighted sample) 

[p = significance level in one-way analysis of variance] 

Area San Francisco/ 

five county Damage Pct. Pct . Pct . Qakhnd~ 

No damage 67.8 66.3 33.6 

Personal property only 15.3 12.0 17.2 

Driveway 0.7 0.0 0.0 

Chimney/patio/porch 0.4 1.2 6.6 

Water heater 0.4 1.2 0.8 

Damage to any 1 of: wall/ceiling/floor 7.5 10.8 6.6 

Damage to any 2 of: wall/ceiling/floor 2.4 3.6 13.9 

Foundation 1.6 2.4 4.9 

Pool/water tank 0.7 0.0 2.5 

Gas lines broken 0.4 0.0 1.6 

Water pipes broken 2.0 1.2 6.6 

Collapse of any 2 of: wall/ceiling/floor 0.2 0.0 1.6 

Building off foundation 0.4 1.2 1.6 

Entire building 0.0 0.0 2.5 

Mean dollar amount of damage for those who reported 

damage* $2,431 $7,333 $19,940 

Total n 451 83 122 

* p < 0.001 

1985). This may result, however, from characteristics of 

our sample (see "Sample Limitations"). 

EVACUATION BEHAVIOR 

As would be expected, evacuation varied with proximity 

to the epicenter and the amount of damage to a respondent's home, but damage to houses and utilities was not 

the sole precipitator of evacuation. For example, 55 percent of those in the Santa Cruz area who reported damage 

to their homes did not evacuate, whereas 15 percent of 

those in other areas who reported no damage did evacuate. 

Forty-three percent of Santa Cruz-area respondents evacuated, and 36.5 percent of those evacuated because an official recommended it or because the condition of their 

homes necessitated evacuation (table 15). In the other two 

areas, less than 20 percent of the respondents reported 

evacuating, and more than 50 percent evacuated because 

of being upset or for other reasons. Persons in the San 

Francisco and five-county areas also were more likely than 

residents of the Santa Cruz area to cite the loss of electricity alone as a reason for evacuating. 

BOULDER CREEK-SANTA CRUZ-WATSONVILLE 

Decisions to evacuate differed with geographic location. 

Evacuation in the Boulder Creek-Santa Cruz-Watsonville 

Table 15.-Reason for evacuating by sample strata for earthquake (unweighted sample) 

[Respondents exclude one deviant case: a woman who left the Santa Cruz area after the earthquake and never returned to her apartment. p = significance level in one-way analysis of variance or chi-square where appropriate] 

Area San Francisco/ Five county Oaklana Santa Cruz 

(n = 451) (n = 83) (n = 122) PCt. Pet. Pet. 

Pct, who evacuated* 17.5 

Total n 451 

Those Who Evacuated: 

Mean number of hours 41.9 evacuated* 

Reason for evacuation* Official or condition of structure required it 11.4 

2 or more utilities off 8.9 Gas off 2.5 Electricity off 22.8 Road out 1.3 States upset only 24.1 Other reasons including invitation from friend 

or relative, afraid of further damage, prediction of aftershocks, and to make contact with others 29.1 

area was largely motivated by damage to homes and utilities. There was also some greater tendency for younger 

persons (less than 40 years) to evacuate. 

FIVE-COUNTY AREA 

In contrast, in the five-county area, decisions to evacuate 

varied with demographic characteristics of respondents, 

who they were with at the time of the earthquake, and the 

amount of fear they said they experienced at the time of 

the earthquake. Women were more likely than men to 

leave their homes (21 percent vs. 13 percent), and persons 

under 40 years of age were more than twice as likely to 

evacuate as those over 40 (24 percent vs. 10.6 percent). 

This same group (persons under 40) contributed to the 

finding that persons who had lived in California for between 20 and 40 years were more likely to evacuate after 

the earthquake than were those who had lived in California either fewer than 20 or more than 40 years. 

Forty percent of the 58 persons in the five-county area 

who reported being with children at the time of the earthquake reported evacuating after the earthquake. Only 10 

of these persons evacuated because of structural damage, 

advice of officials, or loss of utilities. The remainder evacuated because of fear, a need to make contact with other 

persons, invitations from friends or relatives, or concern 

about aftershocks or further damage. The contrast between 

the group with children and those who were alone is 
PUBLIC RESPONSE 

Table 16.-Percent evacuated and reason for evacuation by sample strata for 

earthquake and level of fear (unweighted sample) 

[p = significance level in chi-square analysis] 

Reason for evacuation 

San Francisco/ Five county Oakland Santa Cruz Very or very or Very or somewhat Not somewhat Not somewhat Not fearful fearful fearful fearful fearful fearful Pet. Pet. Pet. Pet. Pet. Pet. 

Did not evacuate 77.8 90.8 78.2 92.9 54.5 64.7 

Psychological reasons1 11.1 6.1 12.7 3.6 10.2 11.8 

Structure or utilities only2 2.1 1.2 1.8 0.0 5.7 5.9 

Both 9.0 1.8 7.3 3.6 29.5 17.6 

Total n 288 163 5 5 28 8 8 3 4 

P = <.01 .39 .61 

' Includes either alone or in combination: evacuation because too upset to stay, afraid of further damage, concerned about aftershocks, invitation from a friend, or to make contact with others. 

Includes either alone or in combination: evacuation because of structural damage, utilities out, an official advised evacuation, or the road was out. 

particularly striking. While 40 percent of those in the fivecounty area who were with children evacuated, only 16.5 

percent of those who were alone and 14 percent of those 

who were with other adults decided to evacuate. Like 

those with children, however, only 43 percent of those 

who were alone (12 of 28 vs. 10 of 23) evacuated because 

of major structural or utilities problems. Thus, a substantial proportion of evacuations that occurred outside the 

most damaged areas probably were not motivated by 

threats to physical safety. 

Evacuation behavior in the five-county area probably 

was motivated in part by fear (table 16). Persons who said 

they were very fearful or somewhat fearful at the time of 

the earthquake were somewhat more likely to evacuate, 

even when structures and utilities did not necessitate evacuation. While this occurred to some extent regardless of 

geographic location, it was most pronounced in the fivecounty area, possibly because persons in the Santa Cruz 

area, at least, had fewer options regarding where they 

could go if they decided to leave their homes. 

SAN FRANCISCO-OAKLAND 

In the San Francisco-Oakland area, loss of electricity 

was one reason given for evacuating. Evacuation was predicted by experiencing few prior earthquakes. Twenty-five 

percent of persons who reported feeling 10 or fewer prior 

earthquakes evacuated, in contrast to only 3.3 percent of 

those who had experienced more than 10 earthquakes. 

Evacuation was also precipitated by fear, but the numbers 

were too small to reach significance. Numbers also were 

too small to examine in detail how the presence of children affected the evacuation behavior of San FranciscoOakland residents. Only four persons were with children 

at the time of the earthquake. One of those four evacuated 

and cited damage to structures and utilities as well as upsetness as the reason for the evacuation. 

MARITAL STATUS AND SOCIOECONOMIC STATUS 

Marital status and socioeconomic status, as measured by 

household income and completion of a college education, 

were not associated with evacuation behavior in any of the 

three geographic areas. 

BEHAVIOR WHILE EVACUATED 

Once respondents left their households, persons in San 

Francisco-Oakland and the five-county area stayed out of 

their houses for an average of 2 days. Those in the Santa 

Cruz area stayed out for an average of 7 days. Respondents 

who evacuated because of structural damage, advice from 

officials, or absence of utilities were asked a series of questions about their evacuation experiences. Most respondents 

in this group said that the decision to evacuate was theirs or 

resulted from a combination of factors (table 17). Evacuees 

were about evenly divided between staying with friends or 

relatives and staying outside, with those in the Santa Cruz 

area most frequently staying outdoors in tents or recreational vehicles. Most persons took only their clothing. Of particular interest is the tendency not to take valuables and 

documents. The decision to leave documents and valuables 

behind probably resulted from three things: a feeling that 

the evacuation was of short duration (at least for those who 

evacuated because utilities were out), an inability to reach 
HUMAN BEHAVIOR DURING AND IMMEDIATELY AFTER THE EARTHQUAKE B17 

Table 17.-Characteristics of evacuation by sample strata for 

earthquake (unweighted sample) 

[Only respondents who reported evacuating because of structural damage, advice from officials, or absence of utilities were asked this series of questions] 

Area San Francisco/ Evacuation Five county 3anta Cruz characteristics Pct. Pct. Pct: 

mat finally convinced those who did not leave to evacuate? 

Officials/bldg mgr 5.0 0.0 7.7 

Self only 77.5 33.3 71.8 

Friends 2.5 0.0 7.7 

Absence of utilities 5.0 16.7 0.0 

Roads out 2.5 0.0 0.0 

Combinations 7.5 50.0 12.8 

Where did you stav? 

Relative 22.5 33.3 15.4 

Friend 22.5 50.0 23.1 

RV or van 2.5 16.7 15.4 

Car or truck 12.5 0.0 2.6 

Outside 35.0 0.0 41.0 

MotelIApartment 5.0 0.0 2.6 

What did vou take with vou? 

FamilyISelf only 45.0 0.0 33.3 

Clothing only 25.0 50.0 28.2 

Supplies only 12.5 0.0 7.7 

Valuables only 2.5 0.0 2.6 

Pets only 5.0 0.0 2.6 

Clothing & supplies 0.0 16.7 12. 8 

Valuables, documents 

and other things 10.0 33.3 12.8 

Pct. who returned home while evacuated 47.5 83.3 79.5 

Total n 40 6 39 

valuables, when houses were substantially destroyed, and 

the distance traveled by those staying outside, who usually 

stayed in their own yard or a nearby area. 

DISCUSSION 

We are concerned with the implications of our findings 

for policy, practice, and future research, given the following: (1) Our respondents were at work or school, at home, 

in a store or other public location, or in transit. (2) Older 

persons were more likely to be at home, whereas nevermarried younger persons were equally likely to be at 

work, in transit, or at home. (3) Those who were in the 

Santa Cruz area were more likely to be at home, a fact 

which probably reflects their greater propensity to live in 

larger households that contain children; it may also reflect 

closer proximity between workplace and residence for 

many residents of the Santa Cruz area. 

RESPONSE BEHAVIOR 

Where a person was at the time of the earthquake largely 

determined who they were with and what they did during 

and immediately after the earthquake. In contrast to the 

1971 San Fernando and 1987 Whittier Narrows earthquakes, which occurred in the early morning, for the early 

evening Loma Prieta earthquake, a substantial number of 

our respondents were not at home. Others have speculated 

that irrational behavior and activity detrimental to effective 

response by authorities increases when those in a disaster 

are separated from loved ones and property. In looking at 

what people do during an earthquake, we were interested in 

finding out whether their actions increased or decreased the 

risk of injury to themselves and others. Although disaster 

researchers have repeatedly demonstrated that people do 

not exhibit panic behavior or mass hysteria during an earthquake or other disaster, policymakers and practitioners continue to express concern that they will. At the same time, it 

is certainly true that programs encouraging people to think 

in advance about what they would do if a disaster occurs 

can reduce fear of the unknown and increase the range of 

safe alternatives available to an individual. 

As expected, we saw little evidence that our respondents 

panicked at the time of the earthquake. Most persons made 

an active response that was designed to get them to a 

more protected location in a safe manner, or simply stayed 

where they were, which, in some cases at least, is preferable to making a move that increases risk of danger to self 

or others. The propensity to do the "right thing" differed, 

however, with the geographic area where a person was, 

the type of place, and the person's companions. 

Possibly reflecting the success of worksite earthquakepreparedness programs and the beneficial effect of being 

with peers who have been exposed to the same information, persons who were at work or school were the most 

likely to take active measures to protect themselves. Furthermore, the propensity to seek protection increased with 

proximity to areas that experienced severe shaking. Even 

when workers did not seek protection immediately, many 

sought it before the shaking stopped, and the majority of 

the remainder froze in place, which, while not decreasing 

their risk of injury, also did not increase it. Respondents 

who were at home or in a public place were substantially 

less likely to actively seek protection, at least as the earthquake started. As it continued, some moved to a protected 

location, and others went to children. 

The most problematic response that our respondents 

made was to run during or immediately after the earthquake. Running in such a situation may indicate a panic 

response and certainly is unwise. While none of our respondents reported being injured as a result of running, 

running clearly increases the risk that a person will be 

thrown against objects or buildings, or that objects or parts 

of buildings will fall on them as they run past. In an attempt to better understand this small but important group, 

we examined what, if anything, differentiated "runners" 

from "non-runners" within each location where running 

occurred. 

Fifty-five people reported running during the earthquake: 

14 were at work, 27 were at home, and 14 were in a pub- 
B18 PUBLIC RESPONSE 

lie location. Those who ran at work were younger (12 of 

14 were less than 42 years old) and primarily male (1 1 of 

14), with substantial incomes but without college degrees. 

All but one were with other adults at the time of the earthquake, which may suggest that some level of crowd behavior or mass hysteria occurred. However, runners did 

not indicate a higher level of fear at the time of the earthquake, which would be consistent with a panic reaction. 

To the extent that respondents commented on their behavior, little overt evidence of panic on the part of the respondent or others was provided. A typical comment was to 

say "I ran for the door." In other words, the objective (a 

door frame) was a worthy one, but the method of getting 

there left a great deal to be desired. 

Interestingly enough, those who reported running at 

home were also more likely to be younger males (17 of 

27) who disproportionately reported themselves as never 

married but did not differ from nonrunners in socioeconomic status. All were alone (n=17) or with other adults 

@=lo). Comments by this group resembled those made by 

the group that was at work, but one young man said, "I 

dove out the window and ran for open space." The only 

place where female runners outnumbered male runners 

was in public places (11 of 14 were women). Here, also, 

one respondent specifically mentioned concern about her 

children as the factor that motivated her running, saying, 

"I wanted to get to my car and get home because my children were with a babysitter." 

Our findings on response behavior have at least three 

implications for policy and practice. First, younger men 

either have been ignored as a target of disaster-training information or, alternatively, have rejected such information 

as unnecessary or irrelevant to their concerns. These data 

suggest that future efforts should consider how to engage 

the attention of this group. Second, our findings suggest 

that disaster-preparedness plans and drills in work sites 

generally have been successful. Persons who were at work 

reacted actively and appropriately. Although worksite efforts should be continued, these findings suggest that more 

programs should assist people in learning what to do in 

private homes and, even more particularly, in public places. Homes and public locations present different kinds of 

challenges to practitioners. Public locations are particularly problematic, since every public place is different and 

any one individual spends very little time at widely spaced 

intervals at a given public location. Procedures need to be 

developed that allow persons to identify and act on "generic" information about locations which can then be generalized from one location to another. In particular, people 

need to know how to scan and quickly assess a location 

for safety, and how to behave in the presence of large 

numbers of other people so that they do not endanger 

themselves or others. 

While public locations are problematic because of their 

wide diversity, homes are problematic because of their 

overwhelming familiarity. To the extent that humans perceive homes as a sanctuary, they probably fail to realize 

that houses and the furniture, dishes, pictures, and other 

objects we put in them can become lethal weapons in a 

severe earthquake. Typically, work sites bolt file cabinets, 

conduct earthquake drills, have contingency plans for 

emergencies, and store water and first aid kits on site, but 

many of the workers never consider taking similar precautions at home. As a result, we saw many more of those 

who were at home simply freezing in place rather than 

actively seeking shelter. There are times, of course, when 

freezing in place may be the behavior of choice. Certainly 

one is better off staying seated in an overstuffed chair than 

heading for a door frame, only to get there and have the 

door slam into one with the force of the earthquake. We 

doubt, however, that the people who told us they froze in 

place in this earthquake settled on that behavior because 

they had systematically considered what they should do in 

the past or because they rapidly assessed their options at 

the time of the earthquake and concluded that this was the 

safest alternative. We need to know more about what 

"freezing in place" means and the circumstances under 

which it is the behavior of choice. We also need to encourage people to do more to "earthquake-proof' their homes, 

so that decisions to stay in place do not result in having 

objects or buildings pile on top of one. 

Finally, we need to examine in some detail what it 

means to "go to a child" at the time of an earthquake. As 

the comment demonstrates, in their concern for a child's 

physical or emotional safety, parents or guardians may 

place themselves at significant risk. Adults might be better 

advised to call instructions to children and stay where they 

are, rather than moving through potentially lethal obstacles 

to a child who is relatively safe in a crib or play pen. In 

the case where a woman ran out of a store, had she broken 

her leg as a result of running she would have been of little 

use to her children or the babysitter. She should have taken a little more time to consider her alternatives and move 

safely. 

USE OF MEDIA 

In the literature review, we pointed out that the mass 

media has been blamed for spreading false, incomplete, or 

incorrect information about earthquakes, in general as well 

as when they occur, while simultaneously being viewed as 

almost godlike in its potential impact on individuals and 

populations. Whether right or wrong, all these scenarios 

assume that individuals and groups turn to the media as 

their first, best, and undisputed source of information 

about what to do in preparation for disasters, what has 

happened in a disaster, and what they should do after a 

disaster. The recommendation that people should invest in 

battery-operated radios for use during and after a disaster 
HUMAN BEHAVIOR DURING AND IMMEDIATELY AFTER THE EARTHQUAKE B19 

reflects, in part, this deification of the power and value of 

mass media. In fact, how valuable are radio and television 

in the aftermath of an earthquake? 

We did not collect data that allowed us to describe the 

content of media coverage, evaluate its adequacy, or assess 

the extent to which our respondents used information 

transmitted by the media. As reported above, we do know 

whether respondents attempted to use the media. We also 

know what they considered their best source of information on the day of the earthquake and afterward, and 

whether respondents owned battery radios at the time of 

the earthquake. Clearly, if people do not turn on a television or radio, they cannot progress to the second step of 

listening to it, or the third step of utilizing and evaluating 

any of the information provided. 

Because of the World Series, we assumed that more people than normal had either radios or television sets turned 

on when the earthquake occurred on October 17. Forty percent of our sample did indeed have either a radio or television set on. This group tended to be at home at the time of 

the earthquake and, consistent with being at home, tended 

to be older and less well educated. When the earthquake 

occurred, an additional 30 percent of our respondents attempted to turn on a radio or television set. Contrary to 

other research that would predict that persons of higher 

socioeconomic status would be more likely to seek information, information-seeking did not differ with demographic characteristics of respondents. Consistent with 

media dependency theory and behavior following the 

Mount St. Helens eruption, the need for information appears to have existed for everyone in our sample regardless 

of factors which normally predispose an individual to seek 

information (for example, Hirschburg and others, 1986). 

Media-seeking did differ with who a person was with and 

where they were. It is particularly interesting to note that 

those who were alone or with children-the two groups one 

might hypothesize would be in greatest need of information-were least likely to seek it. This was in spite of being 

in private homes which were the most conducive location 

for obtaining access to a radio or television. 

It is also interesting to note that those who were already 

tuned in to radio or television and those who were not 

tuned in did not differ in their propensity to remain tuned 

in or to seek access. Sixty-four percent of those who were 

tuned in and lost their signal and 64 percent of those who 

were not tuned in at the time of the earthquake sought 

information from either radio or television. This suggests 

that a substantial proportion of the population does consider radio and television an important source of information 

during an emergency. Seventy percent of our total sample 

(n=472) had access to the media either at the time of the 

earthquake or immediately after it occurred. Eighty percent of this group (n=387) actively sought access. 

This information, in combination with other information 

available in this data set, suggests that persons who are 

already "tuned into" the media, either in the sense that 

they use it for entertainment or see it as a source of important information, are the ones that turn to it in a disaster 

situation. For example, it is interesting to examine the behavior of the 70 percent of this sample who said they already had a battery-operated radio at the time of the 

earthquake, since ownership of a battery-operated radio 

can indicate both valuation of media and acceptance of 

principles espoused in disaster preparedness. Those with 

battery-operated radios were more likely to have a radio or 

television on when the earthquake occurred and, if not, 

were also more likely to try to tune in radio or television 

after the earthquake. Seventy-four of the 244 persons who 

owned a battery-operated radio but who did not have either radio or television on when the earthquake occurred 

specifically used a battery-operated radio, whereas an additional 43 used a car radio after the earthquake occurred; 

30 percent made no effort to turn on media. Of the 125 

persons who neither had a battery-operated radio at the 

time of the earthquake nor purchased one afterwards, 36 

percent (n=45) made no effort to obtain information from 

the media. 

At the time of the interview, respondents were asked 

what their best source of information was on the day of 

the earthquake. Although 30 percent (n=184) of the sample did not turn on a radio or television at the time of the 

earthquake, many of them (n=156) still cited radio or television as their best source of information on October 17. 

Many of these people undoubtedly turned on radios or 

television sets later in the evening, but we suggest that 

others accessed the media indirectly through friends and 

relatives. Thus, even for those persons for whom media 

were not a source of immediate information, broadcasters 

had the potential of influencing what residents of the Bay 

Area did and when they did it. Only 8 percent of our respondents cited a "best" source of information other than 

radio or television on the day of the earthquake. Some of 

these persons had access to emergency communications 

either because they were emergency personnel or because 

they had access to groups such as police or other emergency personnel. Radio was cited as usually the best source of 

information by those in San Francisco-Oakland (63 percent) and Santa Cruz (67 percent), whereas television was 

cited by those in the rest of the five-county area (52 percent). In the days following the earthquake, television became the primary source of information for everyone 

regardless of area (59.5 percent), newspapers became the 

second important source (21.6 percent), and radio was cited as important by 14 percent of the sample. 

Clearly our findings suggest that radio and television 

have the potential to be a major source of information before, during, and after an earthquake. At 5:00 p.m. on a 

weekday a substantial plurality of the population apparently has a radio or television on, regardless of where they 

are. In the event of an earthquake or other extraordinary 
B20 PUBLIC RESPONSE 

event, a sizable additional group seeks information from 

the media. Still others obtain information as time passes. 

Even those who do not actively seek information, at least 

immediately, cite radio and television as a major, important source of information. The task, then, for practitioners 

and policymakers is to determine how media might most 

productively be used in earthquake preparedness, response, and recovery, and how the media might be recruited to the task. 

EVACUATION 

We usually think of evacuation as being a behavior that 

occurs when damage to buildings or utilities is severe 

enough to pose a threat to the physical safety of inhabitants. Indeed, past research has focused on ensuring that 

people respond to warnings when danger is imminent. 

This data set suggested, however, that evacuation also occurs in response to other concerns and that evacuation 

sometimes may be unnecessary, dysfunctional, or even 

counterproductive to the goals of disaster response institutions. Although a majority of our respondents, regardless 

of geographic area, experienced loss of one or more utilities, and substantial numbers experienced some damage to 

their homes, evacuation behavior only partially reflected 

these disruptions. Three groups of evacuees or potential 

evacuees of interest to policymakers and practitioners can 

be identified in these findings: those who evacuated because of substantial loss of utilities or structural damage, 

those who experienced problems comparable to many in 

group one but who chose to remain in their homes, and 

those who evacuated despite reporting no overt property 

damage sufficient to cause evacuation. 

The first group, those who evacuated because of damage 

to property or utilities, is the group that we would expect 

to find dislocated in the aftermath of an earthquake. Although some may overstate damage in order to justify 

their decision to leave, most are, after all, the group that 

disaster workers are trained to deal with. This is the group 

for whom we expect to provide services. 

Less is known about the second group, but they are of 

interest for a couple of reasons. First, what is it about their 

circumstances that allows them to remain in their homes? 

Do they have no alternative? Or, do they ignore real dangers to self and others in an effort to protect property or to 

deny the extraordinary nature of the event? These preliminary findings suggest that in the Boulder Creek-Santa 

Cruz-Watsonville area, many respondents may have stayed 

in their homes because they had no alternative. For example, although the amount of damage reported by respondents in Santa Cruz suggests that as many as 30 persons 

might have evacuated because of structural damage to 

their homes, only 19 persons actually evacuated for such 

reasons. Similarly, more than half the Santa Cruz respondents reported having two or more utilities out, yet only 

nine persons reported evacuating for that reason. Thus, it 

is possible that some respondents simply had no alternative and had to stay in their homes. Other possible explanations are that, even when alternatives existed, 

respondents stayed in their homes either because of concerns about their property or because they denied the extent of the damage. Finally, there is the possibility that 

some subset of persons who evacuate-even when structural damage or utilities are cited as the reason-do so 

when it really is not necessary. Evidence in support of this 

last possibility comes from a number of sources, including 

our third group. 

Although close to half of the sample, regardless of geographic area, said that their electricity went out, very few 

respondents found it necessary to evacuate when only 

their electricity was out. Yet, even in Santa Cruz, where 

we have suggested that alternative locations for evacuees 

may have been limited, seven persons stated that they left 

their homes only because their electricity went out. 

Whether evacuation under such circumstances represents 

an overreaction on the part of this group or simple prudence remains for further analysis. 

While substantial numbers of reported evacuations in the 

Santa Cruz area occurred because of at least superficial 

evidence of damage to structures or utilities, most of the 

evacuations reported by the rest of the sample occurred 

because the respondents were upset. Of interest is what 

this means for practitioners and policymakers. On the one 

hand, as long as persons who evacuate for such reasons 

stay out of the way of officials who need access to roads, 

telephones, and other facilities in order to insure prompt 

response to groups that need it, we could argue that such 

evacuations are of no concern to officials. On the other 

hand, the evacuation behavior of such individuals may be 

masking other kinds of problems that will ultimately become the concern of officials. For example, in our study 

after the 1987 Whittier Narrows earthquake, only 20 persons reported evacuating (Bourque and others, 1991). 

Nineteen of those persons said that they left their homes 

only because they were upset. At the time of the Whittier 

Narrows interviews, this group of evacuees was significantly more psychologically distressed, as measured using 

a standard measure of psychological symptomatology, than 

were those who did not evacuate. Thus, the decision to 

evacuate and the reason for evacuation may be an important signal in targeting those at risk of psychological distress following a disaster. The data reported here suggest 

that there are two different groups of evacuees. The first 

group evacuate because of earthquake-induced events that 

make it difficult for them to stay in their homes: structural 

damage, absence of utilities, and the advice of officials. 

The second group evacuates because of (possibly pre-existing) psychological distress. It is quite clear that persons' 

reports that they "evacuated" cannot be straightforwardly 
HUMAN BEHAVIOR DURING AND IMMEDIATELY AFTER THE EARTHQUAKE B21 

accepted to mean that damage to homes or to utilities necessitated that they leave their homes for personal safety. 

SUMMARY 

Telephone interviews were conducted with 656 residents of five counties in the San Francisco Bay Area an 

average of 224 days after the Loma Prieta earthquake. 

