U.S. Department of the Interior

U.S. Geological Survey

Scientific Investigations Report 2012–5222

Community Exposure to Tsunami Hazards in California

Prepared in cooperation with the California Emergency Management Agency and the California Geological Survey
FRONT COVER

Photographs of Crescent City (upper left), Huntington Beach (upper right), Alameda (lower left) and the Port of 

Long Beach (lower right) on the California coast shown with the internationally adopted tsunami-evacuation sign 

(Intergovernmental Oceanographic Commission, 2002). Photographs of the Port of Long Beach and Crescent City are 

reprinted with permission from Adelman and Adelman (2010). Aerial photograph of Alameda Island (image ID: AHLB3931) 

is courtesy of aerialarchives.com. Huntington Beach is from the City of Huntington Beach (2012), which states that all of 

its Web site content is public information.
Community Exposure to Tsunami Hazards 

in California

By Nathan J. Wood, Jamie Ratliff, and Jeff Peters

Prepared in cooperation with the California Emergency Management Agency 

and the California Geological Survey

Scientific Investigations Report 2012–5222

U.S. Department of the Interior

U.S. Geological Survey
U.S. Department of the Interior

KEN SALAZAR, Secretary

U.S. Geological Survey

Suzette M. Kimball, Acting Director

U.S. Geological Survey, Reston, Virginia: 2013

For more information on the USGS—the Federal source for science about the Earth, its natural and living resources, 

natural hazards, and the environment—visit http://www.usgs.gov or call 1–888–ASK–USGS

For an overview of USGS information products, including maps, imagery, and publications, 

visit http://www.usgs.gov/pubprod

Suggested citation:

Wood, N., Ratliff, J., and Peters, J., 2013, Community exposure to tsunami hazards in California: 

U.S. Geological Survey Scientific Investigations Report 2012–5222, 49 p.

Any use of trade, product, or firm names is for descriptive purposes only and does not imply 

endorsement by the U.S. Government.

Although this information product, for the most part, is in the public domain, it also may contain copyrighted materials 

as noted in the text. Permission to reproduce copyrighted items must be secured from the copyright owner.
iii

Contents

Abstract...........................................................................................................................................................1

Introduction.....................................................................................................................................................1

Purpose and Scope ......................................................................................................................................4

Study Area.......................................................................................................................................................4

Variations in Community Exposure .............................................................................................................6

Land Cover.............................................................................................................................................7

Residents................................................................................................................................................9

Employees............................................................................................................................................21

Community-Support Businesses......................................................................................................30

Dependent-Care Facilities ................................................................................................................31

Public Venues......................................................................................................................................34

Park and Beach Visitors ....................................................................................................................34

Composite Indices of Community Exposure............................................................................................38

Conclusions...................................................................................................................................................43

Acknowledgments.......................................................................................................................................43

References Cited..........................................................................................................................................44

Appendixes ...................................................................................................................................................47

Figures

 1. Photographs of tsunami-prone areas of California ........................................................................3

 2. Map of counties and incorporated cities with land in the California tsunami-inundation 

zone and coastline segments with mapped tsunami-inundation zones..............................4

 3. Maps of the tsunami-inundation zone and land-cover data from the 2006 National Land 

Cover Database for the communities of Crescent City, Eureka, Belvedere, Alameda, 

and Long Beach, California.........................................................................................................8

 4. Pie chart showing distribution of National Land Cover Database classes (by area)

 in the California tsunami-inundation zone...............................................................................9

 5. Plot showing amount of land by National Land Cover Database class 

in the tsunami-inundation zone of California coastal counties.............................................9

 6. Plots