Analyses examined where respondents were, who they 

were with, what they did at the time of the earthquake, 

their exposure to radio and television during and immediately after the earthquake, loss of utilities, damage to 

homes and personal property, and evacuation behavior 

following the earthquake. Respondents' reports of what 

they did at the time of the earthquake differed with 

whether they were in a private home. Most persons reported seeking protection, freezing in place, or other 

adaptive behaviors. At the time of the earthquake, 40 percent of respondents had radios or televisions turned on. 

An additipnal 30 percent sought information from the media after the earthquake occurred. Attempts and the ability 

to obtain access to media differed with whether persons 

were at home or elsewhere and with their proximity to 

the epicenter. Persons in the Santa Cruz and Oakland areas were most likely to use battery radios or car radios on 

the day of the earthquake and to report that radios were 

their best source of information. 

Reports of damage to homes, personal property, and utilities varied with proximity to the epicenter, with those in 

the Santa Cruz area being most likely to report disruptions. Loss of utilities or structural damage did not necessarily result in evacuation. Many fewer persons evacuated 

than reported damage, and of those who evacuated, many 

left their homes because they were upset. 

ACKNOWLEDGMENTS 

Data collection for this project was supported by the National Science Foundation, Grant No. BCS90-02754. Data 

processing and analysis was supported in part by the Southern California Injury Prevention Research Center under 

Grant No. R49-CCR903622 from the Centers for Disease 

Control, the Southern California Earthquake Preparedness 

Project, and The Bay Area Regional Earthquake Preparedness Project. The authors wish to thank Gloria L. Krauss 

for editing and clerical assistance, and Kathryn Scott for 

assisting with data processing and analysis. 

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B22 PUBLIC RESPONSE 

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33-46. 
THE LOMA PRIETA, CALIFORNIA, EARTHQUAKE OF OCTOBER 17,1989: 

SOCIETAL RESPONSE 

PUBLIC RESPONSE 

CITIZEN PARTICIPATION IN EMERGENCY RESPONSE 

CONTENTS 

By Paul W. O'Brien and Dennis S. Mileti, 

Colorado State University 

Abskact .......................................... - ---------------- Introduction -----me-------------------------------- - --------------- 

Data collection ................................................... Data and findings - ............................................... Experience with the earthquake ---- - ------ - -------------- 

Public response to the emergency ....................... Accounting for differences in public response -------- Measurement------------------------------------------ 

Results .................................................. Conclusions------------------------------------------------------- 

Acknowledgments ............................................... References ........................................................ 

Page 

23 

23 

24 

24 

24 

25 

26 

27 

27 

28 

28 

29 

29 

1970). Although often stated in the published record, 

Dynes (1970, p. 84) has provided an articulate summarizing statement: 

disasters create unity rather than disorganization. The consequence of a 

disaster event on a locality is in the direction of the "creation" of community, not its disorganization, because during the emergency period a consensus of opinion on the priority of values within a community emerges; 

a set of norms which encourages and reinforces community members to 

act in an altruistic fashion develops; also, a disaster minimizes conflict 

which may have divided the community prior to the disaster event. 

Additionally, Gillespie (1988) has called for a statistical 

test of this long-standing theory. Finally, the reasons why 

disasters minimize community conflict have been cataloged 

(Dynes and Quarantelli, 1971, as summarized in Drabek, 

1986, p. 180): 

ABSTRACT 

This report describes public involvement in Santa Cruz 

and San Francisco Counties during the first several days 

after the Loma Prieta earthquake. Additionally, the public's 

experience with the earthquake and the resulting damage 

that was incurred are described. Finally, differences in public response to the disaster are explained. It is concluded 

that the level of victimization and not collective identity 

determined public involvement in response to the disaster. 

INTRODUCTION 

A recurring and common theme of sociological investigations of disasters has been that mass emergencies create 

a consensus of opinion out of which emerges an altruistic 

collective emergency response. Early empirical work (see 

Kutak, 1938; Wallace, 1956), initial attempts to theorize 

upon the empirical observations of others (see Barton, 

1970; Fritz, 1961, 1968; Demerath and Wallace, 1957), efforts to catalog research findings (Drabek, 1986; Mileti 

and others, 1975), and assessments from purely theoretical 

viewpoints (Wenger, 1985; Turner and Killian, 1986) 

agree that emergencies produce norms that foster helping 

behavior and a therapeutic community response (Barton, 

Conflict in a disaster community is minimized because: (1) the precipitating event is outside the community system, (2) a consensus on a hierarchy of values quickly emerges within the community, (3) emergency 

period problems require immediate and apparent actions, (4) disasters 

produce a "present" orientation which minimizes previous memories of 

and future opportunities for conflict, (5) disaster reduce status differences, 

(6) disaster tend to strengthen community identification. 

The theoretical basis for observed therapeutic collective 

response to disaster is linked to the concept of symbolization. Disasters create an image that is simple, compelling, 

and shared by those who experience the event (Turner and 

Killian 1986, p. 64). The shared image or symbol becomes 

a point of object (Blumer, 1951), or a generalized belief 

(Smelser, 1962), which simplifies an otherwise complex 

situation that then facilitates human action. More elaborate 

reviews of the theoretical bases for altruistic disaster response are available from Wenger (1985), Quarantelli 

(1978), and others. Nevertheless, it seems clear that symbolization of a disaster as an object is central to involvement in collective action. 

Symbolization and objectification need not only result 

from experiencing the event. They can also result from exposure to media accounts of the disaster (Barton, 1970, p. 

217), since empathy for victims and media-induced symbolization can result in nonvictim objectification and subsequent collective action. 
B24 PUBLIC RESPONSE 

Consequently, it was hypothesized that citizen involvement in response to the Loma Prieta earthquake emergency would (1) result as a consequence of victimization and 

(2) increase as a consequence of factors which could enhance symbolization such as pre-event hazard salience and 

experience. It was also suspected that involvement in response to the emergency would not be influenced by demographic characteristics such as age, ethnicity, gender, 

socio-economic status, community integration, and role 

membership since symbolization and objectification would 

not vary by such structural characteristics. 

POPULATIONS AND SAMPLES 

Two populations were selected for study. San Francisco 

County was chosen because residents had high post-mainshock media exposure; the World Series had just began in 

San Francisco, and the many reporters present readily 

switched their efforts from sports to earthquake coverage. 

Santa Cmz County was selected because it was close to 

the earthquake's epicenter, because it experienced proportionately greater damage than did the Bay Area, and because the area almost experienced a media blackout due to 

earthquake damage during the first days of the emergency. 

A comparison of findings from Santa Cruz and San Francisco Counties would enable us to determine if public involvement in emergency response varied because of 

proportionate damage and media exposure. 

A complete enumeration of residents and household addresses in San Francisco and Santa Cruz Counties was 

purchased from a private firm. These lists were relatively 

current since they are updated every 90 days. A systematic 

random sample of households was selected from each 

population list. A random number generator was used to 

determine random starts in drawing the samples from the 

population lists of 369,761 for San Francisco and 86,212 

for Santa Cruz. The sampling fraction used was 1 out of 

186 in San Francisco and 1 out of 44 in Santa Cmz. Different sampling fractions were used in order to obtain 

samples of similar size in the two study counties. These 

fractions produced sample sizes of 1,986 and 1,933 for 

San Francisco and Santa Cruz, respectively. These sample 

sizes are larger than the number needed to statistically represent the study populations. We oversampled both populations in order to achieve an acceptable number of 

completed responses after eliminating nonparticipants. 

DATA COLLECTION 

The questionnaire was constructed following the 

Dillman (1978) method to enhance response rates. It had a 

folded booklet format, a smooth flow of questions, and 

clear instructions and transitional phrases to make the instrument understandable. The first page of the questionnaire included the cover letter. The questionnaire was 

pretested on members of the general public, other colleagues, and members of a California earthquake organization who were familiar with both populations. The 

questionnaire was revised based on these pretests. 

The questionnaire, cover letter, and return envelope were 

mailed to respondents twice. The first mailing occurred on 

June 6, 1990, and the follow-up mailing occurred on July 

13, 1990. The response rate for San Francisco County was 

41 percent, and it was 50 percent for Santa Cruz County; 

these response rates resulted in sample sizes of 734 and 

918 for San Francisco and Santa Cruz, respectively (table 

1). The original sample sizes were reduced for a variety of 

reasons including undeliverable mail, moved with no forwarding address, and so on. 

The samples were assessed for representativeness by 

comparing observed sample characteristics with published 

data on the study populations (table 2). Comparisons were 

made in reference to gender, home ownership, age, ethnicity, and average household size. Income comparisons were 

not made since only out-of-date 1980 census data were 

available on this variable. An inspection of the data in table 

2 suggests that the study samples were reasonably representative of the populations in reference to some factors, but 

not for others. For example, sample and population data on 

average household size were virtually identical; sample and 

population data on gender were very close, with the samples overrepresenting females only by about 3 percent; and 

the age distribution of respondents in the samples was close 

to those in the populations, especially when one considers 

that only heads-of-households or their spouses were asked 

to complete the questionnaire. Whites were overrepresented 

in the sample for San Francisco, but not in Santa Cmz. 

Ethnic groups were underrepresented in both samples; for 

example, Hispanic-American were underrepresented by 

about 8 percent in San Francisco and 4 percent in Santa 

Cruz. Ethnic group underrepresentation is not a surprise 

since the questionnaires were only in English. Additionally, 

renters were underrepresented by about 23 percent in San 

Francisco and by about 12 percent in Santa Cruz. 

The samples contained some bias since they underrepresent ethnic groups and renters. This suggests that our descriptive study findings may be less than totally accurate 

and should be interpreted with some caution. Nevertheless, 

sufficient variation existed on all variables assessed in the 

study to insure that sample bias would not negatively affect hypotheses testing. Additionally, sample and population data were similar on other characteristics; this was 

likely the result of our inflated sample sizes. 

DATA AND FINDINGS 

The data were analyzed in order to answer three questions about public emergency response to the earthquake. 
CITIZEN PARTICIPATION IN EMERGENCY RESPONSE B25 

Table 1 .-Sample return rates 

Sample Sample Total of 

Category for for both 

an Francisco Santa Cruz samples 

Beginning total (n) 1,933 1,986 3,919 

Undeliverable 

from first 144 153 297 

mailing 

Undeliverable 

from second 6 1 7 

mailing 

Returned too late 

for inclusion in 8 8 16 

data analysis 

Total sample 

researched (g) 1,775 1,814 3,589 

Total completed 734 918 1,652 

questionnaires 

Response rate (pet.) 41 50 46 

Table 2.-Assessment of sample representativeness 

[Valuesin percent, except for "average household size"] 

Characteristics 

-- 

San Francisco Santa Cruz 

Sample Population Sample Population 

~enderl Female 

Male 

Home ownership2 own 

Do not own 

Age in years2' 25-34 

35-44 

45-54 

55-64 

65-74 

75 and above 

~thnicity~t White 73.7 58.2 90.4 90.5 Black 4.9 12.7 .4 Hispanic 1.9 

Asian 4.1 12.3 4.5 8.7 12.7 21.7 2.1 2.6 

~vera~e' household size 2.1 2.1 2.4 2.5 

What were people's experiences with the earthquake? 

What did people do in response to the earthquake? What 

factors explained differences in public earthquake emergency response? 

'California Department of Finance, 1986, Population 

projections California counties 1980-2020: Sacramento, Calif., 

California Department of Finance. 

'U.S. Bureau of the Census, 1988, City and county data book: 

Washington, D.C: U.S. Government Printing Office, p. 56, 59, 618. 

'Age percentages do not add to 100 percent because ages 0-24 

have been excluded from the comparison. 

'Sample data on ethnicity do not add to 100 percent because 

of missing data and respondent membership in other ethnic 

categories. 

EXPERIENCE WITH THE EARTHQUAKE 

Almost everyone reported that they felt the earthquake; 

99.1 percent and 96.9 percent of the respondents in Santa 

Cruz and San Francisco counties, respectively, reported 

that they felt the mainshock. Additionally, almost everyone 

had access to media coverage about the earthquake; for 

example, 91.7 and 85.7 percent of the respondents in Santa Cruz and San Francisco counties, respectively, reported 

that they had a working radio and listened to reports about 

the earthquake. Obviously, the earthquake was in some 

way experienced by almost everyone in both study counties. The few people who reported that they did not experience the earthquake were out of town when it happened; 

these respondents also reported that they immediately 

came back after hearing about it and consequently experienced the emergency. 

Most people personalized the Loma Prieta earthquake 

disaster, whether or not they themselves suffered damage. 

Reported damage in Santa Cruz was higher than in San 

Francisco (table 3). For Santa Cruz and San Francisco, 4.7 

and 46.9, respectively, percent, of respondents reported no 

damage to household items, and 13.4 and 37.7 percent, respectively, reported no damage to their residence; however, most respondents personalized the disaster by reporting 

damage to "their" neighborhood; 98.0 percent reported 

neighborhood damage in Santa Cruz and 85.3 percent reported it in San Francisco. These percentages suggest that 

even those who did not personally experience quake damage still perceived themselves to be quake victims. Almost 

a third of San Francisco respondents reported damage in 

their neighborhoods even though they experienced no personal damage; only 2.0 percent and 14.7 percent of Santa 

Cruz and San Francisco respondents reported no damage-household items, residence, or neighborhood-of 

any kind. The earthquake and disaster losses were personalized by almost everyone regardless of actual personal 

damage experienced. 

People reported greater damage and losses in Santa Cruz 

than in San Francisco (table 3). For example, almost half 

of the respondents (46.9 percent) in San Francisco reported no personal damage, but almost everyone in Santa Cruz 

reported personal damage. Additionally, more damage of 

all kinds-slight, moderate, and severe-was reported in 

Santa Cruz than in San Francisco. Damage to household 

items was reported by 95.4 percent of Santa Cruz residents, whereas only 53.1 percent of San Francisco respondents reported such damage; damage to residences was 

reported by 86.6 and 62.3 percent of Santa Cruz and San 

Francisco respondents, respectively. Additionally, more 

losses of greater magnitude-for example, fallen walls, 

broken chimneys, uninhabitable dwellings-were reported 

in Santa Cruz than in San Francisco. Only 7.1 percent of 

San Francisco respondents reported moderate and severe 

damage to their residences, whereas such damage was reported by 35.5 percent of Santa Cruz respondents. This 

gap was even higher when damage to household items 

was considered. Only 10.0 percent of respondents in San 

Francisco reported moderate and severe damage to household items, whereas 60.5 percent of the respondents in 

Santa Cruz reported such damage. Almost 10 percent of 

Santa Cmz respondents reported that they had lost almost 

all of their household possessions; this was only reported 

by 3.8 percent of the respondents in San Francisco. The 
B26 PUBLIC RESPONSE 

Table 3.-Types and distribution of damage reported by 

respondents in San Francisco and Santa Cruz Counties 

Table 4.-Public involvement in emergency response 

activities 

-- 

an Francisco Santa Cruz 

Reported damage Percent Number Percent Number 

Neighborhood damage reported 

No damage 14.7 108 2.0 18 

Slight damage (for example 

cracks in walls) 48.1 353 13.0 119 

Moderate damage (for example 

fallen walls or chimneys) 20.7 152 50.0 459 

Severe damage (for example 

uninhabitable residence) 16.5 121 35.1 322 

Total 100.0 734 100.1 918 

Residence damage reported 

No damage 37.7 

Slight damage (for example 

cracks in walls) 55.2 

Moderate damage (for example 

fallen walls or chimneys) 6.4 

Severe damage (for example 

uninhabitable residence) .7 

Total 100.0 

Household items damage reported 

No damage 46.9 

Slight damage (several 

things) 43.1 

Moderate damage (many things) 9.5 

Severe damage (almost everything) 5 

Total 100.0 

[Respondents were able to select multiple categories in reference 

to emergency response activities performed] 

San Francisco Santa Cruz 

Emergency response activity Percent Number Percent Number 

No emergency activities performed 40.1 294 30.3 278 

Search and rescue victims 2.7 20 4.8 44 

Provided food and water to others 14.3 105 34.6 318 

Provided shelter to others 11.6 85 18.2 167 

Ceaned/removed debris 10.6 78 43.7 401 

Helped evacuate victims 3.3 24 4.0 37 

Counseled victims 8.2 60 16.6 152 

Put out fires .3 2 .7 6 

Directed traffic 2.0 15 1.5 14 

Provided medical attention to 1.9 14 3.6 33 

victims 

Total 734 918 

same pattern is revealed regarding injuries; 5.9 percent of 

the respondents in Santa Cruz reported that the earthquake 

injured a member of their household, whereas 1.4 percent 

of San Francisco respondents reported household-member 

injuries. 

The earthquake caused more injuries, damage, and direct 

losses in Santa Cruz than in San Francisco, but almost everyone in both counties experienced the event, were exposed to media reports about the disaster, and personalized 

the event regardless of experienced personal losses. 

PUBLIC RESPONSE TO THE EMERGENCY 

Despite relatively large differences in the amount of 

damage experienced in Santa Cruz and San Francisco, a 

large majority of the citizens in both counties-about 70 

and 60 percent in Santa Cruz and San Francisco, respectively-participated in some sort of emergency response 

activity (table 4). On the assumption that we can generalize from our samples to the study populations, some 

450,000 and 200,000 people in San Francisco and Santa 

Cruz, respectively, engaged in emergency response activities. For example, approximately 107,000 and 83,000 people in San Francisco and Santa Cruz, respectively, 

provided food and water to victims; 61,000 and 10,000 

helped to council victims; and 20,000 and 11,500 engaged 

in search and rescue activities. 

The greater the community need, the more likely people 

were to get involved in performing emergency response 

tasks and to do them for a longer period of time. There was 

more damage in Santa Cruz than in San Francisco, and a 

larger portion of Santa Cruz respondents reported being 

involved in response activities than in San Francisco. The 

percent of respondents providing medical attention to others was 3.6 versus 1.9 percent in Santa Cruz and San Francisco, respectively, whereas it was 43.7 and 10.6 percent 

for clearing debris, 16.6 and 8.2 percent for counseling victims, 18.2 and 11.6 percent for providing victims with shelter, 34.6 and 14.3 percent for giving people food and water, 

and it was 4.8 and 2.7 percent for being involved in search 

and rescue activities. Additionally, Santa Cruz respondents 

were more likely to engage in these activities for a longer 

period of time: 54.5 percent of Santa Cruz respondents engaged in these activities for fewer than 24 hours, whereas 

11.5 percent helped for more than 24 hours; 34.5 percent of 

San Francisco respondents helped for less than 24 hours 

and 3.7 percent participated for a longer period of time. 

Members of the public in both communities were very willing to help with emergency response and provide assistance, but the proportionately greater need for help in Santa 

Cmz likely resulted in involving proportionately more people and for a longer period of time. 

People were also more likely to help others in ways that 

required one-on-one interaction with other victims than in 

indirect ways; these activities included: giving victims 

food and water, providing shelter, and giving council to 

victims. The only exception to this finding was clearing 

debris: 43.7 percent and 10.6 percent of respondents in 

Santa Cruz and San Francisco, respectively, reported debris-clearance involvement. The large portion of citizen involvement in debris clearance in Santa Cruz was likely 

demanded by the circumstances of there being so much 

debris caused by the earthquake. 

The public was also inclined to direct their emergency 

response activities toward nonskilled tasks. Response activities requiring specialized skills were the least likely to 

be performed in both counties, whereas nonskilled tasks 

were the most likely to be performed (table 4). For Santa 

Cruz and San Francisco, respectively, the percentage of re- 
CITIZEN PARTICIPATION IN EMERGENCY RESPONSE B27 

spondents engaging in tasks that could require special 

skills were low: 4.8 and 2.7 percent for search and rescue, 

4.0 and 3.3 for helping victims evacuate, 0.7 and 0.3 percent for putting out fires, 1.5 and 2.0 percent for directing 

traffic, and 3.6 and 1.9 percent for providing medical attention. However, the percentage of respondents participating in nonskilled tasks was relatively higher; respectively 

for Santa Cmz and San Francisco the number of respondents engaged in providing food and water was 34.6 and 

14.3 percent, 18.2 and 1 1.6 percent for giving others shelter, 43.7 and 10.6 percent for clearing debris, and 16.6 and 

8.2 percent counseled victims. 

About two-thirds of the public in both counties got involved in some sort of earthquake emergency response activity. Involvement was in direct proportion to the 

emergency work demands that the earthquake imposed on 

the community. Additionally, people were more likely to 

help by engaging in activities that brought them into direct 

contact with other victims, and in ways that did not require specialized skills that many of them may have 

lacked. The earthquake was not only personalized by almost everyone, it also elicited an outpouring of identification with victims as people sought to help one another, 

and they helped in ways that they could and in proportion 

to what needed to be addressed. 

ACCOUNTING FOR DIFFERENCES IN PUBLIC 

RESPONSE 

Everyone did not get involved in emergency response, 

and in this section we explain why. Multiple regression 

analysis was performed to determine the relative effects of 

different explanatory factors on pubic involvement in response. The model proposed cast public emergency response involvement as a consequence of pre-earthquake 

cognitions such as pre-event salience of the hazard and preevent earthquake experience; the amount of damage experienced in the mainshock; and standard socio-demographic 

differences between people that existed prior to the quake. 

These included level of community integration, being in 

roles of responsibility for others, age, ethnicity, gender, and 

socio-economic status. The variables used in the multiple 

regression analysis were measured and scaled as follows. 

MEASUREMENT 

The first concept in the model (X,) was pre-event earthquake salience. It was measured by asking respondents: 

"Prior to the October earthquake had you ever done anything to prepare for an earthquake?'Responses to this 

question were coded as a dummy variable. 

Pre-event earthquake experience (X2) was measured and 

responses were coded for analysis as follows. Respondents 

were asked about the severity of the largest earthquake 

they had ever experienced prior to the Loma Prieta quake. 

Responses were coded as 0="I have never experienced an 

earthquake," and (or) "I felt it but it caused no damage,'' 

versus 1="I have experienced an earthquake and it caused 

either slight damage (for example, cracks in walls), and 

(or) moderate damage (for example, fallen walls or chimneys), and (or) severe damage (for example, dwelling uninhabitable)." 

Loma Prieta earthquake damage (X3) was scaled as a 

composite index of damage to neighborhood, residence, 

and household items. Respondents were asked if the earthquake caused any damage to their household items, their 

residence, and to their neighborhood. Responses were coded dichotomously as 0=no damage and (or) slight damage 

(for example, cracks in walls or several household items 

damaged) versus l=moderate (for example, fallen walls or 

chimneys or more than several household items damaged), 

and (or) severe damage (for example, almost all household 

items damaged or uninhabitable residence). 

Community integration (XÃˆ was intervally coded as the 

number of years that respondents had lived in their current 

residence. The question asked was: "Before the earthquake, how many years had you lived at your residence?" 

The concept of roles of responsibility (Xs) was measured 

by asking people "Including yourself, how many people 

for whom you are responsible reside in your household?" 

The responses to this question were coded intervally, as 

was the age (x6) of respondents. 

Respondent ethnicity (X7) was measured by asking the 

following question. "Which best describes your raciallethnic identification?'The provided answer categories-chinese, Japanese, other Asian, African-American, Hispanic, 

White, and other-were collapsed for analysis into O=other and l=white. Gender (X8) was coded as O=female and 

l =male. 

Socio-economic status (Xa) was scaled as a composite 

index of the respondent's education, household before-tax 

income, and occupational prestige. Each of these measures 

was transformed into a dummy variable so that the three 

could be summed to form a scale for socio-economic status. Education was dichotomized at the less-than high 

school versus high school graduate division; income was 

divided at $14,999 or less a year versus $15,000 and 

above; and occupational prestige was separated into manual and skilled labor jobs versus sales, service, managerial, 

and professional occupations. 

Finally, earthquake emergency response (X,J was measured by asking respondents: "In the first 24 hours after 

the earthquake, did you in any way (officially, unofficially, or as a volunteer) do any of the following emergency 

activities?'The list of activities from which respondents 

could choose included searched for and rescued victims, 

provided food and water to others, provided shelter to 

others cleared/removed debris, helped evacuate victims, 
B28 PUBLIC RESPONSE 

counseled victims, put out fires, directed traffic, and provided medical attention/first aid to victims. Responses 

were coded as dummy variables, and then added to create 

a scale that varied between 0 and 9. 

Table 5.-Multiple regression analysis for explanations of 

public involvement in emergency response 

[N/S, not significant] 

Variables' San Francisco2 Santa Cruz3 

Dependent Independent Coefficient Significance Coefficient Significance 

RESULTS 

The results of the analysis to predict involvement in 

emergency response were almost identical in the San Francisco and Santa Cruz samples (table 5), and our findings 

follow. First, many of the standard socio-demographic differences that distinguish people from each other in nonearthquake circumstances-for example, ethnicity, gender, 

socio-economic status, level of community integration, being in roles of responsibility for others such as having 

children, and so on-made no difference in influencing 

who did and who did not help with emergency response 

after the earthquake (table 5). All of the regression coefficients for these factors were not statistically significant in 

either Santa Cruz or San Francisco. 

Second, the explanatory factor that had the strongest 

positive effect on explaining involvement in emergency response was the same in both study counties. This factor 

was the amount of damage experienced in the mainshock. 

The regression coefficient for the effect of mainshock 

damage experienced on emergency response (X3) was 0.22 

in San Francisco and 0.17 in Santa Cruz. This suggests 

that the more damage that was personally experienced, the 

more likely people were to help others. 

Third, older age was a major constraint to becoming involved in emergency response. The regression coefficient 

for the effect of age on response (X6) was -0.17 and -0.14 

in Santa Cruz and San Francisco, respectively. It appears 

that being older kept people from participating in response. This was likely due to the physical demands that 

responding to an emergency require, or perhaps older people symbolized the disaster in a unique way. 

Fourth, pre-earthquake hazard salience was measured by 

being concerned enough about the hazard to have performed actions to mitigate risk and prepare. Persons for 

whom the hazard was more salient before the earthquake 

were more likely to become involved in emergency response than persons for whom the hazard was less salient. 

The regression coefficient for this relationship (X,) was 

0.10 in Santa Cruz and 0.11 in San Francisco. 

Fifth, pre-Loma Prieta earthquake experience was measured by having experienced damage in a prior earthquake; 

it increased the likelihood of becoming involved in emergency response in San Francisco (the regression coefficient for Xy was 0.14), but not in Santa Cruz (the 

relationship was not statistically significant) (table 5). The 

effect of having experienced damage in a prior earthquake 

on enhancing the probability of engaging in emergency 

response after the Loma Prieta event likely held in San 

I Xi - pre-event earthquake salience, X, - pre-event earthquake 

experience, X3 - earthquake damage, 3(4 -community integration, 

X, - roles of responsibility, X, - age, X7 - ethnicity, X, -gender, 

& - socioeconomic status, and Xlo - emergency response. 

Total explained variance for the San Francisco sample was 13 percent. 

Total explained variance for the Santa Cruz sample was 9 percent. 

Francisco because about half of that population (46.9 percent) did not have any damage in the Loma Prieta earthquake and the impact of prior events was able to influence 

behavior. However, almost everyone in Santa Cruz-95.3 

percent of the population-had damage from the earthquake. Consequently, the possible effect of pre-Loma 

Prieta earthquake damage may have been overshadowed 

by the widespread damage brought about by that event. 

These findings suggest that being an earthquake victim-in terms of damage experienced from the Loma 

Prieta event and (or) damage experienced in prior earthquakes-was the main reason why people were motivated 

to help other victims after the Loma Prieta earthquake. 

Additionally, pre-disaster hazard salience also led people 

to help others after the earthquake; that is, having engaged in actions to address the hazard before the disaster 

fostered engaging in actions to address the impacts of the 

hazard during the disaster. These findings held regardless 

of the social and economic differences that distinguish 

people from one another in nondisaster contexts, for example, ethnicity, socio-economic status, gender and so on. 

The one exception was that being older in age constrained 

becoming involved in responding to the emergency, and 

this may have only held because of the physical demands 

of emergency response. 

CONCLUSIONS 

The Loma Prieta earthquake was personalized and symbolized by almost everyone, and this personalization occurred regardless of the amount of actual damage that 

people experienced. In essence, almost everyone identified 

with the disaster. Additionally, public involvement in responding to the emergency was in direct proportion to the 

level of disaster-induced need that existed at the community level: the greater the demand for work in a community, 

the more individuals became involved in performing response activities and the longer they worked to perform 
CITIZEN PARTICIPATION IN EMERGENCY RESPONSE B29 

them. Finally, it seems apparent that being a victim increased the odds of helping other victims. 

These conclusions are not a theoretical surprise. It has 

been long established in the field of collective behavior in 

general, and in the area of disaster research in particular, 

that community-wide disasters elicit a therapeutic community response in which disaster victims rise to the occasion and help other victims during the immediate 

emergency period. This was certainly the case in response 

to the Loma Prieta earthquake. 

Public response to the earthquake may also suggest a 

theoretical refinement. Our findings suggest that collective 

identification with the disaster-stricken community is indeed widespread and shared among all community residents-be they direct victims of the disaster or not-as is 

generally accepted in the research and theoretical literatures. However, our data also suggest that collective identification-symbolization and objectification-may not 

directly lead to collective disaster response. It appears that 

the degree of victimization experienced played a major 

role in determining the likelihood of a person becoming 

involved in and the amount of time devoted to response. 

Consequently, collective identification may be a necessary 

but not a sufficient cause for collective action in response 

to disaster. It is possible that the degree of victimization 

experienced may be the better predictor of the degree of 

collective action observed than is objectification, as is generally theorized. 

Our findings also provide some practical insights for 

earthquake disaster emergency preparedness. For example, 

victims are an obvious and readily available resource in 

responding to earthquake disasters, and it is unlikely that 

the natural tendency for victims to help victims will cease 

to operate in future earthquake disasters. As was pointed 

out by Gillespie and Perry (1976), existing preparedness 

efforts to take advantage of emergent public activities to 

help others seem well placed. 

Additionally, current efforts to motivate communities at 

risk to take pre-earthquake steps to mitigate and prepare 

for future earthquakes, if successful, may also function to 

increase the number of people who engage in emergency 

response after the occurrence of a future earthquake disaster. Also, despite the willingness of victims to offer help to 

other victims, people may generally opt for offering assistance in line with activities that they are able to perform. 

Training to provide skills to people who are likely to experience earthquake disasters in the future may well result 

in an increase in the amount of skilled emergency response services that victims provide to other victims. Our 

data suggest that training the public in specialized emergency response skills will likely be worthwhile. 

Finally, the greatest needs and problems that must be addressed by organized government response to earthquake 

disasters may indeed be those generated by victim members of the public. Nevertheless, the victims may be best 

viewed as part of the solution rather that solely as the 

source of problems. 

ACKNOWLEDGMENTS 

This research was supported by National Science Foundation Grant Number BCS-9003472 which is gratefully 

acknowledged. However, only the authors are responsible 

for the analysis, interpretations, and conclusions made in 

this paper. The authors wish to thank Joanne Darlington 

and Colleen Fitzpatrick for their data collection and management assistance. 

REFERENCES 

Barton, A.H., 1970, Communities in disaster: a sociological analysis of collective stress situations: Garden City, New York, 

Doubleday and Company, 352 p. 

Blumer, H., 1951, Collective behavior, in Lee, A.M., ed., Principles of Sociology: New York, Barnes and Noble, 356 p. 

Demerath, N.J., and Wallace, A.F.C., 1957, Human adaptation to 

disaster: Human Organization, v. 16, no. 1-2, p. 27-30. 

Dillman, D.A., 1978, Mail and telephone surveys: the total design method: New York, Wiley, 325 p. 

Drabek, T.E., 1986, Human system responses to disaster: an inventory of sociological findings: New York, Springer-Verlag, 

509 p. 

Dynes, R.R., 1970, Organized behavior in disaster: Lexington, 

Mass., D.C. Heath and Company, 239 p. 

Dynes, R.R., and Quarantelli, E.L., 1971, The absence of community conflict in the early phases of natural disasters, in 

Smith, C.G., ed., Conflict resolution: contributions of the behavioral sciences: South Bend, Ind., University of Notre 

Dame Press, p. 200-204. 

Fritz, C.E., 1961, Disaster, in Merton, R.K., and Nisbet, R.A., 

eds., Contemporary social problems: New York, Harcourt, 

Brace and World, 694 p. 

1968, Disasters, in The international encyclopedia of the 

social sciences: New York, The Macmillan Company, 

p. 202-207. 

Gillespie, D.F., 1988, Barton's theory of collective stress is a 

classic worth testing: International Journal of Mass Emergencies and Disasters, v. 6, p. 345-361. 

Gillespie, D.F., and Perry, R.W., 1976, An integrated system and 

emergent norm approach to mass emergencies: Mass Emergencies, v. 1, p. 303-312. 

Kutak, R.I., 1938, The sociology of crises: the Louisville flood 

of 1937: Social Forces, v. 17, p. 66-72. 

Mileti, D.S., Drabek, T.E., and Haas, J.E., 1975, Human systems 

in extreme environments: Boulder, Colo., Institute of Behavioral Science, University of Colorado, 165 p. 

Quarantelli, E.L. 1978. Some basic themes in sociological studies of disasters, in Quarantelli, E.L., Disasters: theory and 

research: Beverly Hills, Calf., Sage Publications, p. 2-14. 

Smelser, N.J., 1962, Theory of collective behavior: New York, 

The Free Press, 427 p. 
B30 PUBLIC RESPONSE 

Turner, R. and Killian, L., 1986, Collective behavior (3d ed.): Washington, D.C., National Academy of Sciences, p. 109- 

Englewood Cliffs, New Jersey, Prentice Hall, 414 p. 160. 

Wallace, A.F.C., 1956, Tornado in Worcester: an explanatory Wenger, D.E., 1985, Collective behavior and disaster research: 

study of individual and community behavior in an extreme Newark, Dela., Disaster Research Center, University of Delsituation: National Research Council Disaster Study, v. 3, aware, 40 p. 
THE LOMA PRIETA, CALIFORNIA, EARTHQUAKE OF OCTOBER 17,1989: 

SOCIETAL RESPONSE 

PUBLIC RESPONSE 

PUBLIC RESPONSE TO AFTERSHOCK WARNINGS 

By Dennis S. Mileti and Paul W. O'Brien, 

Colorado State University 

CONTENTS INTRODUCTION 

Page 

3 1 

3 1 

32 

33 

34 

34 

34 

34 

3 5 

35 

39 

40 

40 

ABSTRACT 

This report is on public response to aftershock warnings after the Loma Prieta earthquake. The report reviews 

the short- and long-term aftershock warnings issued to the 

public after the earthquake. The results of past research 

are then synthesized into hypotheses tested in this research. Descriptive findings about public aftershock warning response in both San Francisco and Santa Cruz 

Counties are then reported. Finally, the causal theory of 

risk communication was tested on public perception of 

risk and response to aftershock warnings during the postimpact Loma Prieta earthquake emergency. Findings from 

samples of households in Santa Cruz and San Francisco 

Counties were consistent, confirm established propositions, 

and suggest theoretical refinement. It was concluded that 

the social psychological process which explains postimpact public warning response is not identical to the one 

which explains public response to pre-impact warnings. 

The lack of mainshock damage created a "normalization 

bias" for nonvictims. This bias limited their perception of 

risk to damaging aftershocks and protective response to 

warnings. 

Lorna Prieta earthquake damage was relatively great in 

the Santa Cruz area, and difficulties were experienced there 

in receiving information and news coverage. The earthquake was felt as far south as Los Angeles, the OregonCalifornia state line to the north, and western Nevada on 

the east. It caused 62 deaths, injured 3,757 people, left 

more than 12,000 people homeless, and 18,306 homes and 

2,575 businesses damaged. Economic impacts exceeded $6 

billion dollars, owing to interruptions in transportation, 

utilities, and communications. The earthquake was the 

most costly natural disaster that the United States has experienced since the Great San Francisco Earthquake of 1906 

(U.S. Geological Survey, 1989a). 

The mainshock was 7.1 in magnitude and was followed 

with concern over damaging aftershocks. Public aftershock 

warnings were issued during the emergency and for 2 

months thereafter. The first warning was issued at 7:15 

a.m. on October 18th. It stated (U.S. Geological Survey, 

1989a) 

An analysis of historical earthquake sequences in the past 50 years in 

California suggests that there is a 1 to 2 in 10 (10 to 20 percent) probability of a M6 or larger aftershock in the first 24 hours following the mainshock and diminishing thereafter. 

A different warning appeared in the Sun Francisco Examiner for the same time period (San Francisco Examiner, 

October 18, 1989). It stated that a possibility existed for a 

7.0 magnitude aftershock in the first 24 hours following the 

mainshock. The U.S. Geological Survey did state that there 

was a possibility for a 7.0 magnitude or greater earthquake 

on an adjacent fault in the first 24 hours after the mainshock. They declared (U.S. Geological Survey, 1989a): 

Although the likelihood is remote, there is also a possibility of a M7 or 

greater earthquake in the coming days on an adjacent segment of the San 

Andreas Fault. 

Another aftershock warning was issued for the 24- to 48- 

hour period after the mainshock at 5:00 p.m. on October 

18. It stated (U.S. Geological Survey, l989b): 
B32 PUBLIC RESPONSE 

As of Wednesday at 5:00 p.m. PDT, there is only a 2 percent chance of a 

magnitude 6.0 or larger aftershock in the next 24 hours. In the same 

period, the probability of a magnitude 5.0 or larger aftershock is 13 

percent. 

A third aftershock warning was issued on October 21, 

three days after the mainshock. This warning was made 

public at 7:00 a.m.; it reduced the probability of a 5.0 

magnitude aftershock to 8 percent (U.S. ~eolo~ical Survey, 1989~): 

At this time there is only about a one percent chance of a magnitude-6 or 

larger aftershock in the 24-hour period beginning at 7:00 a.m. PDT today. The chance of a magnitude 5 or larger aftershock in the same 24- 

hour period is eight percent. 

Finally, one full week after the earthquake, the U.S. 

Geological Survey issued another warning which was in 

effect for the balance of the year (U.S. Geological Survey, 

1989d): 

Seismologists advise that additional aftershocks are expected in the next 

few weeks to months, some possibly strong enough to cause additional 

damage, especially to structures weakened in last Tuesday's quake. 

These warnings provided an opportunity to test risk 

communication theory about public response to communicated warnings issued during an ongoing disaster for the 

first time. This theory has been built upon investigations 

of public response to risk information disseminated before 

disaster strikes (see Mileti and Sorensen, 1990; Drabek, 

1986; Mileti and others, 1975). However, a case has never 

been examined when public attention is diverted by a disaster just experienced. 

THEORY AND HYPOTHESES 

Communicating information about risk to the public occurs for different reasons, for example informing people 

about the citing of hazardous waste facilities (Kasperson, 

1986) or providing warnings of impending disaster (Perry 

and others, 198 1). The latter involves the communication 

of information to the public when a risk exists in the immediate future, such as for aftershock warnings. 

People who receive warnings of risk typically go through 

stages that shape their risk perceptions and behavior. This 

process is often modelled as a sequence; for example, hearconfirm-understand-believe-personalize-respond. The sequence may not be the same for every person, and each 

stage can be affected by characteristics of the people who 

hear warnings. These characteristics include age, gender, 

level of education, and other demographics, as well as the 

characteristics of the information, such as how frequently it 

is repeated, the source, and so on. 

The process begins when someone hears the risk information that is communicated. Second, people then typically 

attempt to confirm the warning, for example by checking 

with other people or seeking information from an alternative medium. Third, an understanding of risk is formed; 

individual meanings are attached to the information heard. 

The fourth stage is belief that the risk information received 

is accurate and that it is germane to the receiver. Usually, 

an individual must believe and personalize a warning in 

order to act. Fifth, people decide what to do and then perform that behavior. A person typically goes through the 

stages of the model each time that new warning or risk 

information is received. Response to communicated risk 

information thus follows from a series of perceptions. 

Research has documented the characteristics of the people who receive warnings that impact how they process 

risk information. These characteristics are the information 

receiver's (1) environment, (2) social attributes, and (3) 

psychological attributes. Relevant attributes of the receiver's environment when the warning is received include 

physical and social cues; for example, if it is raining when 

flood warnings are received, or if neighbors are seen evacuating in concert with hearing evacuation advisements. 

Social attributes of the receiver include (see Sorensen 

and Mileti 1987) (1) network characteristics such as 

whether or not the family is united, social ties and bonds, 

and having nearby friends and relatives (Clifford, 1956; 

Quarantelli, 1980; Turner and others, 1981; Perry, 1982, 

1987; Bellamy, 1987; Cutter, 1987); (2) resource characteristics such as having access to a car in which to evacuate or economic resources to pay for a hotel (Lachman and 

others, 1961; Dynes and others, 1979; Flynn, 1979; Mileti 

and others, 1981); and (3) demographic characteristics, 

such as sex, age, ethnicity and social class (Moore and 

others, 1963; Gmntfest, 1977; Wilkinson and Ross, 1970; 

Flynn and Chalmers, 1980; Yamamoto and Quarantelli, 

1982; Perry and others, 1982). 

Significant psychological attributes of the risk information recipient are pre-warning knowledge about the risk 

and protective actions (Sorensen, 1982; Cutter, 1987); prewarning cognitions such as locus-of-control of the recipient (Sims and Bauman, 1972; Turner and others, 1981; 

Perry, 1987); and experience with the hazard agent, for example, type and recency of experience (Wilkinson and 

Ross, 1970; Perry and others, 1980; Tonn and others, 

1990). More elaborate summaries are available elsewhere 

(see Perry, 1982; Drabek 1986; Sorensen and Mileti, 

1987), and the following conclusions illustrate how aspects of the risk information received can affect public behavior. The public can better understand communicated 

emergency risk information if it has the following characteristics: if it is specific regarding the hazard, what the 

public should do and how much time is available before 

impact (Drabek and Boggs, 1968; Perry and others, 1980; 

Quarantelli, 1984); if it is communicated over mu1 tiple 

channels (Turner and others, 1981; Rogers, 1985) and is 

frequently repeated (Turner and others, 1979; Turner, 
PUBLIC RESPONSE TO AFTERSHOCK WARNINGS B33 

1983; Rogers, 1985; Mikami and Ikeda, 1985); if it is 

from official sources (Quarantelli, 1980); and if it is confirmed (Hammarstrom-Tornstam, 1977; Perry, 1982). 

Public belief in communicated emergency risk information is enhanced by similar factors. Specific information is 

more likely to be believed (Drabek, 1969; Sorensen, 1982; 

Perry and Greene, 1982; Quarantelli, 1984), as is information that is consistent (Demerath, 1957; Mileti, 1975; 

Turner and others, 1981; Keeney and von Winterfeldt, 

1986), certain (Turner and others, 1979; Perry, 1982; Mileti and others, 1981), frequently delivered (Drabek and 

Boggs, 1968; Mileti and Beck, 1975; Turner, 1983; Perry 

and Greene, 1983), from official sources (Quarantelli, 

1980; Perry and Greene, 1983; Rogers and Nehrevajsa, 

1984; O'Riordan and others, 1989), and then confirmed 

(Danzig and others, 1958; Drabek, 1969; Perry, 1982; 

Quarantelli, 1984). 

Findings regarding public risk personalization are almost 

identical to those just reviewed. In brief, personalization 

of risk is enhanced by information which is specific (Perry 

and others, 1983), consistent (Foster, 1980), personally delivered (Perry and others, 1980), frequently repeated (Mileti and Beck, 1975), from official sources (Perry, 1979), 

and confirmed (Hodler, 1982). 

Finally, what people do in response to warnings has 

been documented to be affected by the situational perceptions of risk which people form, and communicated risk 

information which is specific (Dynes and others, 1979; 

Perry and Greene, 1982; Houts and others, 1984), clear 

(Quarantelli, 1980), delivered personally (Gray, 1981), frequently repeated (Fritz and Marks, 1954, Gruntfest, 1976; 

Perry, 1982), and then confirmed (Drabek, 1969; Liek and 

others, 198 1). 

The above research conclusions can be readily synthesized into a theory of public perception and response to 

risk information, and it can be summarized as follows. 

Public response to communicated risk information is a direct consequence of perceived risk (understanding, belief, 

and personalization), the warning information received 

(specificity, consistency, certainty, accuracy, clarity, channel, frequency source, and so on), and personal characteristics of the warning recipient (demographics, knowledge, 

experience, resources, social network, cognitions, and so 

on); and perceived risk is a direct function of both the 

warning information received and the personal characteristics of the warning recipient. However, several additional 

hypotheses were added to this model before it was tested. 

It was necessary to account for the fact that we sought to 

study public response to risk information that was issued 

in the context of an ongoing emergency. 

Disasters precipitate increased public activity, altruism, 

and collective identification with victims and community 

(see Wenger, 1985; Barton, 1970; Fritz, 1961) and theorists 

have offered varied explanations for why. These explanations include a value-added approach based on a generalized belief (Smelser, 1962), emergent norms (Turner and 

Killian, 1987; Turner, l964a, b), symbolization (Drabek 

and Quarantelli, 1967), emergent social systems (Barton, 

1970; Zurcher, 1968), crisis consensus (Dynes and Quarantelli, 1971), and others. Despite alternative emphases, there 

is agreement that disasters produce community cohesiveness and that people are drawn together in ways which 

deflate individual motives for behavior in favor of serving 

collective goals. Consequently, it was hypothesized that 

experiencing damage during the mainshock would increase 

the probability of involvement in emergency response-for 

example helping to rescue people or providing food and 

water to victims; that involvement in emergency response 

would divert attention from the receipt of aftershock warnings; and that the more people were involved in responding 

to the earthquake disaster just experienced, the less likely 

that they would be to perceive risk from aftershocks and to 

respond to aftershock warnings with personally motivated 

protective actions. 

POPULATIONS, SAMPLES, AND DATA 

COLLECTION 

Two populations were selected for study. San Francisco 

County had high post-mainshock media exposure since reporters were there to cover the World Series. Santa Cruz 

County experienced proportionately greater damage and 

little media coverage. A comparison of findings between 

counties would enable us to determine if public response 

was different because of variation in damage and media 

exposure. 

An enumeration of resident's names and household addresses in both counties was obtained, and a systematic 

random sample was selected from each sampling frame. 

The sampling fractions used were 1 out of 186 in San 

Francisco and 1 out of 44 in Santa Cruz. These fractions 

yielded samples of 1,986 and 1,933 for San Francisco and 

Santa Cruz, respectively. The populations were oversampled in order to achieve an acceptable number of completed responses. 

A mailed questionnaire was constructed, pretested, revised, and then mailed to respondents twice. The final response rate for San Francisco was 41 percent, and it was 

50 percent for Santa Cruz; these rates resulted in sample 

sizes of 734 and 918 for San Francisco and Santa Cruz, 

respectively. The original sample sizes were reduced for a 

variety of reasons beyond nonresponse, and these included 

undeliverable mail, moved with no forwarding address, 

and so on. 

The samples were assessed for representativeness by 

comparing sample characteristics with population data. 

Sample and population data on average household size 

were virtually identical; data on gender were very close 

but females were overrepresented by about 3 percent; and 
B34 PUBLIC RESPONSE 

the age distribution of respondents in the samples were 

well matched to those in the populations. Whites were 

overrepresented in the sample for San Francisco, but not 

in Santa Cruz. Ethnic groups were underrepresented in 

both samples; for example, Hispanic-Americans were underrepresented by about 8 percent in San Francisco and by 

4 percent in Santa Cruz. Last, renters were underrepresented by about 23 percent in San Francisco and by about 12 

percent in Santa Cruz. 

DESCRIPTIVE FINDINGS 

PUBLIC EXPOSURE TO THE MEDIA AND 

WARNINGS 

About three-quarters of the people in both counties 

(73.6 and 76.8 percent in Santa Cruz and San Francisco, 

respectively) reported that they used the media more than 

usual because of the earthquake. An even greater number 

of people reported that they heard warnings of aftershocks 

(83.8 percent in Santa Cruz and 78.1 percent in San Francisco). The main reason that respondents gave for not 

hearing them was that their electricity was out (22.5 and 

14.4 percent in Santa Cruz and San Francisco, respectively); the next most frequent reason given was that respondents were too busy responding to the earthquake, but this 

was only mentioned by 9.5 percent of the respondents in 

Santa Cruz and 5.2 percent in San Francisco. 

It seems clear that the Loma Prieta earthquake drew 

people to the media, and it also appears that the more 

damage that a community experienced, the more likely 

people were to hear aftershock warnings. More people in 

Santa Cruz reported hearing warnings than those in San 

Francisco despite the fact that Santa Cruz was exposed to 

less media coverage and had more damage to its infrastructure. Mainshock damage likely increased the salience of aftershock warnings, and most members of the 

public had access to a working portable radio-for example, 91.7 percent in Santa Cruz-after the earthquake. 

PERCEIVED AFTERSHOCK RISK 

Most people reported hearing aftershock warnings, but 

few were able to recall what was said about the risk. For 

example, only 43.8 and 37.3 percent of the respondents 

in Santa Cruz and San Francisco, respectively, were able 

to recall the magnitude and time window of aftershocks 

in the warnings they heard. This suggests that people 

tended to dichtomize risk; for example, the specific probabilities associated with aftershocks were not as important to them as was deciding whether or not there was a 

risk to face. 

The public perceived greater risk in Santa Cruz than in 

San Francisco, even though the level of understanding aftershock warnings was the same in both counties (table 

1). For example, 54.8 percent of the respondents in Santa 

Cruz and 56.0 percent of the respondents in San Francisco reported that they understood the warnings they heard. 

However, people in Santa Cruz (74.6 percent) were more 

likely to believe that a damaging aftershock would occur 

than those in San Francisco (65.8 percent). Additionally, 

Santa Cruz respondents were much more likely (55.2 

percent) to believe that an aftershock would cause additional injury to people than those in San Francisco (39.9 

percent). 

Aftershock warnings were understood by about half the 

people who received them, and well over half of the people in both counties did expect that a damaging aftershock would occur. However, more people in Santa Cruz 

perceived greater aftershock risk-additional damage to 

structures and injuries to people-than in San Francisco. 

Residents of Santa Cruz experienced proportionately 

greater damage in the mainshock, and consequently 

warnings of aftershocks may have left them with perceptions of greater risk. 

Objective risk was actually higher in San Francisco in 

the first 24 hours following the earthquake; the U.S. Geological Survey warned of a 7.0 magnitude or greater 

earthquake on an adjacent fault-in the San Francisco 

area-during this period. 

PUBLIC RESPONSE TO SHORT-TERM 

AFTERSHOCK WARNINGS 

The public in both counties did things to mitigate losses from aftershocks by doing what could be easily accomplished; it also appears that the more mainshock 

damage experienced in their community, the more likely 

people were to prepare for aftershocks (table 2). People 

were most likely to perform easy actions like make their 

household items safer (70.3 and 45.2 percent in Santa 

Cruz and San Francisco, respectively) and develop an 

emergency plan (43.8 percent in Santa Cruz and 31.5 

percent in San Francisco) than they were to engage in 

more difficult and time-consuming activities, such as 

make their dwelling more structurally safe (17.6 percent 

in Santa Cruz and 7.4 percent in San Francisco). Additionally, a greater proportion of people in Santa Cruz performed each of the activities asked about to ready for 

aftershocks than the people in San Francisco. 

Seeking additional information about what to do to 

ready for aftershocks appears to have been a second priority for people in both Santa Cruz and San Francisco, 

perhaps because people were busy responding to the 

earthquake. For example, only 21.8 percent of the people 

in Santa Cruz and 21.2 percent of the people in San 
--- 

PUBLIC RESPONSE TO AFTERSHOCK WARNINGS 

Table 1 .-Public perception of risk from aftershocks 

in the first 72 hours after the earthquake 

San Francisco Santa Cruz 

Public perceptions pet. n pet. n 

I understood the aftershock 56.0 411 54.8 503 

warnings 

I believed that a damaging aftershock would occur 65.8 483 74.6 685 

I believed that a damaging aftershock would occur causing additional 

injury and (or) damage 39.9 293 55.2 507 

Francisco sought general information about earthquakes; 

and only 18.6 and 14.6 percent of the respondents in 

Santa Cruz and San Francisco, respectively, sought information about aftershocks (see table 2). Yet research on 

pre-impact hazard warnings has typically concluded that 

the first and most abundant public response is to seek additional information (see Sorensen and Mileti, 1987; Perry, 1982). Data in this study suggest that a mainshock 

may be a strong environmental cue to aftershocks and 

that people may not take the time to seek out additional 

information before acting to protect themselves. In fact, 

the thing people in Santa Cruz were the least likely to do 

(13.4 percent) was look in their phone books for the 

earthquake information insert provided as a public service, yet this was the only recommended public action 

contained in the warnings disseminated. 

PUBLIC RESPONSE TO THE TWO-MONTH 

AFTERSHOCK WARNING 

The probability of occurrence for a damaging aftershock in the two months after the mainshock was relatively low; nevertheless, people in both Santa Cruz and 

San Francisco took the risk seriously and performed 

many protective actions. Almost two-thirds of the people 

in Santa Cruz (63.5 percent) and over a third of the people in San Francisco (37.7 percent) did things to make 

their household items safer from the anticipated earthquake (table 3). Additionally, 42.4 and 28.9 percent of 

the people in Santa Cruz and San Francisco, respectively, 

developed an emergency plan to use in response to a 

damaging aftershock in the two months following the 

mainshock. And 27.2 percent of the people in Santa Cruz 

and 12.4 percent of those in San Francisco made their 

dwelling structurally safer in anticipation of more earthquake damage. It appears that the public took the twomonth warning seriously. As was the case with response 

to the short-term aftershock warnings, people in Santa 

Cruz did more to make ready than did those in San Francisco. Again, this was likely the case because the warnings were probably more salient in Santa Cruz due to the 

greater amount of mainshock damage experienced. 

Table 2.-Public response to aftershock warnings in 

the first 72 hours after the earthquake 

Public response in the first 72 hours after the earthquake 

Sought general earthquake inf ormat ion 

Sought information on what to do about aftershocks 

Read earthquake information in phone book 

Developed an emergency plan 

Made household items safer 

Made dwelling structurally safer 

San Francisco Santa Cruz 

Pct. n 

Table 3.-Public response to aftershock warnings 

two months after the earthquake 

San Francisco Santa Cruz 

Public response in the two months after the earthquake Pet. n Pet. n 

Sought information on 14.0 103 18.4 169 aftershocks 

Sought information on what to do about aftershocks 13.8 101 16.8 154 

Read earthquake information in phone book 17.7 130 11.3 104 

Developed an emergency plan 28.9 212 42.4 389 

Made household items safer 37.7 277 63.5 583 

Made dwelling structurally safer 12.4 091 27.2 250 

CAUSAL DATA AND FINDINGS 

The general model used to test risk communication theory is described as follows: (1) public response to aftershock warnings is a direct consequence of both 

aftershock warning information quality and quantity or 

reinforcement; the personal characteristics of those who 

received aftershock warnings (for example, age, gender, 

ethnicity, the amount of mainshock damage experienced, 

and so on); the emergency mainshock response in which 

people engaged; and perception of aftershock risk; (2) 

perception of aftershock risk is a function of aftershock 

warning information quality and reinforcement, personal 

characteristics of aftershock warning recipients, and 

emergency mainshock response; (3) finally, emergency 

mainshock response is seen as consequence of inforrnation quality and reinforcement, and the personal characteristics of warning recipients. The model proposed is 

parsimonious and well represents risk communication 

theory at the same time, and it was operationalized as 

follows. 

Warning information quality (Xi) was measured by asking respondents what they thought about all the warnings 

they heard, and then if they agreed that they were specific, 

consistent with one another, and if it seemed like people 

were certain about what they were saying. Answers were 

coded as dummy variables and then added to form a 
B36 PUBLIC RESPONSE 

quality of aftershock warning information scale; it varied 

between 0 and 3. 

Information reinforcement (X2) was scaled to represent 

the number of warnings received through divergent channels and from varied sources. Respondents were asked if 

they received aftershock warnings from government officials, scientists, friends and relatives, and other community 

residents; and if any came over television, radio, newspapers, and word-of-mouth. All responses were coded as 

dummy variables and then added as a scale of information 

reinforcement which varied between 0 and 8. 

Pre-event earthquake salience was measured by asking 

respondents: "Prior to the October earthquake had you ever 

done anything to prepare for an earthquake?" Responses to 

this question were coded as a dummy variable. Pre-event 

aftershock knowledge (X4) was measured by asking respondents: Which best described what you knew about aftershocks before the earthquake: (1) "I did not know about 

aftershocks," (2) "They happen but do not cause additional 

damage," (3) "They happen and can cause additional damage," an4 (4) "They can cause more damage than the original earthquake." Responses were collapsed for analysis and 

coded as: O=any of the first three response categories, and 

l="They can cause more damage than the original earthquake." Pre-event quake experience (X5) was measured by 

asking respondents about the severity of the largest earthquake they had ever experienced prior to the Loma Prieta 

quake. Responses were coded as 0=no damaging quake experience versus l=damaging experience. Loma Prieta 

earthquake damage (X6) was scaled as an index of damage 

to neighborhood, residence and household items. Responses were coded as 0=no damage and (or) slight damage versus l=moderate and (or) severe damage. 

Community integration (X7) was intervally coded as the 

number of years that respondents have lived in their current residence. The concept of roles of responsibility (X8) 

was measured by asking people: "Including yourself, how 

many people for whom you are responsible reside in your 

household?'The responses to this question were 3oded intervally, as was the age (Xa) of respondents. Ethnicity (Xm) 

was measured by asking "Which best describes your 

raciallethnic identification?'Answer categories were collapsed into O=other and l=white. Gender (Xi,) was coded 

as O=female and l=male. Socioeconomic status (Xn) was 

scaled as an index of education, household before-tax income, and occupational prestige. Each of these measures 

was transformed into a dummy variable and then summed 

to form a scale for socioeconomic status. 

Earthquake emergency response (Xi3) was measured by 

asking respondents: "In the first 24 hours after the earthquake, did you in any way (officially, unofficially, or as a 

volunteer) do any of the following emergency activities?" 

The list of activities from which respondents could choose 

included searched and rescued victims, provided food and 

water to others, provided shelter to others, clearedlremoved 

debris, helped evacuate victims, counseled victims, put out 

fires, directed traffic, and provided medical attentionlfirst 

aid to victims. Responses were coded as dummy variables 

and then added to create a scale that varied between 0 and 

9. Perception of aftershock risk (Xi4) was operationalized as 

an index of risk perception that was a composite of warning 

understanding, belief in the idea that an aftershock would 

occur and cause additional general damage, and belief that 

an aftershock would occur and cause the respondent, a 

member of their family, or their residence injury or damage. People were asked if they agreed with any of the following statements: (1) "I understood the aftershock 

warnings," (2) "Did you believe that a damaging aftershock 

would occur in the first 72 hours following the October 

earthquake," and (3) "Did you believe that a damaging aftershock would occur and cause you, your family, or residence injury or damage." All responses were coded as 

dummy variables and summed to create a risk perception 

index. Finally, response to aftershock warnings (Xis) was 

measured by asking people about the activities that they 

could have performed to ready for aftershocks. Each activity was coded as a dummy variable and them summed to 

create an index of protective action response. 

The operationalized theoretical model was represented as 

follows. Emergency response (XI,) was cast as a direct 

function of warning information quality (X,), warning information reinforcement (X2), pre-event earthquake salience (X,), pre-event aftershock knowledge (X4), pre-event 

earthquake experience (X,), mainshock damage (X6), community integration (X7), roles of responsibility (x8), age 

(X,), ethnicity (Xio), gender (X,,), and socioeconomic status 

(Xlz). Perception of aftershock risk (Xi4) was taken as a 

direct function of these same factors and involvement in 

emergency response (Xi3). Finally, aftershock warning response (Xis) was modelled as a direct function of the same 

factors as well as involvement in emergency response (X13) 

and aftershock risk perception (XM). 

The model was estimated on the data from both Santa 

Cruz and San Francisco Counties. The estimated model parameters included path coefficients (betas), explained variance for each equation, and other estimates; these are 

presented in tables 4 and 5, respectively, for San Francisco 

and Santa Cruz. 

The models were assessed for specification error, multicolinearity, nonlinearity, and heteroscedasticity in order to 

determine if basic regression assumptions could be reasonably made and if the estimated model parameters were 

unbiased. 

Specification error was not determined to be a problem. 

The model included all variables suggested by prior research findings and theory. An inspection of the estimated 

model parameters (tables 4 and 5) did lead to the conclusion that the model contained some irrelevant exogenous 

variables, given how these data fit the model. The inclusion 

of irrelevant variables in a model does not bias estimated 
PUBLIC RESPONSE TO AFTERSHOCK WARNINGS 

Table 4.-Estimated parameters of the model for 

San Francisco county 

[N/S, not significant] 

Table 5.-Estimated parameters of the model for 

Santa Cruz county 

[N/S, not significant] 

Variables Path Equation 

Endogenous Exogenous coefficient Estimate a a r2 

Variables Path Equation 

Endogenous Exogenous Coefficient Eatimate a a r2 

X = warning information quality, X2 = warning information reinforcement, X = pre-event earthquake salience, X4 = pre-event aftershock knowledge X = 

pre-event earthquake experience, G6 = earthquAke5dam- age, XI = community integration = roles of respon- sibility, Xg = age, X = eththcfty, Xll = gender, x = aocoecoomc staiss x = emergency response, X = perception of aftersoci^risk, and X15 = re- sponse 

betas, but can increase standard errors depending on how 

irrelevant variables are correlated with other variables. 

However, as has been pointed out by Berry and Feldman 

(1985, p. 90) "as long as the number of cases significantly 

exceeds the number of variables the increase in standard 

error will be trivial." Since the number of cases used in this 

analysis were significantly larger (n=734 and 918) than the 

number of variables in the model, it was concluded that the 

inclusion of irrelevant variables would not bias estimated 

model parameters. 

Multicolinearity can bias model estimates because it can 

increase the standard errors of estimated regression coefficients. The models for both San Francisco (table 4) and 

Santa Cruz (table 5) were assessed for multicolinearity in 

two ways. First, multicolinearity does not impose a problem unless it approaches perfect multicolinearity. The zeroorder correlation matrices for both models (tables 6 and 7, 

respectively, for San Francisco and Santa Cruz) were inspected to determine if any correlations were around 0.80 

or higher-a typical cutoff value below which multicolinearity does not seriously bias model estimates. An inspection of the zero-order correlations in tables 6 and 7 led to 

the conclusion that coefficients were not sufficiently high 

for multicolinearity to be a problem. Second, multicolinearX = warning information quality, X = warning infoatn reinforcement X - prezevent earthquake salience X = pre-event iftershock knowledge X = pre-even; eirthquake experience X = earthqu:ke5dam- age, XI = community integration: x = roles of respon- sibility, Xg = age X = ethnic?ty, Xll = gender, i12 = socioeconomi; sta% x - emergency response, Â¥ perception of aftershockrisk, and xis = re- sponse 

ity was assessed by regressing each exogenous variable in 

each equation on all other exogenous variables; and the R2s 

for each of these regressions were inspected to see if any 

approached 1.00, which would indicate a biasing level of 

multicolinearity (Berry and Feldman, 1985). This assessment also led to the conclusion that multicolinearity was 

not a source of bias in the estimated parameters of the 

model in either data set. 

The models were then assessed to determine if the assumption of linearity could be met. Exogenous variables in 

each equation were transformed to conform to alternative 

nonlinear forms, for example the natural logarithm of X, the 

square of X, the reciprocal of X, and the squareroot of X. 

These transformed exogenous variables were then correlated with each of the endogenous variables in both models. 

None of the correlations involving the transformed exogenous variables increased substantially beyond the linear 

correlations presented in tables 6 and 7. A visual inspection 

of scatterplots also confirmed the conclusion that relationships were linear. 

The assumption homoscedasticity was also assessed by 

visual inspection of regression residuals in scatterplots for 

each relationship in both models, and it was concluded that 

this assumption was met. 
PUBLIC RESPONSE 

Table 6.-Zero-order correlation matrix for the San Francisco data 

X = warning information quality X = warning information reinforcement, X = pre-event earthquake salience, X4 = pre-ev&nt2aftershock knowledge, X - pre-event earthquake experience, X6 = earthquake damage, X7 = community integration, X8 = roles of responsi- bility, X = age, Xlo = ethnicity, Xll = gender, X12 = socioeconomic status, X13 - emergency response, X14 = perception of aftershock risk, and X15 = response 

The estimated parameters of the models for San Francisco (see table 4) and Santa Cruz (see table 5) revealed that a 

very consistent set of conclusions emerged from the model 

estimates across both counties. These conclusions confirm 

parts of established risk communication theory and add 

new insights about risk communication in the context of an 

ongoing community-wide emergency. 

First, as was hypothesized, both the quality (specificity, 

consistency, and certainty) and quantity (reinforcement) 

of aftershock risk warning information had positive direct 

and indirect-through aftershock risk perception-effects 

on public warning response. The direct effect of warning 

information quality on aftershock warning response (615,1) 

was 0.11 in both San Francisco and Santa Cruz. The indirect effect of warning information reinforcement on aftershock warning response (615,2) was 0.17 in San Francisco 

and 0.10 in Santa Cruz. The indirect effect of warning 

information quality and quantity on aftershock warning 

response through risk perception was revealed by the effect of information quality on risk perception (614,1 was 

0.11 in San Francisco and 0.17 in Santa Cruz); the effect 

of warning information reinforcement on risk perception 

(614,2 was 0.25 in San Francisco and 0.24 in Santa Cruz); 

and then by the effect of risk perception on aftershock 

warning response (615,]4 was 0.14 in San Francisco and 

0.14 in Santa Cruz). These findings are exactly what 

would be predicted by existing theory: the quality (see 

Sorensen and Mileti, 1987; Perry, 1982; Perry and others, 

1980) and quantity (see Perry, 1982; Mileti and Beck, 

1975; Drabek and Boggs, 1968) of public warnings impact public response both directly and indirectly through 

the situational perceptions of risk which people form as a 

result of the warnings they hear. Our data confirm that 

this portion of risk communication theory-which up to 

now has been based on pre-impact warning studies-is 

applicable to warnings issued to a public in the context of 

an ongoing emergency. 

Second, mainshock damage had a positive indirect effect 

on aftershock warning response through the intervening 

variable of emergency response. The amount of mainshock 

damage experienced increased the likelihood that people 

would get involved in community emergency response 

(613,6 was 0.21 in San Francisco and 0.16 in Santa Cruz) 

and getting involved in community emergency response increased the probability that people would respond to aftershock warnings with protective actions (1315,13 was 0.1 1 in 

both San Francisco and Santa Cruz). This finding was the 

exact opposite of the hypothesis proposed at the outset of 

the study. It had been hypothesized that both mainshock 

damage and getting involved in community emergency response would constrain the receipt of warnings, perception 

of aftershock risk, and warning response since these factors 

could divert public attention. In fact, the opposite was the 

case. Involvement in disaster response likely increased interaction with other victims, which likely facilitated the interpersonal communication and reinforcement of warnings. 

Several other variables in the model also facilitated aftershock warning response indirectly by first getting people 

involved in community emergency response. These were 

pre-mainshock hazard salience and experience. Pre-event 

earthquake salience enhanced aftershock warning response 

indirectly by getting people involved in community disaster 

response (613,3 was 0.1 1 in San Francisco and 0.10 in Santa 

Cruz). Pre-event earthquake experience had the same effect; 

6]3,5 was 0.14 in San Francisco; this relationship was not 

statistically significant in Santa Cruz likely because mainshock damage was great there, which could have eliminated 

the effect of prior earthquake damage from the model. 

Third, selected demographic characteristics of the people 

who received warnings constrained aftershock warning response both directly and indirectly through other variables 

in the model. Age indirectly constrained aftershock warning 

response by decreasing the probability that people would 

get involved in community emergency response (613,9 was 
PUBLIC RESPONSE TO AFTERSHOCK WARNINGS 

Table 7.-Zero-order correlation matrix for the Santa Cruz data 

X = warning information quality, X2 = warning information reinforcement, X = pre-event earthquake salience, X4 = pre-event aftershock knowledge X = pre-event earthquake experience, X = earthquake damage, X7 = community integration, X8 = roles of responsi- iity X = get X = ethnicty X = gender, X12= socioeconomic status, X13 = emergency response, Xl4 = perception of aftershock risk, and Xis = response 

-0.13 and -0.15 in San Francisco and Santa Cruz, respectively). Gender also constrained warning response directly 

in San Francisco (615,11 was -0.10); males were less likely 

to engage in protective actions than were females. Ethnicity 

indirectly constrained response by negatively impacting aftershock risk perception in San Francisco (614,10 was -0.12). 

Gender and ethnicity did not function as constraints in Santa Cruz as they did in San Francisco, perhaps because 

mainshock damage was so intense in Santa Cruz that members of both genders and all ethnic groups were convinced 

of aftershock risk. The constraining effects of demographic 

characteristics on risk perception and response to warnings 

is well established in research literature and in the theory of 

risk communication (see Mileti and Fitzpatrick, 1992; Mileti and Sorensen, 1990; Turner and others, 1986; Perry, 

1982); these findings are not a theoretical surprise. 

Fourth, pre-mainshock earthquake salience played a 

strong role in both models in predicting public response to 

aftershock warnings. It had a direct and positive effect on 

warning response (B15,3 was 0.21 and 0.12 in San Francisco 

and Santa Cruz, respectively). This was a theoretical surprise; existing theory suggests that pre-event salience impacts warning response only indirectly through its effect on 

enhancing perceived risk (see Perry, 1982; Sorensen and 

Mileti, 1987). This indirect effect was observed in these 

data, but only in Santa Cruz (614,3 was 0.14); more important a direct effect of pre-mainshock salience on response 

was observed in both communities. These data suggest that 

some people took protective aftershock actions independent 

of the warnings that were issued; that is, some people 

sought to protect themselves from aftershocks based on 

something other than warnings. It is likely that both populations have general knowledge that aftershocks occur after 

earthquakes. This likely motivated people for whom the 

hazard was salient to engage in protective actions on their 

own and independent of warnings. Theoretically, these findings suggest that mainshocks function as environmental 

cues for aftershock risk. The role that environmental cues 

play in the theory of risk communication is well established 

as directly impacting warning response (see Mileti and others, 1975; Danzig and others, 1958). These data confirm 

this important theoretical relationship. 

CONCLUSIONS 

The findings which emerged from this study confirm 

many established propositions in the theory of risk communication: (1) perceived risk has a direct and positive impact 

on responding to warnings with protective actions, (2) 

warning information quality and quantity or reinforcement 

have a direct positive effect on response, as well as an 

indirect positive effect through risk perception, (3) preevent hazard salience enhances warning response both directly and indirectly, and (4) selected demographic characteristics can constrain both perception of risk and warning 

response, for example being old, being male, or being a 

member of a nonwhite ethnic group. These findings suggest 

the conclusion that many of the established principles of 

pre-disaster warning response also apply for public warnings issued in the context of an ongoing disaster. 

However, it must also be concluded that the process 

which explains post-impact public warning response is not 

identical to the one which explains public response to preimpact warnings. These data consistently revealed that 

protective warning response was more likely for residents 

of Santa Cruz County who experienced much more proportionate damage than did residents of San Francisco; that 

becoming involved in emergency response had a consistent 

direct impact on preparing for aftershocks independent of 

warnings received; and that becoming involved in emergency response was a strong direct consequence of experiencing mainshock damage. These findings suggest a 

conclusion with both theoretical and applied significance. 
B40 PUBLIC RESPONSE 

Experiencing loss in a disaster may make subsequent 

warnings more salient, thereby enhancing the likelihood of 

engaging in protective actions in response to warnings; also, experiencing loss may enhance warning response because loss elicits collective disaster response behavior 

which may facilitate informal warning notification and reinforcement. These thoughts suggest that those who experience little or no loss in the impact of a disaster may be 

prone to a "normalization bias" when interpreting post-impact warnings for subsequent risk: "The first impact did not 

affect me negatively, therefore, subsequent impacts will also avoid me." This bias may also operate in a pre-impact 

warning circumstance; for example, it may be why persons 

without any disaster experience are more reluctant to personalize risk and respond to pre-impact warnings, whereas 

those with experience are more apt to respond, holding all 

other factors constant. Normalization may operate less in 

the latter case because of recollected experience with disaster. Nevertheless, it does appear that in post-impact warning 

circumstances the effect of not experiencing damage in the 

first impact may be to create a strong normalization which 

operates to constrain perceived risk and protective response 

even in the face of warning information. 

Practically, this conclusion suggests that successful postimpact public warnings may be both easier and more difficult to achieve at the same time. The aftershock warnings 

which followed the Loma Prieta earthquake did not possess 

the characteristics of warnings known to facilitate public 

response; for example, the warnings were not specific about 

the risk faced and what people should have done to protect 

themselves. Nevertheless, they were acted upon by members of the public who experienced mainshock damage. 

This suggests that simple warnings which would convince 

few to act in a pre-impact circumstance may be enough to 

convince post-impact victims to act. It also suggests that 

post-impact victims who experienced no damage may be 

harder to convince to take protective actions than is the 

case with pre-impact warnings. 

ACKNOWLEDGMENTS 

This research was supported by National Science Foundation Grant Number BCS-9003472, which is gratefully 

acknowledged. However, only the authors are responsible 

for the analysis, interpretation and conclusions made in 

this report. The authors wish to thank Joanne Darlington 

and Colleen Fitzpatrick for their data collection and management assistance, and the anonymous reviewers of an 

earlier version of this paper for their useful comments. 

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

SOCIETAL RESPONSE 

PUBLIC RESPONSE 

EMERGENCY SHELTERING AND HOUSING OF EARTHQUAKE VICTIMS: 

THE CASE OF SANTA CRUZ COUNTY 

CONTENTS 

By Robert C. Bolin and Lois M. Stanford, 

New Mexico State University 

Page 

43 

43 

43 

44 

45 

46 

47 

48 

49 

50 

50 

ABSTRACT 

This report examines selected issues involved in the 

provision of emergency shelter, temporary shelter, and 

temporary housing for a large population of victims in 

Santa Cruz County after the Loma Prieta earthquake. The 

focus of the report is on the special shelter and housing 

problems of ethnically diverse disaster victims who are 

marginalized by demographic and socioeconomic factors. 

Of specific concern are the elderly, Hispanic and Mexican 

farm workers, and the chronically homeless. The report 

concludes with a series of recommendations on dealing 

with a diverse set of post-earthquake shelter and housing 

issues. 

INTRODUCTION 

One of the critical issues following major natural disasters is the sheltering and housing of displaced persons. 

The Loma Prieta earthquake created, in the course of less 

than a minute, a homeless population numbering more 

than 12,000 (U.S. Geological Survey, 1990) in northern 

California. Although this is only a small fraction of the 

total population of the stricken area, providing shelter for 

these newly homeless became a major organizational task 

for emergency responders in the San Francisco Bay area 

and in the less urbanized counties to the south. 

In this report we will investigate selected issues involved 

in the provision of short-term shelter and housing for a 

large population of victims. We will concentrate on the cities of Santa Cruz and Watsonville in Santa Cruz County, 

sites with the highest proportional losses of housing stocks 

in the region. Much of our discussion will draw on our 

research on the particular shelter and housing difficulties 

that confronted an ethnically and demographically diverse 

set of marginal groups. Included among these marginalized 

victims of the Loma Prieta disaster were elders, MexicanAmerican and Mexican farm workers, and the chronically 

homeless. Because of the relatively short-term nature of 

our research, we will concentrate our discussion on emergency and temporary shelter as used in the first three 

months after the disaster (Bolin and Stanford, 1990). 

BACKGROUND 

The information presented in this report was obtained 

during two separate data-gathering efforts in the impacted 

areas of northern California. The first was for a 9-day period in early November, two weeks after the mainshock had 

occurred. The second research period took place during the 

first week of January 1990. Funding for this research was 

provided by the Natural Hazards Research and Applications Information Center at the University of Colorado as 

part of their "Quick Response" research program. 

The data-gathering strategy during the first period involved interviewing regional and local Red Cross personnel 

involved in shelter operations in Hollister, Watsonville, Pajaro, Santa Cmz, and San Francisco. In addition, city and 

county officials involved in shelter and housing activities 

were interviewed in Santa Cruz, Watsonville, and Pajaro. 

During the second site visit, interviewing was broadened to 

include, in addition to Red Cross personnel, representatives 

from the Federal Emergency Management Agency (FEMA), municipal government representatives, and local 

community activists involved in temporary shelter and 
B44 PUBLIC RESPONSE 

housing issues. Because temporary housing issues were 

most pronounced in Watsonville and Santa Cruz, we restricted our second phase interviewing to those sites. In 

addition to the two phases of interviewing, published accounts of the disaster from local newspapers in Santa Cruz 

and Watsonville were reviewed to construct a general chronology of emergency and restoration activities regarding 

shelter and housing during a three-month period after the 

earthquake. All interview materials were content analyzed 

to identify key housing issues and problems as well as to 

reconstruct a broad overview of organizational activities 

related to the provision of shelter during the emergency. 

PREVIOUS RESEARCH 

We will rely on Quarantelli's (1982, 1985) typology of 

post-disaster housing as a general orienting perspective. 

Briefly, Quarantelli's perspective conceptualizes sheltering 

as a heterogeneous social process that moves through a 

series of stages or phases after disaster impact. In temporal 

sequence from disaster impact the phases are: emergency 

shelter, temporary shelter, temporary housing, and lastly, 

permanent housing. 

Emergency shelter refers to relatively unplanned and 

spontaneously sought provisional shelter. Such shelter is 

used by victims in the immediate pre- or post-impact 

phases of a disaster and is based on proximity or opportunity, rather than, in many instances, on pre-disaster planning. Often areas become de facto emergency shelters 

simply because disaster victims gather there. Quarantelli 

(1982) rightly points out that victims will tolerate relatively harsh conditions in these sheltering circumstances because of the assumed short-term nature of their 

occupation. 

Emergency shelters are frequently established by victims 

themselves on an impromptu basis. In the case of earthquakes, victims will often camp in their own yards or in 

parks near their homes. Victims will typically occupy 

these shelters only until they feel it is safe to return to 

their homes, or until they move to established temporary 

shelters (Bolin and Stanford, 1990). 

In the U.S., particularly for disasters with forewarning 

and proactive evacuations, the emergency shelter phase is 

effectively bypassed as victims go directly to temporary 

shelters (although these may, in fact, be referred to as 

emergency shelters by organizations involved). These 

emergencyJtemporary facilities are typically mass sheltering arrangements in large public buildings (schools, armories and so forth). These collective shelters are 

routinely planned for, equipped, and managed by the Red 

Cross. It is well documented in the disaster literature 

(Quarantelli, 1982; Drabek, 1986; Davis, 1977) that such 

emergency collective shelters are avoided by the public if 

they are able to make alternative sheltering arrangements. 

Thus temporary shelters are established when victims remain at a place long enough to require more elaborate facilities and services to sustain them for longer term 

occupancy (Quarantelli, 1982). Such services require planning and the involvement of emergency management organizations. The Red Cross, as noted above, is the usual 

provider of such services in temporary shelters. In situations where a portion of the community escapes damage, 

victims may be "absorbed" as evacuees into the homes of 

nonvictims, usually relatives or friends, a process obviously dependent on the existence of social support networks 

(see Bolin, 1982). Mass shelters tend to be underutilized 

by victims if they have access to these other types of shelter arrangements. 

It is difficult for emergency planners to anticipate how 

many victims will go to the homes of kin or friends for 

emergency shelter. Thus, it is virtually impossible to predict how many victims may actually show up at emergency or temporary shelter facilities following a significant 

disaster (Quarantelli, 1982). In planning for these facilities, flexibility is necessary to respond to unanticipated 

and often fluctuating demands over the course of the 

emergency period (Quarantelli, 1985; Bolin, 1989). 

Temporary housing, the next phase, identifies housing 

facilities in which victims can reestablish household routines but they have "the understanding that more permanent quarters will be obtained eventually" (Quarantelli, 

1985, p.130). FEMA is the agency typically associated 

with the provision of temporary housing assistance, although a multiplicity of organizations and agencies may 

be involved in a given disaster (see Bolin and Bolton, 

1986; Bolin and Stanford, 1991). 

Temporary housing may become permanent housing for 

low income victims, contrary to the presumed transitional 

nature of the housing. This may be a significant concern 

for planners in instances where FEMA provides mobile 

homes as a form of temporary housing (Bolin, 1982). Disputes over whether to use trailers and where to locate trailer courts can result in delays in the establishment of 

temporary housing facilities (see Bolin and Stanford, 

1990). Likewise, there is ample evidence that mobile 

homes can be a particularly problematic form of temporary housing, in some instances compounding the stresses 

that victims experience (Golec, 1983; Erikson, 1976). 

The last phase is permanent housing, an issue that generally receives little attention from disaster planners 

(Quarantelli, 1982). The reestablishment of permanent 

housing varies directly by social class background of the 

victims and their corresponding access to aid and related 

resources (Peacock and others, 1987; Bolin, 1982; Bolin 

and Bolton, 1986). The privatized approach to permanent 

housing in the U.S. generally leaves it up to the victims to 

establish new permanent housing. This is sometimes accomplished with the assistance of government programs, 

particularly Small Business Administration (SBA) disaster 
EMERGENCY SHELTERING AND HOUSING OF EARTHQUAKE VICTIMS: THE CASE OF SANTA CRUZ COUNTY B45 

loans (Bolin, 1989). Preexisting social inequalities will 

have a marked effect on which victims are able to reestablish permanent housing and how soon after the disaster 

that is accomplished (Aysan and Oliver, 1987; Bates, 

1982; Oliver-Smith, 1986; Wijkman and Timberlake, 

1988). 

Because post-disaster housing is a complex social process, all the phases may occur simultaneously in an impacted community, with different groups of victims being in 

different stages of the housing recovery process (Bolin, 

1982; Quarantelli, 1982). Thus, some victims may still be 

in temporary shelter, whereas others have reestablished 

permanent housing (Quarantelli, 1985). This variability in 

victim needs can create a wide range of demands on agencies involved in the management of housing programs. In 

general, poorer victims will take longer to reestablish permanent homes. Consequently post-disaster housing processes will tend to mirror, and sometimes reinforce, 

preexisting social class differences in the impacted community (Oliver-Smith, 1986). 

Social class, ethnicity, and demographic factors have 

been shown to influence patterns of shelter utilization and 

aid program access after disasters (Bolin and Bolton, 

1986). In general, it is those groups with marginal predisaster resources (ethnic minorities, elderly on fixed incomes, and other lower income households) who are the 

most likely to use mass care facilities and who have the 

greatest difficulties in finding suitable temporary and permanent housing. As the number of chronically homeless 

continues to increase in the U.S., this group is becoming a 

new marginalized minority group. 

Such groups' housing problems are exacerbated by the 

effects of disasters such as the Loma Prieta earthquake. 

This is, in part, a consequence of effect of earthquakes on 

poorly constructed (unreinforced masonry) residential hotels that are often used as housing for low-income persons 

who would otherwise be homeless. It also derives from the 

fact that homeless persons are systematically excluded 

from traditional temporary housing programs as offered by 

FEMA. When an earthquake destroys residential hotels, it 

is the chronically homeless who are likely to experience 

further marginalization. 

Disaster research has frequently stressed the altruism 

and social cooperation that characterizes communities after major natural disasters (Drabek, 1986). However, this 

"therapeutic community" phase (Barton, 1970; Drabek and 

Key, 1984) may be short lived, soon to be replaced by 

preexisting community conflicts that resurface, sometimes 

in an intensified fashion. Conflicts can emerge rapidly after disasters and may in fact be generated by the disaster, 

particularly over issues of temporary housing and recovery 

strategies (Bolin, 1982, 1989; Geipel, 1982). In this sense, 

disasters can be instrumental in creating structural conditions conducive to collective movements for political action and social change (Peacock and others, 1987; OliverSmith, 1986). That is, disasters may disrupt existing patterns of social arrangements, bringing victims in similar 

circumstances together in mass shelter facilities, and help 

people to see that their problems are collective rather than 

individual. As we shall argue later, this has been one of 

the short-term unanticipated consequences of the Loma 

Prieta earthquake. 

OVERVIEW OF EMERGENCY AND 

TEMPORARY SHELTERING 

The Red Cross began establishing mass shelters within 4 

hours of the 5:04 p.m. temblor in the multicounty disaster 

area. Pre-disaster planning insured that material and facilities were quickly mobilized to provide shelter for many of 

those displaced. Initial efforts at establishing shelters were 

hampered by darkness, widespread power outages, and the 

incapacitation of telephone communications and transportation links. The large number of shelters that were opened in 

the impacted areas resulted in some initial shortages of 

trained shelter managers. Training programs were instituted 

to attempt to address that shortage (Bolin and Stanford, 

1990). 

Many victims, according to our data from Santa Cruz 

County, had no systematic source of information on shelter 

locations during the first night after the earthquake due to 

the same power outages which hampered local media 

broadcasts. Police personnel patrolled damaged areas informing victims of the location of the emergency shelters 

that were opened in the immediate aftermath, although 

most victims apparently preferred staying near, but not in, 

their damaged homes. 

While no official statistics are available, anecdotal information suggests that many of those displaced created their 

own emergency shelters in parks and athletic fields in Santa 

Cruz, Watsonville, mountain communities near Santa Cruz 

(the Summit area), Pajaro (Monterey County), and Hollister 

(San Benito County). Many simply took tents and sleeping 

paraphernalia to nearby parks to sleep, whether their home 

had sustained significant damage or not. Others used automobiles as emergency shelters, parking them in open areas 

and sleeping in them for one or more nights. 

Our data suggest that fear of aftershocks was a significant 

factor in residents' decisions not to remain in their homes. 

However, damage to mountain roads leading to Santa Cruz 

and the Summit area as well as bridge collapses effectively 

isolated a number of towns for up to 4 days. These impediments to easy travel complicated victim access to mass care 

facilities. 

According to Red Cross officials in San Francisco, some 

44 shelters were operating in the multicounty impact area 

during the peak of mass care activities approximately one 

week after the temblor. For some shelters in Santa Cruz and 
B46 PUBLIC RESPONSE 

San Benito counties, shelter populations increased steadily 

during the first week of the emergency period. At a point 

three weeks after the disaster, 30 shelters were still open in 

the federally declared disaster area, although shelter populations were beginning to decline steadily. The Golden Gate 

chapter of the Red Cross anticipated closing all Bay Area 

shelters by November 30. At the height of the emergency 

period a total of approximately 2,500 victims was being 

sheltered nightly. During the first three weeks after impact a 

cumulative total of 47,300 "bed nights" was recorded at all 

shelters in the affected areas. 

Given an estimated 12,000 to 13,000 homeless as a direct result of the earthquake (U.S. Geological Survey, 

1990), it is clear that only a minority of victims actually 

evacuated to "official" emergencyltemporary shelters. 

Sheltering in the Bay Area and Santa Cruz was complicated by the presence of a significant chronically homeless 

population who also sought shelter at Red Cross facilities. 

The Red Cross attempted to cluster various "social types" 

(elderly, families with children, homeless men) together as 

shelters were consolidated, although some victims resisted 

relocation into shelters away from former residences. Military housing facilities at the Presidio (San Francisco) were 

used for some of the shelters and a Navy ship in San Francisco Bay was designated as a shelter for some chronically 

homeless victims. 

In Santa Cruz, San Benito, and Monterey Counties, the 

Red Cross opened a total of 13 shelters, all but two of those 

being in Santa Cruz County. The maximum population for 

these shelters was approximately 1,200 nightly, 7 days after 

the earthquake. An unofficial "tent city" was established by 

Hispanic victims in a park in Watsonville where an additional 150 victims found refuge. This encampment was not 

sanctioned by the Red Cross, although that organization did 

ultimately provide food and health services. 

The Red Cross provided mass care services in Santa Cruz 

County for 66 days, an exceptionally long period for temporary shelters to be open. The last shelter was closed December 21, 1989, with 21 families in that shelter as yet 

unable to find temporary housing. A total of more than 

24,000 bed nights were provided to victims in Santa Cruz 

and adjacent county Red Cross shelters. In both the Bay 

Area and in Santa Cruz County, shelters were consolidated 

as victims located temporary housing or returned to their 

damaged homes. Shelter populations grew for approximately one week after the earthquake as homes were inspected 

and some were condemned as unsafe (red tagged). There 

was also a steady turnover in shelter populations as some 

victims found housing elsewhere; others went to shelters as 

their homes were red tagged. 

The fact that the Red Cross was providing meals to more 

than five times as many people as it was sheltering suggests 

that many were sleeping in damaged homes, often lacking 

gas, water, or electricity and obtaining meals from a mass 

care facility. Difficulties in repairing infrastructural damage, especially in the remote mountainous areas of Santa 

Cruz County, meant that many otherwise undamaged 

homes could not be used, thereby increasing loads on Red 

Cross mass care services. For example, 10 days after the 

temblor, 16,200 homes, most in Santa Cruz County, did not 

have natural gas service. 

By the third week post-impact shelter populations had 

declined to 480 in 6 shelters in Santa Cruz County. The 

majority of these victims were in shelters in Watsonville, 

where a severe pre-disaster housing shortage complicated 

relocation into temporary housing. With a number of strong 

aftershocks in the County, some victims were reluctant to 

use Red Cross shelters located in built structures due to fear 

of building collapse. 

FEMA opened its first Disaster Application Center 

(DAC) in Santa Cruz and Monterey Counties on October 

22, 1989. With the opening of the DAC's, victims could 

begin apply for temporary housing assistance. The major 

form of assistance available from FEMA was cash grants to 

displaced renters and homeowners in the counties with Federal disaster declarations. Dollar amounts available in the 

housing grants were determined by "prevailing rates" for 

rental units, in this case $960 per month in Santa Cruz 

County. For renters, assistance was available for twomonths rent, whereas homeowners were eligible for three. 

Victims who could demonstrate that the money, once granted, was actually used for temporary housing, were eligible 

for further assistance if they needed additional time in temporary housing. 

After some pronounced political pressure as reported in 

the local press, FEMA agreed in mid-November to provide 

more than 140 trailers as additional temporary housing. 

Those trailers, the majority of which were targeted for Watsonville and neighboring Pajaro, were provided as a result 

of the intractable shortage of low-income housing in the 

area. FEMA's reluctance to furnish trailers is reflected in 

one FEMA spokesperson referring to the trailers as "instant 

slums." The trailers were to be available for up to 18 months 

with a renewal review every 2 months for the occupants. 

To be eligible for either FEMA's temporary housing 

grants, or the trailers, victims had to be able to demonstrate a 30-day residency at a housing unit that was rendered uninhabitable by the earthquake. Like many other 

features of Federal relief programs, this requirement was 

criticized by community activists, although in previous disasters the residency requirement was 180 days. The demand for temporary housing was such that by November 

2, 1989, FEMA had received more than 4,000 applications 

for housing assistance. 

SHELTERING AND HOUSING ISSUES 

Santa Cruz County was the center of a number of temporary shelter problems. Growing out of these problems 
EMERGENCY SHELTERING AND HOUSING OF EARTHQUAKE VICTIMS: THE CASE OF SANTA CRUZ COUNTY B47 

have been more recent related issues regarding the relocation of victims into longer term housing facilities. The issues varied in different parts of the county as well as by 

the specific victim groups involved. The issues grew out 

of difficulties associated with providing shelter and housing to a widely divergent multicultural population, many 

of whom were marginalized by age, poverty, or ethnicity 

even before the earthquake. 

WATSONVILLE 

In Watsonville and neighboring Pajaro the delivery of 

temporary shelter and housing was complicated by a complex set of class and ethnic antagonisms that variously involved the Red Cross, FEMA, and local governmental 

agencies. These conflicts emerged over preexisting social 

inequalities and a shortage of low-income housing exacerbated, in Watsonville, by the destruction of 363 housing 

units and major damage to 574 units. A number of these 

housing units were substandard and often housed more 

than one family, a fact that complicated qualifying for 

housing aid from FEMA. FEMA regulations restrict the 

provision of temporary housing aid to one family per address. 

That those most in need of housing after the earthquake 

in Watsonville were low-income Mexican-Americans employed in the agricultural sector added cultural and political dimensions to the shelter and housing process. The 

housing problem in Watsonville was evident in the incommensurability between the low wages Hispanics receive in 

the agricultural sector and the land values and rents being 

driven up by wealthy Anglo landowners and real estate 

speculators. The upshot is that the number of workers necessary to drive a multimillion dollar agricultural production system increasingly could not afford to live in the 

areas in which they were employed. The earthquake intensified these contradictory tendencies by reducing low-rent 

housing stock further and engendering what came to be 

labeled the "housing crisis" in Watsonville. 

Of the six temporary shelter facilities in Watsonville, 

five were official Red Cross operations, and one, Callaghan Park, was not. The latter was a "tent city" established by victims in a city park and occupied by 

approximately 150 Mexican-American victims. The number of Mexican-American as well as Mexican national victims meant that bilingual emergency workers and shelter 

managers were both necessary and in short supply. 

Some of our respondents indicated a reluctance to go to 

shelters or use DAC's for fear of their residency status being challenged by Immigration and Naturalization Service 

(INS) personnel. On October 24, 1989, one week after the 

mainshock, FEMA publicly announced that their records 

would not be turned over to the INS and that aid was 

available to all legitimate victims regardless of citizenship. 

Other Hispanic victims, particularly recent Central American refugees, were hesitant to use shelter facilities due to 

the presence of uniformed, armed National Guard personnel, according to officials interviewed in our study. Those 

with recent experience in the Mexico City earthquake indicated that they simply did not want to go inside buildings, fearing collapse from aftershocks. 

The earthquake and the subsequent housing crisis highlighted the preexisting deficiencies and inequities in Watsonville housing and provided the circumstance in which a 

new political agenda could be formulated, with housing as 

its focus. What began as a relatively straightforward process of providing temporary shelter evolved rapidly into a 

highly politicized process intended to redress preexisting 

class and ethnic inequalities in the availability of housing. 

One of the foci of the emergent political struggle was 

the unofficial temporary shelter facility in Callaghan Park. 

Due to health and fire hazard concerns (tent flammability) 

the Red Cross did not want to provide services to victims 

in the camp, but instead encouraged families living there 

to relocate to existing shelters elsewhere in Watsonville 

and Pajaro. Families in the tent camp insisted on remaining there, near their old homes and with their friends and 

families. Pressure was put on the Red Cross to provide 

meals and medical services for the Callaghan Park site. 

Twelve days after the main shock the Red Cross did begin 

providing meals to the Callaghan Park group, who maintained their resistance to relocation into official shelters for 

nearly 2 months. 

Other events that added to the politicized atmosphere of 

post-disaster Watsonville included: a demonstration led by 

Caesar Chavez of the United Farm Workers, in which victims were encouraged to demand low-income housing; 

charges of racism and insensitivity to cultural needs of 

Hispanic victims in some Red Cross shelters; a Justice Department investigation into charges of discrimination 

against Mexican-Americans in the city government; a 

complaint filed against FEMA by 20 Bay Area and South 

Bay county citizen groups and community organizations 

charging systematic discrimination against low-income 

and non-English speaking victims; assertions that the National Guard forcibly removed victims from one temporary 

shelter on November 25 after the Red Cross had closed 

the facility as part of the routine consolidation of temporary shelters. 

While these events were transpiring, efforts were being 

made by a number of different groups, both governmental 

and private organizations, to find solutions to the housing 

crisis in Watsonville. The local Community Action Board 

in conjunction with the county's Housing Recovery Task 

Force developed a system of motel vouchers to utilize area 

motels as a source of temporary housing for victims who 

could not find other housing. 

As noted another source of temporary housing was the 

use of FEMA trailers. Initially FEMA did not intend to 
B48 PUBLIC RESPONSE 

bring in trailers to the Watsonville or Santa Cruz areas because, according to their data, there was adequate surplus 

housing stock available. After pressure from the Congressional Representative from the area as well as the county 

Housing Recovery Task Force, FEMA did agree to provide trailers to the Watsonville area if suitable sites could 

be located and the necessary infrastructure put into place 

for the trailers. The sites in Watsonville and Pajaro were 

duly prepared and the first trailers began arriving in the 

area December 14, 1989. Even after the first one hundred 

trailers began arriving, FEMA and the county were in disagreement over how many additional trailers were needed, 

with FEMA arguing for fewer rather than more trailers. 

The "unofficial" temporary shelter camp at Callaghan 

Park was closed on December 9, and a number of its occupants were given FEMA trailers. The Red Cross closed 

its last shelter at the County Fairgrounds in Watsonville on 

December 22, placing remaining families in motels with 

short-term occupancy vouchers. The Buena Vista Migrant 

Labor Camp near Pajaro was also utilized as temporary 

housing facilities for several months after the disaster, although it was not considered wholly suitable for habitation 

during the winter months. 

FEMA as well as the local government expressed concern that the trailer camps would become permanent housing, something that is beyond the intent of the housing 

program. There was initial evidence during the 3-month 

course of this study that this was a justifiable concern on 

FEMA's part1. For some of the displaced Mexican-American victims, the trailers provided a home that was significantly higher quality than their previous housing. 

Interviews with residents and local Mexican-American 

community organizers indicated that many local families 

were living in substandard housing, including such things 

as converted garages. Others were living "doubled" up 

with another family, resulting in combined households of 

15 or more members. For some of these victims, the trailers provided the first private family setting, with electricity 

and water, that they had experienced since moving to Watsonville. Because some see the trailers as a permanent solution to the housing crisis, this will undoubtedly 

complicate FEMA's efforts to manage the trailer courts as 

temporary housing, ultimately withdrawing trailers after 

the 18-month period of availability has expired. 

'since this research was completed a number of local 

programs in Santa Cruz County have been developed to assist 

victims with the purchase of FEMA trailers to use as permanent 

housing. Limited space available to locate trailers has 

complicated their use in Santa Cruz County as replacement 

permanent housing. The problems involved in reestablishing 

permanent housing, however, is beyond the scope of this 

research. 

SANTA CRUZ 

The shelter and housing issues in Santa Cruz and the 

Summit area involved similar concerns to those in Watsonville insofar as sheltering was complicated by a lack of 

available affordable housing. The victim population in 

Santa Cruz was more diversified by social class and less 

unified by ethnicity than Watsonville. While the disaster in 

Santa Cruz created opportunities to address the specific 

housing needs of marginalized groups such as elders, poor 

Mexican-Americans, and the chronically homeless, it was 

not characterized by the rancorous conflict seen in Watsonville. 

In managing temporary shelters in Santa Cruz, as with 

Watsonville, there were shortages of trained shelter managers and nurses, particularly those with bilingual skills. 

These shortages were complicated by the 66-day period 

that the Red Cross kept mass-care operations going. This 

meant that there were several cycles of Red Cross staff 

moving through on their normal three-week assignments. 

Both staff turnover and burnout were reported as organizational problems in the delivery of shelter services that had 

to be managed during the emergency period. 

Discussions with shelter managers from several of the 

Santa Cruz shelters indicated relatively high levels of 

emotional distress among victims, particularly children. 

Part of the Red Cross response to this was to station mental health outreach workers in shelters to help victims cope 

with their stress and anxieties. The Santa Cruz shelters, six 

in all, dealt with a diverse set of clients ranging from poor 

Mexican-Americans from the Beach Flats neighborhood to 

wealthy homeowners from the mountainous Summit area. 

As in Watsonville, there were some impromptu tent encampments established early on after the earthquake, but 

they were quickly closed by police and victims relocated 

to Red Cross shelters. Sheltering in Santa Cruz was complicated by the number of chronically homeless, including 

some who were variously described by respondents as 

b'counter-culturals" or street people. While these nondisaster homeless were allowed to use Red Cross shelters, their 

lack of verifiable addresses meant they were not eligible 

for temporary housing programs offered by FEMA. 

The earthquake did provide the impetus and the opportunity to address the lack of low-income housing and the 

permanent homeless population in Santa Cruz. In interviews, Red Cross officials indicated that homeless persons 

from San Francisco were coming to Santa Cruz because 

that city was more "congenial" to the chronically homeless. At the time of this writing planning was underway to 

construct low-income housing utilizing surplus Red Cross 

earthquake relief funds to mitigate the housing squeeze. 

Due to the destruction of several residential hotels in 

downtown Santa Cmz, approximately 500 low-income elders were displaced by the earthquake and 300 were in 

need of new housing. FEMA worked with local communi- 
EMERGENCY SHELTERING AND HOUSING OF EARTHQUAKE VICTIMS: THE CASE OF SANTA CRUZ COUNTY B49 

ty agencies to place homeless elders in suitable temporary 

facilities. The University of California, Santa Cruz, offered 

part of its campus as a possible site for FEMA trailers 

specifically intended to provide temporary housing for the 

elder victims but that plan was not implemented as of February 1990. 

Other significant shelter and housing issues in Santa 

Cruz involved the mountain communities where problems 

of access, communication, and landslide hazard complicated emergency response and the use of temporary shelters. 

Some 300 victims did occupy shelters nightly during the 

first 2 weeks after the mainshock. Red Cross shelter managers reported that a strong local ethos of "self reliance" 

made many of the Summit area victims reluctant to utilize 

Red Cross shelters. 

Temporary shelter and housing in the Summit area 

posed problems because many of the damaged homes 

were located in an area of historically high landslide hazard. A building moratorium was put into effect by the 

county of Santa Cmz in the high-hazard mountainous areas until June 1991. This meant that even if victims could 

secure SBA loans or FEMA home repair grants, they 

could not proceed with rebuilding. As a result they were 

held in "limbo" according to one respondent, often living 

in a camping trailer or tent on their property. The easing 

of this building moratorium was expected to allow victims 

to proceed to with home reconstruction, if adequate funding could be secured. However some victims' house lots 

were so heavily damaged by the earthquake that it seemed 

unlikely that building permits would be issued or that 

loans will be approved. Rebuilding in the mountains will 

also be problematic for those whose homes were constructed before strict building codes were in effect, and 

who now cannot afford to rebuild to the new codes. 

While local officials sought approval from FEMA to locate trailers in the Summit area on house lots, FEMA was 

reluctant to permit trailers to be situated in hazardous areas near the epicenter. For many areas in the mountains of 

the county, the FEMA trailers were judged too large to 

move over the roadways to homesites. One FEMA trailer 

camp was under construction at the time of this study in 

the Corralitos area, a foothill agricultural community that 

had 150 homes heavily damaged and 52 destroyed (out of 

1,032) by the temblor. In general, the earthquake was particularly disruptive of water, sewer, and septic systems in 

the mountain communities, making many homes unusable 

by victims for weeks after the mainshock. 

CONCLUDING OBSERVATIONS 

Our discussion has highlighted some of the major issues 

in shelter and housing in Santa Cruz County. Although our 

research spanned only a three-month period after the 

earthquake, it has clearly shown that pre-disaster social 

conditions combined with the differential effects of the disaster created a number of significant problems in sheltering the victims and in exacerbating longer term housing 

problems. Given the problems encountered by emergency 

response organizations in sheltering only a small fraction 

of the total at-risk population of northern California, shelter and housing problems are likely to be exponentially 

larger in the case of a strong earthquake in the Bay Area. 

The increasing numbers of urban poor, the homeless, elders, and ethnic minorities (including recent immigrants) 

in urban areas of California also will complicate the provision of shelter and longer term recovery processes after a 

great earthquake in the State (see Rubin and Palm, 1987). 

By way of summarizing and generalizing from the specifics presented above, we conclude with a series of general observations and recommendations regarding postearthquake shelter and housing issues. These conclusions 

derive from our research on Loma Prieta as well as from 

previous research on other California earthquakes (Bolin 

and Stanford, 1991). 

1. To improve emergency response programs in areas 

that have an ethnically and culturally diverse victim population, organizations and agencies involved in such programs should base planning on careful demographic and 

ethnographic surveys of potential victim populations. 

Knowledge of how victims might actually utilize disaster 

shelter services in the event of a great earthquake will 

make planning for the delivery of emergency and temporary shelter more effective. 

2. The social, political, and economic disruption of disasters can create conditions conducive to social change. 

This is most pronounced in instances where victims view 

the disaster as an opportunity and a vehicle to obtain social and economic resources historically denied them. 

These efforts at social change, because they typically challenge traditional patterns of power, privilege, and property, 

may be resisted, resulting in conflict. Disaster relief organizations may become embroiled in such conflicts or even 

become the target of disputes over relief and recovery resources, complicating the delivery of services. 

3. The presence of disadvantaged persons living in marginal housing is likely to result, after a disaster, in demands on emergency services organizations that are 

frequently unanticipated within the framework of traditional shelter and housing programs. Highly bureaucratized aid programs, particularly at the Federal level may 

not have the flexibility to adequately deal with such victims. Ethnic minorities and other marginalized groups may 

experience pronounced difficulties in working with Federal 

and State disaster bureaucracies because of language or 

cultural barriers and are likely to underutilize such programs as a result. Cultural sensitivity training for disaster 

responders, utilization of local minority residents in the response effort, combined with outreach programs may improve delivery of services to these marginal groups. 
B50 PUBLIC RESPONSE 

4. Protracted emergency periods, involving extended 

stays by victims in mass shelters, appear to have an enhanced potential for social conflict to emerge over issues 

of short-term relief as well as restoration and recovery. 

These conflicts are more likely to appear in circumstances 

where the class and ethnic divisions of a community are 

relatively pronounced before the disaster. Such conflicts 

may be mitigated through liaison efforts and cooperative 

projects involving coalitions of Federal, State, and local 

officials along with existing or emergent community 

groups in the affected communities. 

5. While earthquakes provide opportunities for redressing pre-existing problems in housing and seismic safety, 

the pressure from citizens to respond quickly in the provision of temporary housing and in reconstruction may limit 

the amount of long-range planning that can be utilized in 

addressing these concerns. Similarly, without social or political pressures to do otherwise, governmental planning 

and policies for rehabilitation and reconstruction will tend 

to reinforce pre-disaster patterns of social inequality and 

class advantages. 

6. The effectiveness of short-term responses to disasters 

involving ethnically and socio-economically diverse victims will be enhanced by the involvement of citizens and 

community groups working in conjunction with Federal, 

State and local organizations. Such coalitions are often 

able to develop locality relevant policies and programs 

that address shelter and housing needs not met by more 

traditional relief programs. 

ACKNOWLEDGMENTS 

A somewhat different version of this report appeared as 

a chapter in Bolin, R. (ed)., 1990, The Loma Prieta 

Earthquake, Monograph 50, Institute of Behavioral Science, University of Colorado. This research was supported by a Quick Response Grant from the Natural Hazards 

Information Center at the University of Colorado Boulder. We would like to thank two anonymous reviewers 

for their helpful comments on a earlier draft of this paper. 

REFERENCES CITED 

Aysan, Y.F. and Oliver, Phillip, 1987, Housing and culture after 

earthquakes: Oxford, U.K., Oxford Polytechnic, 212 p. 

Barton, Allen, 1970, Communities in disaster: New York, Doubleday, 352 p. 

Bates, Fred, ed., 1982, Recovery, change and development: A 

longitudinal study of the Guatemalan earthquake: Athens, 

Ga., Department of Sociology, University of Georgia, 

730 p. 

Bolin, Robert, 1982, Long term family recovery from disaster: 

Boulder, University of Colorado, Institute of Behavioral 

Science Monograph Series, 278 p. 

1989, Temporary sheltering after the Whittier Narrows 

earthquake: Final Report to the National Science Foundation: Department of Sociology and Anthropology, New 

Mexico State University, 158 p. 

Bolin, Robert and Bolton, Patricia, 1986, Race, religion and 

ethnicity in disaster recovery: Boulder, University of Colorado, Institute of Behavioral Science, Monograph 42, 265 

P . Bolin, Robert and Stanford, Lois, 1990, Shelter and housing issues in Santa Cruz County, in Bolin, R., ed. The Loma Prieta Earthquake: Boulder, University of Colorado, Institute 

of Behavioral Science, Monograph 50, p. 99-108. 

1991, Shelter, housing and recovery: A comparison of 

U.S. disasters: Disasters, v. 15, no. 1, p. 24-35. 

Davis, Ian, 1977, Emergency shelter: Disasters, v. 1, no. 1, p. 

23-40. 

Drabek, Thomas, 1986, Human system responses to disaster: 

New York, Springer-Verlag, 509 p. 

Drabek, Thomas and Key, William., 1984, Conquering disaster: 

Family recovery and long-term consequences: New York, 

Irvington, 487 p. 

Erikson, Kai, 1976, Everything in its path: New York, Simon 

and Schuster, 284 p. 

Geipel, Roberto, 1982, Disaster and reconstruction: London, 

Allen and Unwin, 292 p. 

Golec, J. A., 1983, A contextual approach to the social psychological study of disaster recovery: Journal of Mass Emergencies and Disasters, v. 1, no. 3, p. 255-276. 

Oliver-Smith, Anthony, 1986, The martyred city: Albuquerque, 

University of New Mexico Press, 280 p. 

Peacock, William, Killian, Charles, and Bates, Fred, 1987, The 

effects of disaster damage and housing aid on household 

recovery following the 1976 Guatemalan Earthquake: Mass 

Emergencies and Disasters, v. 5, no. 1, p. 68-88. 

Quarantelli, E.L., 1982, Sheltering and housing after major 

community disasters: case studies and general conclusions: 

Columbus, Ohio, Disaster Research Center, Ohio State 

University, 214 p. 

1985, Social support systems: some behavioral patterns 

in the context of mass evacuation activities, in Sowder, B., 

ed., Disasters and mental health: selected contemporary 

perspectives: Washington, National Institute of Mental 

Health, p. 122-136. 

Rubin, Claire, and Palm, Risa, 1987, National origin and earthquake response: lessons from the Whittier Narrows earthquake of 1987: International Journal of Mass Emergencies 

and Disasters, v. 5, no. 3, p. 347-355. 

U.S. Geological Survey, 1990, The Loma Prieta California earthquake: an anticipated event: Science, no. 247, p. 286-293. 

Wijkrnan, Anders, and Timberlake, Lloyd, 1988, Natural disasters: acts of God or acts of man?: Santa Cruz, Calif., New 

Society Publishers, 143 p. 
THE LOMA PRIETA, CALIFORNIA, EARTHQUAKE OF OCTOBER 17,1989: 

SOCIETAL RESPONSE 

PUBLIC RESPONSE 

BUILDING CONTENT HAZARDS AND BEHAVIOR OF MOBILITYRESTRICTED RESIDENTS 

By Mansour Rahimi and Glenn Azevedo, 

Institute of Safety and Systems Management, University of Southern California 

CONTENTS 

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ABSTRACT 

Recent literature indicates that preparedness and behavioral response of disabled individuals are important elements in their ability to cope with earthquake hazards 

inside buildings. A survey questionnaire was conducted to 

study behavior responses of a small sample of physically 

disabled residents (with no injuries) during the Loma Prieta 

earthquake. An action-content analysis was developed and 

applied to the respondents' sequence of activities. Wheelchair users found it difficult to control their movements. 

Severe restrictions in the respondents' physical (force and 

motion) capabilities appeared to expose a few of the respondents to potential injury-producing hazards. Nevertheless, the majority of physically disabled occupants did not 

feel vulnerable to the potential hazards caused by shaking 

forces. The majority of those who felt vulnerable, however, 

took active measures to protect themselves during and immediately after the shaking. The disabled residents in this 

study had mostly adapted their living environment for their 

normal daily activities; however, lack of earthquake preparedness was evident before and after the event. 

INTRODUCTION 

The United Nations Disaster Relief Coordinator estimated that there were 500 million disabled persons worldwide 

(United Nations Disaster Relief Coordinator, 1982). A survey from the United States indicated that between 12 and 

14 percent of the working population are disabled and that 

about another 10 percent have some activity limitation 

(U.S. Bureau of Census, 1980). For persons with disabilities related to motor functioning, the estimate is around 

23.4 million (9.6 percent of U.S. population) (Elkind, 

1990). Estimates show that the percentage of people with 

disabilities has increased significantly over the past decade 

(Finch, 1979; Elkind, 1990). Based on the new census 

data, if elderly (12.5 percent of population more than 65 

years of age) and children (7.5 percent of population less 

than 5 years of age) are added to these estimates, about 

half of the U.S. population could be classified as people 

with "special needs" during disasters and emergencies. In 

relation to earthquake situations, Aroni and Durkin (1985) 

reported that 50 out of the 133 injured persons they contacted after the 1983 Coalinga (California) earthquake had 

some type of disability. At nearly 38 percent, this percentage is larger than the overall rate of disability for that community. In an earthquake in Guatemala (February 4, 1976; 

7.5 on the Richter scale and lasted 39 seconds), the rate of 

death was the highest among children and the rate of serious injuries was the highest among elderly (Glass and others, 1977). However, this study did not include a category 

for disabled people. Moreover, Parr (1987) argued that in 

disaster situations, the needs and vulnerabilities of children 

and elderly persons may resemble those of disabled persons. If this is the case, the size of the population in a high 

risk category is relatively large. 
PUBLIC RESPONSE 

BUILDING HAZARDS AND OCCUPANT 

BEHAVIOR 

The primary cause of death, injury, and destruction in 

earthquakes results from the collapse of man-made structures (Arnold, 1 990; Noji, 199 1 ). From an epidemiological 

viewpoint, frequency and severity of earthquake casualties 

should be considered as time-dependent and dynamic 

processes (Pomonis and others, 1991) that are influenced 

by a large number of factors ranging from characteristics 

of ground motions and soil formations, typology of structures, to a multitude of social and behavioral factors. For a 

summary of research needs in this area, see Murakami and 

Durkin (1988), Jones and others (1990), and Tierney 

(1 990). 

Although structural hazards are the most significant 

causes of fatalities, recent data tend to support a notion of 

differential impact of earthquake hazards for death versus 

injuries (Alexander, 1985; Aroni and Durkin, 1985; Pollander and Rund, 1989; Ohta and Okada, 1989). There is a 

growing body of evidence that nonstructural elements and 

building contents can cause deaths and injuries and that 

the human factors mitigation strategy can be effective in 

reducing earthquake injuries. For example, the percentage 

of injuries related to nonstructural and building contents 

(for example, glass, furniture, fixtures, appliances, chemical substances) appears to be higher than investigators had 

originally believed (Ohta and Ohashi, 1980; Ohashi and 

Ohta, 1984; Bourque and others, 1991). In a recent study 

from the 1987 Whittier Narrows earthquake (M=5.9), 

Bourque and others (1991) reported that injuries occurred 

"primarily because objects fell from shelves or walls, because parts of buildings fell, because of how the injured 

person behaved during or immediately after the earthquake, or because the person fell during the earthquake." 

Occupant injuries have also been attributed to the timedependent behavior responses of individuals (Ohta and 

Okada, 1989). 

BUILDING HAZARDS FACED BY PHYSICALLY 

DISABLED 

The generally accepted belief is that disabled individuals are unable to cope with building hazards during earthquakes. Preliminary observations of residential dwellings 

of disabled individuals indicated that, generally speaking, 

our disabled individuals have not been prepared for the 

devastating consequences of a major earthquake (Tierney 

and others, 1988; Rahimi, 1990; Eldar, 1991). In a study 

conducted in Los Angeles, Tierney and others (1988) 

showed that a significant portion of the disabled individuals in that city live in earthquake-prone areas with significant structural and nonstructural hazards. In cases 

where total or partial collapse does not occur, ground 

shaking may restrict disabled occupants' access to their 

perceived or recommended safety zones, required medications, special aids and equipment, and assistance from 

others. Also, the severity of a person's disability and type 

of living arrangement may affect their ability or expectation to receive assistance from others. From a behavioral 

point of view, disabled occupants may not act in time 

and in a self-protective mode when faced with life-threatening emergency situations (Levin, 1979; Clive, 1983). 

On the other hand, there is a factor of experience that 

may enhance disabled occupants' ability to cope with and 

negotiate earthquake hazards (Sorensen, 1983). 

A hypothesis under examination here is whether a relationship exists between physical disability and an increased risk of injury during and immediately after 

earthquakes. As mentioned, this relationship is influenced 

by a number of complicated variables (causal factors) 

that may be impossible to consider simultaneously in this 

study. Therefore, the following limitations have been incorporated. The event after which this study was conducted was a magnitude 7.1 earthquake affecting mostly 

an urban setting during daytime with a relatively low 

number of death and injuries. Behavioral response data 

were taken from a section of the physically disabled population with moderate to severe functional disability in 

upper and lower extremities who received no injuries, 

mostly self-reliant, and mostly living in single structures 

which did not suffer significant damage. Selecting the 

four cities where the respondents resided was a factor 

primarily of the presence of organizations which helped 

the research team locate the participants. The research 

team interviewed any participant who passed the initial 

screening test within the timeframe available (that is, the 

sampling was not statistically randomized within the four 

communities considered). Since these disabled people 

were living independently, no case-control comparisons 

were made with the behavioral response of able-bodied 

individuals living in the same structures. No control for 

age and earthquake experience of the respondents was 

considered for selection purposes. With these restrictions, 

this research was designed as an exploratory study to 

shed some light on what physically disabled people do 

during severe shaking which may place them in injuryproducing situations. In this sense, this study is designed 

to gain basic knowledge upon which futures comparative 

research can be constructed. 

RESULTS OF THE SURVEY AND 

INTERVIEWS 

An initial step was to design a questionnaire/survey 

and its associated analysis tool for studying the behavior 

of disabled persons in an earthquake. The noncontextual 
BUILDING CONTENT HAZARDS AND BEHAVIOR OF MOBILITY-RESTRICTED RESIDENTS B53 

aspects of the questionnaire (spacing, location of questions, font size, and so forth) was based on the recommendations from Berdie and Anderson (1976). Forty-four 

questions of closed and open-ended format were included 

in the survey. This survey was designed to elicit detailed 

profiles and behavioral information from a sample of 

physically disabled persons affected by the earthquake. 

Clusters of questions provided detailed information on 

the respondents' personal characteristics, judgments on 

hazardousness of the earthquake and building contents, 

and activities performed during and immediately after the 

shaking. The content of the questionnaire was based on 

the recommendations provided by Backstrom and HurshCesar (1981) and Keating and Loftus (1984). This method can be easily used to portray time chronology of occupants' behavior in relation to the potential hazards 

present in their immediate environments. The questions 

primarily relied on memory recall by "leading" the respondent through an action-sequence step for their observable behaviors (Friedman, 1987). The sequencing of 

the activities was made possible by anchoring the beginning and end of the action depiction list within the timeframe of the occupant's perceived danger. In terms of the 

administration of this questionnaire, single and short interviews were found to be effective and audio tape recording of the interviews was necessary as back-up for 

data collection and data extraction. 

To identify potential interviewees, local organizations 

offering special services and assistance to disabled persons (for example, United Cerebral Palsy, Community 

Resources for the Disabled) were contacted. The surveys 

were administered to physically disabled occupants of 

residential dwellings in separate interview sessions (about 

90 minutes each) in the third month after the event. 

Face-to-face interviews were conducted with 33 physically disabled persons living in San Francisco, Berkeley, 

Oakland, and Santa Cruz. Within the time frame available, the research team found it difficult to perform more 

interviews. This small sample size was considered sufficient for exploratory purposes. The interviewees were 

screened for their types of disabilities. About 82 percent 

of the selected sample (27 persons) had a moderate or 

severe physical disability of the upper and lower extremities (mostly related to cerebral palsy, multiple sclerosis, 

muscular dystrophy, and spinal cord injuries). This sample was selected with the expectation that moderate to severe disabilities would create difficult conditions for selfprotective actions (Tierney and others, 1988). None of 

the interviewees experienced any significant structural 

damage and most experienced nonstructural and building 

content damages. The following sections contain some 

important findings from this study. This paper presents 

information on three sets of topics: (1) interviewees' personal characteristics and living arrangement; (2) environmental feature; and (3) interviewees' activities and 

hazard exposure during and immediately after the 

earthquake. 

PERSONAL CHARACTERISTICS AND LIVING 

ARRANGEMENTS 

The mean age of the interviewees was 37.5 years, and 

the majority (about 73 percent, 22 persons) were males. 

When asked about their disability, the categories of disability most mentioned were cerebral palsy, multiple sclerosis, neuromuscular diseases (Parkinson's and muscular 

dystrophy), and spinal cord injury. The majority of the 

respondents (about 61 percent, 20 persons) had their disabling condition for over 10 years, about 24 percent (8 

persons) had their condition for 2 to 10 years, and about 

15 percent (5 persons) for less than 2 years. Table 1 indicates that the majority of the respondents were experienced with their disability at the time of the earthquake. 

In fact, given that a large number of the interviewees had 

disabilities which confined them to wheelchairs (73 percent, 24 persons), they were able to perform most routine 

daily activities in a nonemergency situation. 

Moving around is the most frequent activity in earthquakes (see Goltz and others, 1991). For comparison purposes, we need to know whether our sample of disabled 

individuals was able to move around prior to the earthquake. Table 1 summarizes a number of moving-related 

capabilities of our sample in normal daily situations. The 

majority of the respondents (88 percent, 29 persons) were 

able to move about using their walking aids without assistance from other people. Yet, if their wheelchairs (or 

walking aids) were inoperable, only 9 percent (3 persons) 

would have been able to move about their living quarters. Even with their adaptive devices operable, 70 percent of the respondents (23 persons) could not use the 

stairs for emergency exiting. In reference to their upper 

extremity abilities, the majority of the respondents were 

able to use door knobs (79 percent, 26 persons), taps and 

valves (61 percent, 20 persons), and light switches (85 

percent, 28 persons). Overall, this is an indication that although their levels of disability were severe, the respondents were adapted to their living environments for 

normal daily activities. 

In order to have a better understanding of how they 

were able to physically handle objects, they were asked 

of their ability to push, carry, or pick up different sizes 

and weights of objects (table 2). This table suggests that 

the interviewees were able to perform the task of "pushing" easier than "carrying" or "picking-up." In addition 

to physical abilities, the perception of one's disability 

level is a motivational variable for emergency response 

to disaster situations (Vash, 1981). The respondents were 

asked to indicate their level of disability. This question 

was asked on a rating scale from zero (nothing at all) to 
B54 PUBLIC RESPONSE 

Table 1. Ability of the respondents to perform some tasks in 

daily living (nonearthquake) situations 

Table 2. Percent respondents who believed they were able 

toperform the required object manipulations during an 

earthquake 

Question 

Number responding 

Yes No 

Do you require assistance of others to move from one location to another? 4 29 

Do you require the use of walking aids? 30 3 

Do you require assistance to get out of a bed or chair? 14 19 

Can you walk up or down stairs? 10 23 

Can you open and close doors by yourself? 26 7 

Can you open and close taps or valves firmly? 20 13 

Can you turn ontoff light switches? 28 5 

[Examples for different object categories: small (S), flashlight; medium (M), medicine box; 

large (L), coffee table; largeheavy (L/H), couch] 

Question Object Category 

Which items can you pickup from the floor? 62 59 48 Not included 

Which items can you carry from one place 83 79 47 Not to another? included 

Which items can you push from one place Not 85 80 46 to another? included 

ten (bed ridden). This scale was anchored at interval distances (Borg, 1982). About one-half of the respondents 

(17 persons) described their disability as less than severe. 

About 36 percent (1 2 persons) were severely disabled, 

and the remaining 12 percent (4 persons) were very severely disabled and bedridden. Their perception were later matched against their actual medical conditions. It was 

found that the respondents had a fairly accurate perception of their loss of function. 

We were also interested in knowing whether the respondents received critical assistance from others during 

the event. About 40 percent of the interviewees (13 persons) reported that they were living alone at the time of 

the earthquake. About 45 percent (1 5 persons) lived with 

one other person, and the remainder lived with two or 

more persons. Of those who lived alone, only four persons stated that they relied on neighbors or others for assistance in emergencies. Nonetheless, about one-half of 

the interviewees (17 persons) reported that they were 

alone at the onset of earthquake shaking on October 17, 

and no one else came to their assistance during the 10 to 

15 seconds of shaking. This indicates that these individuals basically acted on their own, rather than with assistance from others, during and immediately after impact. 

Similarly, the study by Tierney and others (1988) suggested that disabled individuals living in institutional environments are slower to respond on their own and 

expect to receive assistance from others. 

ENVIRONMENTAL FEATURES 

Elements of the environment play an important role in the 

cognitive and decisionmaking processes of human beings 

(Vicente, 1990). Many earthquake injuries occur when occupants attempt to handle the objects inside a room or try to 

exit the building while objects are falling. The type of 

room, interior design and layout, type and size of contents 

vary enormously from one structure to another. About 45 

percent of the respondents (15 persons) described their living units as houses and another 42 percent as apartments or 

condominiums. Therefore, the results of this research are 

mostly related to residential dwellings. Nonetheless, there 

were similarities and differences between these spaces in 

terms of contents and nonstructural elements. In general, 

houses had more floor space and appeared to have more 

elaborate interior design. The apartment designs ranged 

from a simple one bedroom (with the kitchen opening into 

the living room) to a large two bedroom (with separate 

kitchen area). It is important to mention that during the 

course of interviews, it became evident that most respondents had customized their living spaces according to their 

specific needs. Recent advances in rehabilitation engineering have made it possible to modify and adapt living and 

work environments to accommodate a wide variety of disabilities under a variety of environmental and work-space 

design considerations (Mital and Karwowski, 1988; Rahimi 

and Malzahn, 1984). 

In a study by Howell and Epp (1978), it was stressed that 

knowledge about a building's contents and the arrangement 

of items inside living spaces is necessary for the efficient 

use of living quarters by the elderly. The design of interior 

spaces and nonstructural elements was also stressed by Raschko (1982) as an important factor in the safety of disabled occupants. These design concerns may become even 

more critical for the safety of disabled occupants during 

earthquakes. As mentioned before, surrounding objects in a 

room become hazard sources during and immediately after 

a strong earthquake. The room location and the surrounding 

objects recalled by the interviewees are listed in table 3. 

The objects ranged from a small book to a large refrigerator. An evaluation of the degree of hazard caused by these 

objects during the earthquake will be presented later. In 

addition, we felt that in order for the occupants to be aware 

of the potential hazards caused by these objects, they needed to be observant and know the location of these objects 

before the shaking. The interviewees were asked about their 

degree of familiarity with their immediate surroundings. 

About 85 percent of the people (28 persons) indicated that 

they were very familiar with their surroundings and the 

arrangements within them at the time of shaking. 
BUILDING CONTENT HAZARDS AND BEHAVIOR OF MOBILITY-RESTRICTED RESIDENTS B55 

Table 3. Type of environment (respondent location) and 

contents at the onset of earthquake 

JData were not communicated or completed for respondent 81 

Respondent Environment type Items located in immediate environment 

Institute bedroom 

Institute four bed ward Living room 

Bedroom 

Living room 

Living room Living room 

Computer room Eating area Living room Living room 

Kitchen 

Office meeting room Kitchen 

Bedroom 

Bakery patio 

Parking lot 

Office 

Living room 

Bedroom 

Classroom 

Street, in front of house 

Bathroom 

Living room Office 

Computer room Bathroom 

Doctor's office Dining room 

Outside patio 

Back bedroom 

TV, closet, plants, hospital bed 

Hospital beds, night-stand, curtains 

TV, wheelchair, frames, flower pot, refrigerator, couch, 

dining table, microwave, wall clock, phone TV 

TV, VCR, cabinet, lamp, frames, shelves, books TV, table, music system, speakers, couch, drawing table 

China clock, antique dish, planter, large shelves, desk Desk, books piled high, cabinets, boxes, computer, phone 

Tables, poued plants, lights 

Books, shelves, couch, music system, speakers, TV 

Couches, music system, speakers, fish tank, table, coffee 

Refrigerator, spice rack, cabinets, food tins, fan, oven 

Table, chairs, book shelves, music system, speakers 

Dishes, table, chairs, refrigerator, cabinets, phone 

Miniatures, statues, frames, books, table clock, TV Books, tables, chairs, potted plants, coffee cup 

Power lines, newspaper stand, phone lines, bakery patio 

Computer terminals, keyboards, shelves, desk, motor Drawing tables, dinning table, chairs, computer, overhead 

Computer, book shelves, bed, table lamps, desk, phone 

Washing machine, car, shelves with tools Computer, TV, bcd, table, bookshelves mounted, table 

Desks, tables, chairs, one wall entirely glass 

Overhead power cables, trees, chimney, automobiles Wheelchair, tub, shower seat ,overhead lamp 

Table, TV, VCR, rocking chair, books, shelves, couches 

Desk, type-writer, entertainment center on wheels, potted 

Long tables, computer terminals, IBM tape drive, VAX Door, toilet, potty chair, hanging ceramic magazine rack 

Desk, table, coffee table, computer, table lamps, frames, on floor Table, chairs, phone stand, TV Table, Kayak, tools, shelves 

Music system, speakers, computer, printer, desk, couch 

ACTIVITIES AND HAZARD EXPOSURE 

ACTIONS TAKEN DURING EARTHQUAKE 

It has been clearly documented that because building occupants do not remain stationary, they become sources of 

hazards during earthquakes (for example, Ohta and Ohashi, 

1980; Archea, 1990). Also, the safety of occupants, including persons with disabilities, is likely to depend on how 

they react during and immediately after impact and on what 

self-protection measures they are able to carry out. In order 

to obtain a better understanding of how interviewees behaved and how safe they were during the earthquake, they 

were asked to report their actions sequentially. This section 

of the questionnaire began with questions related to the 

disabled persons' body positions and their first reactions 

and continued with detailed descriptions of their activities 

until the moment that they finally felt they were out of 

danger from the initial shock. The remainder of this paper 

attempts to relate the disabled persons' physical activities 

to the corresponding degree of hazard exposure during the 

earthquake. (A set of single-paragraph summaries of the 

activity sequences for each respondent during the earthquake is available upon request.) 

The location and body position of a disabled person at 

impact may be the most important factor in terms of ability 

to react to potentially hazardous situations. For example, it 

is known that in a residential fire situation, a person was not 

able to escape the danger because he was in his bathroom 

taking a bath (Levin, 1987). In our sample, a majority of 

the respondents (94 percent, 31 persons) were in either 

standing (and walking) or sitting positions as opposed to 

kneeling, reclining, or lying. Twenty-four respondents were 

regular wheelchair users at the time of the event. The respondents* readiness to take necessary action became more 

important considering the fact that about 52 percent of the 

respondents (16 persons) were alone at the onset of shaking. Help from others was not available for these people 

during the shaking. It must be noted that behavior of disabled occupants during an earthquake may have differed if 

other people were present in the room. Single-person versus multiple-person behavior was not addressed in this research. However, there is a need to study the behavior of 

disabled persons in a group-interactive environment. 

The initial reactions of the respondents were organized 

and are listed in table 4. These actions were taken by the 

occupants at the onset of shaking. Analysis of the respondents' initial reaction is an important part of this study 

since these actions constitute the bases from which the subsequent behavior patterns can be evaluated. Based on the 

frequencies shown in table 4, 10 respondents (out of 33) 

initiated "active" mode of behavior (classification provided 

by Tierney and others, 1988). Labeled as "initial movement," these actions included moving under a door frame 

or overhead beam, standing up, sitting on the edge of a 

couch, and others. Initiation of such actions are considered 

to be an important part of a strategy for self-protection and 

safe behavior during earthquakes. "Holding on" to something was the second highest category. About one-third of 

the respondents (9 out of 33) held onto an object to counteract the forces of shaking. Most of the respondents in this 

category held onto an object to prevent from falling (one 

respondent held onto a spice rack to prevent it from falling 

on him). Approximately 33 percent of the respondents in 

this category held onto their wheelchair without initiating 

any active behavior at the onset of the earthquake. The third 

highest category of initial reactions was classed as "stayed 

put." In this category, eight respondents did not move 

much, even though they had the opportunity to do so. Some 

of the respondents did not realize the severity of the earthquake and thus did not react to the initial shaking, whereas 

others chose to stay in the same location. Nine percent (3 

respondents) reported an unconscious automatic nonresponse to the onset of the shaking (classed as "instinctive 

behavior"). These are the most extreme cases of passive 

behavior which was detrimental to the self-protective needs 

of the building occupants. Finally, only three respondents 

were engaged in only "observing" the events within their 

surroundings at the onset of shaking. 

MODE OF BEHAVIOR VERSUS FEELING OF VULNERABILITY 

OR SAFETY 

As mentioned before, an active mode of behavior involves an individual's attempt to actively enhance personal 

safety, given the nature of the individual's disability and the 
B56 PUBLIC RESPONSE 

Table 4. Respondents'first reactions and their reasons 

First reaction Frequency Reasons for actions 

Initial movement: - under door frame 

- under overhead beam - under desk 

- toward exit door - into hallway - by turning wheelchair - stood up - sat on edge of couch Held onto: - couch/wheelchair 

- table 

- spice rack - bathroom handrails 

wheelchair wheels Stayed put: - did not move much 

- in car - on phone 

- yelled for help, 

Instinctive behavior: - started spasm 

- froze 

Observation: 

- to avoid falling debris and glass - prior education - to be safe, prior knowledge - was told to do so - wanted to get out (did not succeed) - to be safe, prior knowledge - to face away from glass windows - did not know what else to do - to get away from glass windows 

- shaking was intense - to stop from falling over, due to low balance control -did not know what to do - looking at plaster falling from 

ceiline - was bouncing out of control - afraid of falling - was falling on respondent - to stop from falling over - to stay in chair 

- did not realize how bad the earthquake was 

- quake was mild - was not initially worried, had a pre-notion that morning - location was safe - to get a hug from doctor - did not know how to react - to comfort friend on the line, and 

pass on last message - unable to get out of bed on his own 

- automatic nervous reaction to stress 

- seeingand hearing others panic caused this reaction 

- turned wheelchair out of curiosity to see what was happening to the space around - to get an estimate of earthquake 

intensity - looking for phone to call daughter 

surrounding hazards encountered. For example, a number 

of respondents initiated physical actions that placed them in 

a location of perceived safety. Also, some respondents 

made every attempt to hold onto an object to prevent their 

falling. In contrast, in the passive mode, some respondents 

took no self-protective action in response to the earthquake. 

To allow for this dichotomy, the survey questionnaire contained an action sequence format based on a scenario analysis developed by Keating and Loftus (1984). This format 

led each of the respondents through a series of time-phased 

steps from the onset of shaking until the time when the 

respondents felt out of danger. Based on the activelpassive 

analysis, the sample was split almost equally between persons who reported responding in an active manner and 

those who remained passive during the shaking. It is interesting to note that Arnold and others (1982) found that only 

37 percent of the building occupants (disabled and ablebodied) stayed put during an earthquake in the Imperial 

County, California. Also, Archea and Kobayashi (1984) 

found that during the period of strong motion of an earthquake in Urakawa, Japan, respondents even increased their 

risk of injury by attempting to move about and to protect 

their personal belongings. No mention of respondents' disability was made in the Japanese sample. 

A thorough investigation of occupant behavior must also 

include some aspects of the respondents' cognitive and 

emotional states. For example, one wheelchair-confined 

person indicated that he remained in his wheelchair during 

the entire period of shaking and did not attempt to move at 

all. When asked about his feeling of vulnerability, he responded that he felt "safe." His apparent lack of active 

behavior appeared to be mediated by a perception of safety 

based on variables related to his surroundings and personal 

traits. On the other hand, another respondent who held tight 

to her wheelchair during the shaking reported feeling very 

vulnerable. Her explanation was that even if she wanted to 

move to a safer location, she decided not to do so fearing 

she might fall out of her chair. To reflect this categorization 

on the entire sample of the disabled respondents, their active or passive behavior was cross-tabulated with their feeling of vulnerability. A nonparametric correlational analysis 

was conducted to explore this relationship. A resultant phi 

coefficient of -0.34 in table 5 indicates that interviewees 

who reported feeling safe during the shaking were likely to 

also report remaining in a passive state during the shaking 

(12 out of 33 persons). On the other hand, those who reported feeling vulnerable were more likely to have taken 

some action (10 out of 33 persons). 

An important result emerges from table 5: passive behavior among the disabled respondents does not necessarily 

reflect a psychological feeling of vulnerability or fear. It is 

more probable that this passive behavior stemmed from inability to perform activities which required physical 

strength than from psychological motivations required for 

such physical exertions. It is interesting to note that this 

result is consistent with the notion of "body-mind" system 

presented by Vash (1981). She explained that there seems 

to exist a distinction between physical performance limitations (disability) and psychological underpinnings of human behavior. Contrary to our findings, McDaniel (1976) 

believed that the principle of somatopsychology produces a 

degree of "devaluation" and "spread" for disabled persons. 

Devaluation refers to the attitude of reduced self-esteem 

and self-confidence which culminates in a feeling of helplessness and dependency. Eventually, this feeling may not 

remain confined to the actual limits of the impairment; instead, disabled individuals may come to view themselves as 

being excessively incapacitated, even in situations where 

they are clearly able to function independently. 

This perceived lack of ability to actively respond may 

also be related to the individual's degree of control over the 

outcome of the natural hazard. DeMan and Simpson-Housley (1987) and Lehman and Taylor (1987) suggested that 

human psychological response to a perceived or on-going 

natural hazard is mediated by the degree of physical and 

psychological uncontrollability for the event occurrence. 

Occupants are motivated to avoid uncertainty in hazardous 

circumstances. Human beings tend to deal with such uncertainty by denying that potentially hazardous situations exist 

(Hale and Glendon, 1987). Psychological tests were not 

performed to assess the motivational variables for respon- 
BUILDING CONTENT HAZARDS AND BEHAVIOR OF MOBILITY-RESTRICTED RESIDENTS B57 

Table 5. Relationship between respondents' perceived vulnerability and type of behavior during the earthquake 

[Table shows total number of respondents with percentage of total respondents inside 

parentheses. The phi correlation coefficient for cell frequencies is -0.34, significance level is 0.051 

Activity Vulnerability 

Vulnerable Safe Total 

Passive 4(12.1) 12(36.4) 16(48.5) 

Active lO(30.3) 7(21.2) 17(51.5) 

Total 14(42.4) 19(57.6) 33(100) 

dents' reactions. However, research in fire hazard mitigation has indicated that through education and training, 

disabled people can be successfully trained to overcome 

such obstacles (Levin and Nelson, 1981; Jones and others, 

1984; MacEachron and Krauss, 1985; Pauls and Juillet, 

1989). 

HAZARDS CAUSED BY BUILDING CONTENTS 

None of the respondents were injured during the earthquake. During the shaking, a number of items fell and 

broke close to the respondents (for example, dishes, picture frames, books, light fixture, table lamps, computer 

terminal). Table 6 contains a list of fallen and broken 

items. About 67 percent (22 persons) reported items fallen 

or broken near them. They were also asked if these items 

affected their decision to take (or not to take) any safety 

action. Of those who experienced fallen and broken items, 

about 68 percent (15 persons) responded that the broken 

items did not affect their decisions to take (or not to take) 

any action. Therefore, it is quite possible that for these 15 

respondents, there was no feeling of being exposed to imminent danger and thus there was no need for immediate 

reaction or response. One person, however, was caught between a spice rack and a refrigerator while attempting to 

take an item from the refrigerator. For those whose actions 

were affected by these fallen and broken items, there was 

a definite problem of increased blocking and difficulty of 

maneuvering (with or without wheelchair). It was difficult 

to further evaluate the nature of these barriers without reenactment (simulation) of the individual cases. In this 

study, the items in table 6 were found to be potentially 

barrier producing. It is conceivable that in an earthquake 

of higher magnitude, these items could act as projectiles 

and barriers, adding to the degree of danger. 

A BEHAVIOR RISK ANALYSIS 

In order to gain a comprehensive picture of how exposed the disabled persons were to hazards caused by the 

earthquake, a quantitative analysis of disabled responTable 6. Objects fallenhroken and their effects on respondents ' decisions 

[Data were not communicated or completed for respondent 81 

Respondent Fallenbroken items Effects of items on actions 

None 

None 

Figurine from television, potted plant 

None 

Wine glasses, pottery items, potted 

plants 

None 

None 

~&p shade, records, tapes 

China clock, lamps, antique dish, 

vase, everything on book shelf Window panes, dry wall 

None 

Copper enamel plate 

Small picture frames 

Tin food, dishes None 

Dishes, glassware, lamps, books, 

figurines 

Frames, book shelves, figurines 

None 

None 

None 

Two frames None 

One dish Books, figurines, table lamp 

None 

Concrete pedestal, water cooler, 

books, paintings, sculptures, glassware, closet, sliding doors knocked open to a 30 degree angle 

Heat lamp dislodged and was hanging 

by cord, most items from shelves and closet, table lamp, 

books, figurines, glass items Books, video tapes, records 

Wall plaque 

Large computer terminal 

Water dispenser, potted plant, tin food Lamp, books None 

Chimney 

Paintings, magazine rack, pencil holder 

None 

None 

None 

Conceived serious and made respondent move 

to hallway and outside; perceived duration of shaking as long None 

None 

Front door was jammed, required a hammer to open it, broken glass may have flattened the wheelchair tires Books blocked the main door, could not go anywhere 

None 

None 

Moved backwards to avoid falling book 

Front door was blocked by plants and water cooler, debris on floor prevented easy 

maneuvering 

Did not venture into kitchen due to broken glass and having air-filled tires on wheelchair 

None (went under doorway immediately, 

things could have been worse if he had 

waited a bit longer) None 

Crashing sound led to feeling of panic and closing of eyes None 

None 

None 

None 

dents' activities was performed. This approach is a modification of a methodology developed by Yin (1989). For this 

analysis, a list of independent action categories (with a generic format) during and immediately after an earthquake 

was generated (table 7). The explanation for each action 

category shows the activity type, content, and potential 

hazards to the respondents. For example, if the initial reaction to an earthquake was to enter into an involuntary passive mode (for example, unable to comprehend the 

situation), the person was exposed to a higher risk. An 

"importance multiplier" was assigned to each item of this 

list. This importance multiplier is an independent rating 

(from 1 to 5) for the degree of correlation (dependency) 

between the action item and hazard exposure. In table 7, 

the highest correlation exists for "decision for next action," with a rating of five. In other words, in terms of 

overall exposure to hazards during an earthquake, it is extremely important to make a correct decision for action 

after observing one's location in a structure and the surrounding hazards. 

The next step was to evaluate the actions performed by 

each respondent across all the categories listed in table 7. 

In order to perform this evaluation objectively, a "hazard 

weighting factor" was constructed for these actions (table 

8). As described in table 8, the hazard weighting factor is 
B58 PUBLIC RESPONSE 

Table 7. Generic activities (physical and mental) and their 

explanations for occupant risk analysis 

Actions list 

(importance Explanation 

multiplier *) 

Initial reaction 

(4) 

Observing the 

surroundings 

(3) 

Decision for next action 

(5) 

Protective actions 

(4) 

Interaction with obstacles 

(4) 

Reaching desired goal 

(4) 

Protective actions after shaking 

!:Lraction with objects 

(2) 

Reaching desired goal 

(2) 

Examines occupant's immediate reaction to earthquake. This could be physical, conscious, or involuntary action. It indicates whether the occupant is in a position to take any action to avoid a hazardous situation. Regardless of the occupant's location, if the initial reaction is involuntary the individual is in a high-risk exposure situation. 

Respondent's degree of hazard awareness and observation of surrounding items, which could range from thorough (that is, 

complete and objective) to none at all. This activity is not as closely linked to hazard exposure as the initial reaction, or the next activity of decisionmaking. 

Decision processes are examined as a planning tool for a series of actions. A typical decision is to move or stay put after the initial observation. This is normally a conscious decision with a defined objective in mind. It is critical that an occupant does not make a risky decision that might place himher in an injury-producing situation. Occupants take a series of protective actions regardless of decisions made previously. These actions could range from being safe to risky with respect to potential hazards faced at that moment. Actions taken during the shaking period are 

responsible for occupant injury. Encounter and interaction with obstacles during the shaking 

period in an attempt to perform a task. Occupants may be involved in situations ranging from no obstacles/no difficulty to major obstacles with difficulty. Whether the occupants reached their desired (stated) goal during the shaking period. Not reaching a desired goal may leave a person vulnerable to earthquake hazards. 

Occupants actions after the period of shaking may place them in a low- or high-risk situation. Potential hazards may be loose or dislocated objects, or dangers from aftershocks. Unlike events during shaking, occupants have more time to interact with objects encountered in their paths after shaking 

has stopped. Range of difficulty for encounters and interactions may remain the same as before. The degree to which occupants have accomplished what they wanted to do after the shaking has stopped. Occupants may expose themselves to more hazards by setting low-priority 

goals and performing unnecessary activity in a hazardous building immediately after an earthquake. 

*Importance multiplier is a measure of the dependence between each item in the list and the occupant's exposure to potential hazards. 

minus 1 if the action performed by the person is a safe 

one. A factor of zero (neutral) is assigned to an action 

which is partially safe or does not contribute to a higher 

degree of hazard exposure. And a factor of 1 is assigned to 

an action that significantly increases the potential for hazard exposure. Numerical calculations were performed as 

follows. The initial reaction of each respondent was determined by our interview records. For example, let us assume that a person's reaction was to move a wheelchair 

under an overhead beam away from a glass window. This 

reaction was given a hazard weighting factor of minus 1. 

Similarly, hazard weighting factors were assigned to the 

remaining action sequences for this person. The resulting 

nine numerical values were then multiplied by their corresponding importance multipliers. Then, these values were 

summed giving the final numerical score of hazard exposure for each individual. The theoretical range of minimum to maximum possible total scores for each 

respondent was from minus 31 to plus 31 (larger positive 

numbers denote increasing hazard exposures). The 

summed total score for each of the 33 respondents was 

calculated and shown in figure 1. 

The total scores for our sample ranged from minus 28 to 

plus 28. A majority of the respondents (26 persons) fell in 

the negative score region, indicating overall safe perforrnance of their action sequences. From the seven responTable 8. Occupant risk analysis weighting factors 

Action list Hazard weighting factor * 

Initial reaction 

Observing the surroundings 

Decision for next action 

Protective actions during 

shaking 

Interaction with obstacles 

Reaching desired goal 

Protective actions after 

shaking stopped 

Interaction with objects 

Reaching desired goal 

Controlled motion 

Complete and objective 

Safe 

Safe 

No obstacles1 

no difficulty 

Reached 

Safe 

No obstacles/ 

no difficulty 

Reached 

Partially controlled 

Partially observant 

Somewhat safe 

Somewhat safe 

Some obstacles/ 

some difficulty 

Partially reached 

Somewhat safe 

Some obstacles/ 

some difficulty 

Partially reached 

Involuntary motion 

None 

Hazardous 

Hazardous 

Major difficulty 

Not reached 

Hazardous 

Major difficulty 

Not reached 

* Hazard is defined as conditions that can cause injury, illness, or death to occupants. 

dents having positive scores, only two persons had scores 

significantly above 20--indication of exposure to potential hazards in the earthquake. The behavior of the person 

with the highest score is explained in detail. 

Respondent 1, score=plus 28. The respondent was in his chair 

watching television. The initial reaction for this person was an 

involuntary spasm. The spasm left him vulnerable to the danger 

from falling heavy objects in a nearby closet, television falling 

and blocking access, and overhead ceiling fixtures. He was unable to control his wheelchair during the entire period of shaking 

until he received help from the outside. During the initial seconds of the shaking, he was unable to observe his surroundings 

and look for potential hazards. In addition, he did not recall making any judgment or decision to alter his situation. He, therefore, 

stayed in the same body position and location throughout the enRespondent Number 

Figure 1. Bar graph indicating the total hazard exposure scores for 33 

physically disabled occupants during the Loma Prieta earthquake. Note: 

Data were not communicated or completed for respondent 8. 
BUILDING CONTENT HAZARDS AND BEHAVIOR OF MOBILITY-RESTRICTED RESIDENTS 

tire shaking period. His major effort during the event was to control his spasms. He also tried to retrieve his mouth piece (a 

control device for wheelchair) that had shifted from its position. 

He was unsuccessful in both of these goals. This respondent was 

in this state until the institution staff made their rounds to insure 

that everyone was safe. 

In contrast, to show the behavioral profiles of occupants, 

the activities of the person with the lowest score is also 

elaborated. 

Respondent 20, score=minus 28. The respondent was working at 

his computer terminal at the onset of shaking. All of his actions 

during the shaking period were based on conscious and controlled thought processes. His initial reaction was to pull away 

from the terminal where there were heavy book shelves and a 

number of breakable items. He then made a thorough observation 

of his surroundings and moved under the main overhead beam. 

Once the shaking stopped, he headed for the main door and remained outside for awhile. His only possible hazardous activity 

was that he returned indoors to check the apartment for personal 

items while the potential for aftershocks existed. 

From our analysis of the 33 respondents, it appears that 

a consistent application of this methodology can provide a 

quantitative profile of occupant behavior in relation to 

earthquake hazard exposure inside buildings. Using the 

quantitative three-level weighting factor, this method is capable of accurately categorizing the respondents' action 

sequences in reference to a predetermined independent 

variable such as hazard exposure, age, gender, type of disability, type of interior design, or prior earthquake experience. However, a disadvantage of this method is the 

difficulty by which the degree of detail for actions needs 

to be predefined. For example, in the list of generic actions, the last action item was classed as "reaching the desired goal." In our sample, some respondents were able to 

specifically mention whether they were successful in performing what they specifically wanted to do during the period of shaking. In other cases, however, this item needed 

to be later inferred by the evaluator after long explanations 

were given by the respondents. Also, a certain degree of 

subjectivity is applied in assigning the weighting scores. 

For example, a person moving under a doorway may be 

assigned a safe score only if there is no door swinging 

violently by the shaking forces. Nevertheless, this technique allows us to combine a subjective evaluation of 

human interactions (including environmental variables inside a room) with an objective assessment of hazard exposure. Further refinement of this technique would be able to 

incorporate into a single chart factors that are difficult to 

quantify such as position and location of dangerous objects, type and weight of objects, height and projectile potential of items in proximity to the occupant, and 

organization of household items in relation to the interior 

design of the room. 

CONCLUSIONS 

It was noted that a significant portion of the public living in earthquake-prone regions is disabled. Like other 

victims, disabled persons may require assistance in a 

major earthquake. However, little is known at the present 

time about what the special needs of this population may 

be. For example, while some writers (see Pollander and 

Rund, 1989) state that simple and efficient training for 

self-protection and search and rescue procedures are needed to better assist disabled persons, others might argue that 

their needs in this regard are no different from those of the 

general population. Regardless, a significant emphasis has 

been placed on special populations in the U.S. Decade for 

Natural Disaster Reduction (National Research Council, 

1991): (1) to take an inventory of special-need groups and 

conduct hazard and risk assessments for vulnerable populations, (2) to educate and prepare elderly, disabled, and 

special needs groups by providing proper information 

and risk communication, and (3) to mitigate hazards by 

structural measures, nonstructural measures, and training 

programs. 

The literature suggests that the risk of earthquake-related 

death or injury inside residential buildings is multifaceted 

and complex. A number of factors may influence mortality 

and morbidity outcomes in earthquake situations. Focusing 

on the Loma Prieta earthquake, our study attempted to assess how exposed were disabled persons to potential hazards inside their dwellings and what they did to protect 

themselves during the shaking. This study involved a 

small sample of persons with physical disabilities affecting 

motor coordination and the functional loss of upper and 

lower extremities, who were living in mostly independent 

residential settings. The earthquake was of moderate to 

high intensity and did not cause any complete or partial 

collapse of structures in which respondents were located. 

Any generalization from this study, therefore, must take 

into account a large number of variables not considered in 

this study. 

There have been some clear indications that residential 

occupants show considerable variation in their actions during earthquake shaking (Ohashi and Ohta, 1984; Alexander, 1990). In the current study, results from the actioncontent analysis showed that the initial reaction at the onset of the shaking was critical to the individual's overall 

hazard exposure. Also, the decision actions that followed 

appeared to be significantly influenced by the initial reaction of the occupants. An example from our sample illustrates this point clearly. A respondent was in his 

wheelchair (battery-powered with inflatable tires) reading 

a book when he became aware of the seriousness of the 

event. He thought of moving toward the hallway to exit. 

He immediately reconsidered this move knowing the potential dangers of the broken items in the hallway. The 
B60 PUBLIC RESPONSE 

broken glass objects may have ruptured the wheelchair 

tires rendering him immobile during and after the earthquake--a potential trapping hazard. 

The idea that physically disabled individuals are more 

restricted than able-bodied persons, in the type and extent 

of activities they can initiate during and after earthquake 

impact, seems intuitive. However, our results appear to 

support the notion that the apparent lack of activity of disabled persons does not positively correlate with their feeling of vulnerability (fear of danger) during the shaking 

period. We noted that, of those who felt vulnerable (14 out 

of 33), more than two-thirds took active measures to protect themselves. In contrast, those who reported feeling little or no fear were more likely to remain passive during 

the shaking period. The self-protective actions of disabled 

persons appear to be closely related to their feeling (perception) of safety; those who feel safe apparently do not 

feel compelled to do anything more during earthquake impact to protect themselves. This finding seems to parallel 

to that of Goltz and others (1991) that an increasing level 

of fear "contributes to a definition of the situation as 

threatening to self and others and triggers certain learned 

responses which are survival-oriented." Our study also 

supports a position taken by some investigators that disabled persons have a psychological advantage for adapting 

to an altered built environment, since they negotiate with 

altered and sometimes difficult physical and environmental 

limitations on a daily basis (Parr, 1987; Tierney and others 

1988). Also, the respondents appeared to be very aware of 

their environmental make-up and were highly adapted to 

their disability (adaptive response) in relation to critical 

activities needed for their daily task performances. Given 

the dichotomy of the respondents' behaviors, it cannot be 

stipulated whether a passive or active mode of behavior 

provides a safer framework for dealing with earthquake 

hazards. 

Although there have been some rare cases where panic 

and flight were reported in earthquakes (see Alexander, 

1990), accounts of irrational behavior among the affected 

populations are less evident in the United States. In order 

to provide some data as to the nature of behavior exhibited 

in our sample, a more detailed analysis of their actions 

was conducted. Based on our action-content analysis, the 

majority of the respondents' sequence of activities included logical patterns of behavior during the shaking period. 

Only two respondents recalled entering into a state of uncontrolled spasmodic behavior. Based on our small sample 

observations, it is therefore suggested that disabled persons go through a somewhat logical and controlled behavioral process, perhaps more than previously expected. 

Similar results were obtained from a study of the Whittier 

Narrows earthquake in 1987, where the majority of the respondents (able-bodied) did not remain in place, yet they 

did not exhibit any irrational behavior (Goltz and others, 

1991). 

In comparison to general population, this pattern of 

mostly logical and controlled behavior of our sample is 

similar to that expressed by Ohta and Ohashi (1980) for an 

"able-bodied" sample. In their sample, the highest frequency of time-sequenced behavior was "action-movement-stand by" classification. In terms of application for 

this result, this may be another support for the importance 

of prior earthquake training and preparedness. Being prepared for appropriate occupant behavior, regardless of disability, would help occupants to behave more rationally 

and safely during an earthquake. A difficulty is the communication of such risks for earthquake preparedness 

among the disabled population. As Mileti and others 

(1990) explain, in order to take preventive and protective 

actions in earthquakes, the occupants must come to "own" 

the risk information. Only after they own the earthquake 

risk information do they take the advice they were given 

to prepare for it and to mitigate its effects. The practicality 

of earthquake preparedness recommendations should be in 

the direction of giving advice on things that can be done 

quickly without a significant amount of effort involved. It 

is equally important that such guidelines be based on empirical evidence targeted for this segment of the population 

rather than on speculation or generalization from the overall population. For example, advice such as moving under 

a sturdy table during the shaking period, may not be applicable to a T4 quadriplegic because of the fear of not being 

able to move back into the wheelchair. 

The results from this study also show that physically 

disabled persons may have less opportunity to access their 

personal items and emergency medical supplies after the 

shaking has stopped. A majority of the respondents who 

went back to their residences were unsuccessful in reaching and collecting what they needed. Planning and preparedness documents for disabled people should reflect 

alternative means by which the personal items and emergency supplies can be accessed. Also, the previously suggested "buddy system" (for example, a roommate or a 

neighbor helping the disabled individual) would not be effective if the occupant is living independently. Additionally, another observation from our sample was that many of 

the hazardous items were clustered around the beds or 

rest-chai~s. Obviously, these small items were positioned 

for convenience. Yet, from our observations, no attempt 

was made to either secure these items or reduce their injury-producing potential in time of a severe earthquake. 

Finally, it appears that the majority of respondents in our 

sample were not exposed to a high degree of danger during the earthquake. One field study on occupant behavior 

in earthquakes clearly suggests that injuries are more likely to occur when people try to leave the building or move 

around during earthquake shaking (Archea and Kobayashi, 

1984). If our findings are generalizable, mobility limitations would not necessarily make disabled individuals 

more vulnerable to injury. Furthermore, it may be that, 
BUILDING CONTENT HAZARDS AND BEHAVIOR OF MOBILITY-RESTRICTED RESIDENTS B61 

since disabled persons must cope with the physical environment on a daily basis, they will in fact be more adaptable to hazards in an altered environment than able-bodied 

persons. 

In light of the limitations of this study, our reported findings need to be reevaluated on much larger samples, comparing (different types of) disabled and able-bodied 

persons, and in both field studies and more controlled settings. Another factor not considered in this study is the 

fact that people with different types of disabilities may react differently at the onset of earthquakes. Also, studying 

behavior of disabled people in group settings (with potential expectation of help from others) would further add to 

our understanding of the needs of disabled individuals in 

earthquake situations. It is hoped that comparative studies 

in behavioral responses of "special populations" would 

eventually contribute to our understanding of how the general population can be further protected against the damaging effects of earthquakes. 

ACKNOWLEDGMENTS 

This research was supported by a grant from the National Science Foundation (BCS-8910457). Ms. Constance 

Holland helped us in interview scheduling and data collection. We appreciate the help we received from many organizations that give support to the disabled communities in 

northern California. Finally, thanks to the people who 

agreed to participate in this study. 

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

SOCIETAL RESPONSE 

PUBLIC RESPONSE 

EARTHQUAKE PREPAREDNESS BEHAVIOR OF STUDENTS AND 

NONSTUDENTS 

CONTENTS 

By John-Paul Mulilis and T. Shelley Duval, 

University of Southern California 

Page 

63 

63 

63 

64 

65 

67 

68 

68 

68 

ABSTRACT 

Individual earthquake preparedness and perceived difficulty of becoming prepared for earthquakes were assessed for two separate populations both before and after 

the Loma Prieta earthquake. One of the populations consisted of University of Southern California undergraduate 

students, and the other population was composed of employees (nonstudents) of a Long Beach, California, business firm. Results indicated that prior to the earthquake, 

nonstudents were more prepared than students. However, 

both groups perceived that preparing for earthquakes was 

equally difficult. Moreover, following the earthquake, both 

groups indicated an initial increase in preparedness behavior and a decrease in perceived difficulty of preparation. A 

comparison of these results with results obtained from 

similar studies appears to indicate that higher levels of 

damage due to earthquakes, in concert with other factors, 

can lead to increased perceived earthquake threat, which 

in turn can lead to increased attempts to cope with such 

events, resulting in increased earthquake preparedness. 

INTRODUCTION 

Over the past few years, earthquake preparedness behavior has become a topic of increasing worldwide importance 

(see Drabek, 1986; Morton, 1990; Quarantelli, 1989, for 

bibliographic reviews). Owing to the occurrence of large 

and numerous earthquakes, California in particular has become a recent focus of this topic as evidenced by several 

studies describing the effects of earthquakes in California 

(in particular, the 5.9 magnitude Whittier Narrows earthquake of October 1, 1987, the 4.8 magnitude Whittier Narrows earthquake of February 11, 1988, and the 5.5 

magnitude Upland earthquake of February 28, 1990) on individual earthquake preparedness behavior (Mulilis and Duval, 1990a, b; Mulilis and Duval, 1991b; Mulilis and others, 

1990). A somewhat unique aspect of these studies is that 

they were all of a pre-post nature; that is, levels of both 

earthquake preparedness and perceived difficulty of preparing for earthquakes were assessed both before and after the 

earthquakes occurred, thus allowing for the direct examination of the effects of the earthquakes on these variables. 

One of the few shortcomings of the above studies is that 

they were all conducted on a single type of population (undergraduate university students). The present study was designed to investigate the effects of the Loma Prieta 

earthquake on earthquake preparedness behavior, and at the 

same time, to attempt to overcome this single-population 

limitation by using two separate populations (students and 

nonstudents). Thus, direct comparisons of the effect of the 

same earthquake on earthquake preparedness behavior between two different populations could be made. On the 

basis of the results of the above studies, it was expected that 

the Loma Prieta earthquake would lead to increased earthquake preparedness and decreased perceived difficulty in 

preparing for earthquakes. Furthermore, the present study 

was designed to allow for a comparison of obtained results 

with the findings of the above studies to give a more complete understanding of the effects of earthquakes on earthquake preparedness behavior. 

EARTHQUAKE PREPAREDNESS SCALE 

The earthquake preparedness scale used in the present 

study was the MLEPS (Mulilis Lippa Earthquake Prepared- 
B64 PUBLIC RESPONSE 

ness Scale; Mulilis, 1985; Mulilis and Lippa, 1985; Mulilis 

and others, 1990), which was developed for use in assessing the earthquake preparedness and perceived difficulty in 

preparing for earthquakes of individuals and small businesses. The MLEPS is a multiact behavioral scale consisting of 27 preparedness items (for example, "DO you have 

an operating flashlight?', "Are your cabinets securely fastened with latches?', "DO you know the location of a medical emergency center in your neighborhood?') to which 

respondents answer "yes", "no", or "unsure" to each item. 

The 27 items of the MLEPS represent standard suggestions appearing in earthquake preparedness brochures and 

books that are specifically and clearly related to earthquake 

preparedness. These items not only measure how prepared 

one is over a wide range of preparedness, but also assess 

individual behavioral involvement in earthquake preparedness. Thus, the MLEPS is essentially a behavioral scale, 

and as such, the items in the scale have high face validity. 

Although behavioral in nature, the scale also allows for the 

consideration of an assessment of an individual's "cognitive preparedness.'' Turner and others (1 986) have stressed 

the importance of "cognitive preparedness," indicating that 

by being aware of the availability of items in a household 

(even though the items had not been newly acquired), individuals were in more of a position to use them. 

In addition to assessing level of preparedness, the 

MLEPS also assesses the difficulty in obtaining or performing each item on a scale of 1 (least difficult) to 5 (most 

difficult). The MLEPS has been used in a number of recent 

earthquake preparedness investigations (see Mulilis, 1985; 

Mulilis, 1991; Mulilis and Duval, 1987; Mulilis and Duval, 

1990a, b; Mulilis and Duval, 1991a, b; Mulilis and others, 

1990; Mulilis and Lippa, 1990). 

While Turner and others (1986) developed a 16-item 

"checklist of suggestions" for use in a study of the earthquake potential of the "Palmdale Bulge,'' the MLEPS 

measures more aspects of earthquake preparedness than the 

checklist and to the authors' knowledge, is the only preparedness scale that addresses the issue of difficulty in preparing for earthquakes. Furthermore, the major focus of the 

response format of the Turner and others (1986) checklist 

seems to involve reasons for carrying outhot carrying out 

preparedness actions. The present study, on the other hand, 

was more concerned with the overall extent to which a 

person was prepared for earthquakes and how difficult that 

person perceived preparing for earthquakes to be. Consequently, the MLEPS was used in the present investigation. 

POPULATIONS ASSESSED 

Two separate populations of subjects participated in the 

current investigation: students and nonstudents. Both of 

these populations were drawn from the greater Los Angeles area, approximately 488 km south of the epicenter of 

the Loma Prieta earthquake. Although not considered geographically local to Los Angeles, the Loma Prieta earthquake was widely felt throughout the Los Angeles area, 

produced immense destruction in the San Francisco Bay 

area, and received extensive and prolonged media coverage in the Los Angeles area. Thus, the direct effects of this 

earthquake were widely communicated in a credible manner to an area of similar earthquake risk and had many of 

the major components that have long been known to affect 

attitudes and behavior (see McGuire, 1969, 1985; Petty 

and Caccioppo, 1986; Fazzio, 1986; Ajzen, 1987; Chaiken 

and Stranger, 1987). Thus, the occurrence of this earthquake had the potential to influence attitudes and behaviors about earthquake preparedness and perceived 

difficulty of preparation for individuals living in the Los 

Angeles area, and any changes in preparedness behavior 

of the populations studied in the present investigation 

which were attributed to the Loma Prieta earthquake could 

be considered the result of this "nearby" (in a psychological sense) earthquake. 

The first population included in the present study consisted of undergraduate students enrolled in an introductory psychology course at the University of Southern 

California. Students volunteered for this study to obtain 

additional course credit. On Se9tember 20, 1989, all students enrolled in the course (approximately 410 students) 

were given a "survey packet" to complete for extra course 

credit. Approximately 71 percent of the students (292) returned the completed survey packet on September 25, 

1989, three weeks prior to the Loma Prieta earthquake. 

The MLEPS was included in this survey packet. 

After the earthquake, four separate groups of subjects 

were randomly sampled from the 292 students who had 

completed the survey packet. The MLEPS was then administered to each of these groups (once per group) at four 

different time periods after the earthquake (the day after, 

one week after, three weeks after, and six weeks after). A 

total of 99 subjects (four separate groups ranging in size 

from 17 to 35 subjects) completed the MLEPS after the 

earthquake. Demographic characteristics and relevant 

earthquake information of students who completed the 

pre-earthquake survey packets and subjects in the four 

groups who completed the MLEPS after the earthquake 

are presented in table 1. Since the number and characteristics for males and females were similar for all groups, 

these data are collapsed across gender. 

The following points can be noted from an investigation 

of table 1: 

(1) Demographic characteristics of the groups tested both 

before and after the earthquake were similar. 

(2) The student status of the four groups is evidenced by 

the large percentage of all groups who lived in dormitories, 

(3) Even though the number of months since an earthquake was experienced (following the Lorna Prieta earthquake) decreased for each of the groups tested the mean 
EARTHQUAKE PREPAmDNESS BEHAVIOR OF STUDENTS AND NONSTUDENTS 

Table 1 .-Characteristics of the student groups Table 2.-Characteristics of the nonstudent groups 

Variable 

Time relative to the Loma Prieta earthquake 

3 weeks 1 day 1 week 3 weeks 6 weeks 

before after afker dter aÂ£te 

Number 292 26 21 17 35 

Mean aee 18.6 19.0 18.9 19.3 19.1 

Mean years lived 

in California 9.6 9.4 12.1 10.5 9.2 

Largest 

earthquake felt 

(mean Richter) W.3 W.7 W.9 W.7 W.6 

Months since felt 

this earthquake 76.2 44.1 43.4 48.0 33.3 

Most recent 

earthquake felt 

(mean Richter) 63.1 W.1 W.1 63.9 M-3.8 

Months since felt 

this earthquake 59.7 37.0 24.4 31.5 19.3 

Residence (pct.): 

With parents 12.7 23.1 19.0 17.6 8.6 

With relatives 0.6 3.8 0.0 0.0 0.0 

Fraternity/sorority 6.2 0.0 9.5 5.9 0.0 

Dorm 41.8 30.8 28.6 47.1 51.4 

Rent 38.4 42.3 42.9 29.4 40.0 

own 0.3 0.0 0.0 0.0 0.0 

Number 18 

Mean age 32.9 

Mean years lived 22.2 

in California 

Residence (pct.): 

With parents 11.1 

With relatives 0.0 

Fraternity/sorority 0.0 

Dorms 0.0 Rent 33.3 

own 55.6 

Time relative to the Loma Prieta earthquake 

1 112 weeks 

Variable 1 day before after 

brgest 

earthquake felt 

(mean Richter) 66.2 Ih6.0 

Months since felt 

this earthquake 111.0 121.0 

Kost recent 

earthquake felt 

(mean Richter) W.4 W.6 

Noutb since felt 

thin earthquake 13.1 

reported values for all such groups were much greater than 

the actual time that had passed since the occurrence of this 

earthquake, indicating that these subjects probably did not 

actually experience any seismic effects of the Loma Prieta 

event. 

The second population included in the present study 

consisted of employees of a business firm in Long Beach, 

California (approximately 34 km from the University of 

Southern California). Subjects from this population volunteered for this study as part of the firm's earthquake preparedness program, which had been in existence for 

approximately 1 year prior to the present investigation. 

These subjects were randomly selected from a pool of approximately 40 employees and asked to complete the 

MLEPS as part of this program. All subjects in this population who were thus approached agreed to participate in 

this study. 

At the time of the Loma Prieta earthquake the firm employed approximately 40 employees. On October 6, 1989 

(approximately 1 112 weeks before the earthquake), 18 employees (45 percent) completed the MLEPS. On October 

10, 1989 (one day after the earthquake) these same 18 

employees again completed the MLFPS. Demographic 

characteristics and relevant data concerning subjects' experience involving the occurrence of earthquakes are presented in table 2. Because the number and characteristics 

of males and females were similar, these data were collapsed across gender. 

The following points are clear from an investigation of 

table 2: 

(1) The largest percentage of this group owned their 

dwellings. 

(2) The nonstudent status of the population is evidenced 

by the fact that no one in this group indicated that they 

lived in either dormitories or fraternitylsorority houses. In 

addition, higher mean ages were reported by this group 

compared with the mean ages for the groups in the student 

population (see table 1). 

(3) Again, as with the student population, even though 

the number of months since an earthquake was experienced decreased, the mean reported value of this group 

was much greater than the actual time which had passed 

since the occurrence of the Loma Prieta earthquake, indicating that these subjects did not actually experience any 

seismic effects of this earthquake. 

The following differences between the student and nonstudent populations can be noted from a comparison of tables 1 and 2: 

(1) The nonstudent group reported higher mean values 

of age, years lived in California, the largest magnitude 

earthquake which they had felt, and the most recent magnitude earthquake which they felt, indicating that this population may have had more "earthquake experience" than 

the student population. 

(2) The nonstudent group reported a lower mean time 

since they felt an earthquake, indicating that this population may be more cognizant or aware of the occurrence of 

the Loma Prieta earthquake and (or) of the occurrence of 

earthquakes in general. 

RESULTS 

Results of the present study are present in table 3 in 

terms of mean levels of earthquake preparedness and perceived difficulty in preparing for earthquakes as a function 

of time relative to the Lorna Prieta earthquake. Differences 

between males and females were minor and inconsistent. 
B66 PUBLIC RESPONSE 

Table 3.-Eflects of the Lorna Prieta earthquake on earthquake preparedness behavior 

Tim 

relative to 

LOM Prieta Mean levels of Mean levels of 

Population earthquake preparedness difficulty 

Students 3 weeks before 46.9 61.8 

1 day after 47.1 54.1 

1 week after 47.9 57.1 

3 weeks after 46.9 59.1 

6 weeks after 48.1 56.7 

Nonstudents 1 112 weeks before 55.8 61.8 1 day after 57.6 50.7 

Consequently, all analyses and comparisons were made 

collapsing the data across gender. 

The following points can be noted from an inspection of 

table 3: 

(1) Pre-earthquake levels of preparedness were significantly higher for nonstudents than for students (m=55.8 

vs. m=46.9, t(308)=3.69, pc0.001). Since there was a 

much higher percentage of homeowners in the pre-earthquake nonstudent group than in the pre-earthquake student group (55.6 vs. 0.3 percent), these results are 

consistent with results of Turner and others (1986), who 

found that owner-occupied households had higher rates of 

earthquake preparedness than did other types of households. Alternatively, the higher pre-earthquake preparedness levels of nonstudents could be attributed to 

differences in age or earthquake experience between the 

two groups. Interestingly enough, pre-earthquake levels of 

perceived difficulty in preparing for earthquakes were the 

same for both students and nonstudents (t(308)cl, n.s.). 

(2) Levels of perceived difficulty in preparing for earthquakes one day after the earthquake decreased from preearthquake levels for both students and nonstudents. This 

decrease in perceived difficulty was significantly lower 

than pre-earthquake levels for students (mz61.8 vs. 

m=54.1, t(3 16)=2.14, p=0.033) and approached significance for nonstudents (mz61.8 vs. m=50.7, t(37)=1.72, 

p=0.093). This initial decrease in perceived difficulty observed following the 7.1 magnitude Loma Prieta earthquake was consistent with the initial decrease in 

perceived difficulty observed in students following the 5.9 

magnitude Whittier Narrows earthquake of October 1, 

1987 (Mulilis and Duval, 1990a; Mulilis and others, 

1990). 

(3) The initial decrease in perceived difficulty one day 

after the earthquake was greater for nonstudents than for 

students (m=61.8 to m=50.7 vs. m=61.8 to m=54.1), although the difference in levels of perceived difficulty between the two groups one day after the earthquake was not 

significant (m=50.7 vs. m=54.1, t(45)=0.68, p=0.499). 

(4) Following the initial post-earthquake decrease, subsequent levels of perceived difficulty of preparation for 

students exhibited a distinct pattern. These levels continually increased through week three following the earthquake, then deceased through week six following the 

earthquake. This decrease at week six reached levels that 

approached a significant difference from pre-earthquake 

levels (m=56.7 vs. m=6 1.8, t(325)=1.62, p=O. 105). The 

distinct pattern in perceived difficulty of preparation following the 7.1 magnitude Loma Prieta earthquake was 

consistent with the distinct, although somewhat different, 

pattern of post-earthquake levels of perceived difficulty 

that was observed in students following the 5.9 magnitude 

Whittier Narrows earthquake of October 1, 1987 (Mulilis 

and Duval, 1990a; Mulilis and others, 1990); however, it 

was in contrast to the random fluctuations in perceived 

difficulty that were observed in students following both 

the 4.8 magnitude Whittier Narrows earthquake of February 11, 1988 (Mulilis and Duval, 1990b) and the 5.5 magnitude Upland earthquake of February 28, 1990 (Mulilis 

and Duval, 199 lb). 

(5) Levels of earthquake preparedness one day after the 

earthquake increased from pre-earthquake levels for both 

populations, although these increases did not reach levels 

of significance for either students (m=46.9 vs. m=47.1, 

t(3 16)=0.08, p=0.938) or nonstudents (mz55.8 vs. m=57.6, 

t(37)=0.62, p=0.541). This initial increase in preparedness 

observed in both students and nonstudents following the 

7.1 magnitude Loma Prieta earthquake was consistent with 

the significant initial increases in preparedness observed in 

students following the 5.9 magnitude Whittier Narrows 

earthquake of October 1, 1987 (Mulilis and Duval, 1990a; 

Mulilis and others, 1990). 

(6) As was the case for pre-earthquake levels of preparedness, initial levels of preparedness one day following 

the earthquake were significantly greater for nonstudents 

than for students (mz57.6 vs. m=47.1, t(45)=3.9 1, 

~~0.001). Since there was a much higher percentage of 

homeowners in the post-earthquake nonstudent group than 

in the post-earthquake student group one day after the 

earthquake (38.1 vs. 0.0 percent), these results are again 

consistent with results of Turner and others (1986), who 

found that owner-occupied households had higher rates of 

earthquake preparedness than did other types of households, although again, these results could be attributed to 

differences in age or earthquake experience between the 

two groups. 

(7) Following the initial post-earthquake increase, subsequent levels of preparedness for students exhibited a distinct pattern. These levels increased through week one 

following the earthquake, then decreased to pre-earthquake 

levels at week three following the earthquake, and then 

subsequently increased through week six following the 

earthquake. This distinct pattern of post-earthquake preparedness levels observed in students following the 7.1 

magnitude Loma Prieta earthquake was consistent with the 

distinct pattern of post-earthquake levels of preparedness 

observed in students following the 5.9 magnitude Whittier 

Narrows earthquake of October 1, 1987 (Mulilis and Duval, 1990a; Mulilis and others, 1990); however, it was in 
EARTHQUAKE PREPAREDNESS BEHAVIOR OF STUDENTS AND NONSTUDENTS B67 

contrast to the random fluctuations in post-earthquake levels of preparedness observed in students following both 

the 4.8 magnitude Whittier Narrows earthquake of February 11, 1988 (Mulilis and Duval, 1990b) and 5.5 magnitude Upland earthquake of February 28, 1990 (Mulilis and 

Duval, 199 lb). 

DISCUSSION 

The above results appear to indicate that the 7.1 magnitude Loma Prieta earthquake affected the earthquake preparedness behavior of both student and nonstudent 

populations in a similar manner (initial significant decreases in perceived difficulty in preparing for earthquakes and 

initial increases in earthquake preparedness) and that these 

changes in earthquake preparedness behavior were similar 

to significant changes observed in the preparedness behavior of students following the 5.9 magnitude Whittier Narrows earthquake of October 1, 1987 (Mulilis and Duval, 

1990a; Mulilis and others, 1990). Although post-earthquake levels of perceived difficulty of preparation were 

significantly lower than pre-earthquake levels for subjects 

after both the 7.1 magnitude Loma Prieta and 1987 5.9 

magnitude Whittier Narrows earthquakes, post-earthquake 

levels of earthquake preparedness were significantly higher than pre-earthquake levels only for the 1987 5.9 magnitude Whittier Narrows earthquake. The fact that postearthquake increases in earthquake preparedness following 

the 7.1 magnitude Loma Prieta earthquake did not reach 

significance may have been due to the greater epicentral 

distance of this earthquake- from Los Angeles than the 

1987 5.9 magnitude Whittier Narrows earthquake (approximately 488 km vs. approximately 15 km). 

Furthermore, post-earthquake levels of earthquhke preparedness and perceived difficulty of preparation observed 

in student groups after the 7.1 magnitude Loma Prieta 

earthquake exhibited distinct patterns that were similar to 

the distinct patterns observed for these variables in students following the 1987 5.9 magnitude Whittier Narrows 

earthquake (Mulilis and Duval, 1990a; Mulilis and others 

1990) but distinctly different from the random fluctuations 

in these variables observed in students following both the 

1988 4.8 magnitude Whittier Narrows earthquake (Mulilis 

and Duval, 1990b) and the 1990 5.5 magnitude Upland 

earthquake (Mulilis and Duval, 199 1 b). Slight differences 

in the patterns of earthquake preparedness and perceived 

difficulty of preparation observed in subjects following the 

7.1 magnitude Loma Prieta and 1987 5.9 magnitude Whittier Narrows earthquakes may have been due to the greater 

epicentral distance of the Loma Prieta earthquake from 

Los Angeles, and (or) the larger and more numerous aftershocks produced by the Lorna Prieta earthquake. 

Thus, although the student populations in the studies of 

the above four earthquakes had similar pre-earthquake levels of earthquake preparedness and perceived difficulty of 

preparation (Mulilis and Duval, 1991a) and the demographic characteristics of these populations were similar 

(Mulilis and Duval, 1991a), levels of earthquake preparedness and perceived difficulty of preparation had quite different patterns after these earthquakes. These differences 

were observed despite the fact that data from all four 

earthquakes were collected in the same location and under 

similar circumstances. 

Differences in the impact of the four earthquakes on 

earthquake preparedness might be explained by important 

seismological differences between the earthquakes. Both 

the 1987 5.9 magnitude Whittier Narrows and 7.1 magnitude Loma Prieta earthquakes occurred at deeper focal 

depths, had greater Richter magnitudes, higher maximum 

surface accelerations, larger maximum modified Mercalli 

intensities, and were followed by larger and more numerous aftershocks than either the 1988 4.8 magnitude Whittier Narrows or 1990 5.5 magnitude Upland earthquakes 

(see Mulilis and Duval, 199 la). These seismological differences between the four earthquakes, in turn, resulted 

in greater damage from the 7.1 magnitude Loma Prieta 

and 1987 5.9 magnitude Whittier Narrows earthquakes 

than either of the other two earthquakes (Davis, oral 

commun., 199 1 ; Earthquake Engineering Research Institute, 1989, 1990; Federal Emergency Management Agency, 1987; Piore and Bucy, 1988; Jephcott, 1990; Tierney, 

1988; U.S. Geological Survey, 1989; Ward and Page, 

1989; table 4 provides a comparison of deaths, injuries, 

and property damage caused by these four earthquakes). 

We suggest that this greater level of damage from the 7.1 

magnitude Loma Prieta and 1987 5.9 magnitude Whittier 

Narrows earthquakes, in concert with other factors such 

as level of media coverage, distance from the epicenter, 

extent to which socially significant others were affected 

by earthquakes, and so forth, may have increased subjects' perceived threat due to earthquakes. As indicated 

by Lazarus (1 966) and Lazarus and Folkman (1984), increased perceived threat can lead to increased attempts to 

cope with the threatening event. In the present case, increased coping attempts could lead to increased earthquake preparedness behavior. In fact, laboratory studies 

by Mulilis and Duval (unpub. data, 1992) have found 

that increasing the perceived threat value of earthquakes 

does lead to increased earthquake preparedness behavior, 

but only under certain conditions. Thus, subjects may 

have increased their attempts to cope with earthquakes 

after the more threatening 7.1 magnitude Loma Prieta 

and 1987 5.9 magnitude Whittier Narrows earthquakes, 

which may have been manifested in increased earthquake 

preparedness behavior, whereas the less threatening 1990 

5.5 magnitude Upland and 1988 4.8 magnitude Whittier 

Narrows earthquakes induced no such changes in sub- I 

jects' coping attempts and consequently no increases in 

their earthquake preparedness behavior (Mulilis and Du- 
B68 PUBLIC RESPONSE 

Table 4.-Damaging efects of the case-study earthquakes 

Earthquake 

4.8Uhittier 5.5 5.9 Uhittier 7.1 LOVariable Narrows Upland Narrows Prieta 

batha 1 none 3 62 (heart attack) 

Injuries 32 35 932 3,757 (minor) (minor) 

Property 

age 

(million8 

of dollars) minor 10 350 6,000 

s-ry of 

age little som much great 

val, 1990a, b, 1991; Mulilis and others, 1990; table 5 

summarizes the effects of earthquake damage on earthquake preparedness behavior for these four earthquakes). 

Further research is needed to clarify this hypothesized 

explanation of changes in earthquake preparedness behavior after earthquakes. 

CONCLUSIONS 

Levels of earthquake preparedness and perceived difficulty in preparing for earthquakes wefe obtained from 

groups of both students and nonstudents in the greater 

Los Angeles area both before and after the Loma Prieta 

earthquake. Results of analyses on these data indicated 

that levels of earthquake preparedness observed in the 

nonstudent groups were significantly greater than levels 

of earthquake preparedness observed in student groups 

both before and after the Loma Prieta earthquake. Furthermore, levels of earthquake preparedness observed in 

both student and nonstudent groups prior to the Loma 

Prieta earthquake increased after the occurrence of the 

earthquake. These increases in earthquake preparedness 

after the 7.1 magnitude Loma Prieta earthquake, although 

not significant, were consistent with similar increases in 

earthquake preparedness after the 1987 5.9 magnitude 

Whittier Narrows earthquake. Furthermore, although differences in perceived difficulty of preparation between 

student and nonstudent groups were not significantly different either before or after the earthquake, comparisons 

of pre- and post-earthquake data revealed a significant 

decrease in perceived difficulty of preparation after the 

earthquake for the student groups, and a decrease in perceived difficulty of preparation which approached significance for the nonstudent group. These decreases were 

consistent with significant decreases in perceived difficulty of preparation observed in student groups following 

the 1987 5.9 magnitude Whittier Narrows earthquake. 

Additionally, post-earthquake levels of both earthquake 

preparedness and perceived difficulty in preparing for 

earthquakes observed in the student groups showed a disTable 5.-Efect of earthquake damage on earthquake preparedness behavior 

Earthquake 

4.8Whittier 5.5 5.9 Uhittier 7.1 Loma 

Earthquake Narrows Upland Narrows Prieta 

Epicentral 

distance from 

LOs Angeles 15 68 15 488 

03) 

Damage little some much great 

EÂ£Â£e on 

preparedness no no Yes s OM 

Effect on 

difficulty no no Yes Yes 

tinct pattern after the 7.1 magnitude Loma Prieta earthquake. These results were consistent with distinct 

patterns of these variables observed in similar student 

groups after the damaging 1987 5.9 magnitude Whittier 

Narrows earthquake, and in contrast to random fluctuations in these variables observed in similar student 

groups following lower magnitude, less damaging California e&thquakes. It was hypothesized that the level of 

damage caused by an earthquake, in concert with other 

factors, is a critical variable in determining induced perceived threat due to earthquakes, which under certain 

conditions can lead to increased attempts to cope with 

threatening earthquakes, resulting in increased earthquake 

preparedness behavior. 

Questions for further research include: (1) What variables associated with earthquakes lead to changes in induced perceived threat due to earthquakes? (2) How can 

perceived threat due to earthquakes be measured effectively? (3) Under what conditions does perceived threat 

due to earthquakes lead to increased attempts to cope 

with threatening earthquakes and subsequent increased 

earthquake preparedness behavior? 

Preparation of this paper was supported in part by National Science Foundation grant number BCS-89 1 17 15 to 

T. Shelley Duval and John-Paul Mulilis. 

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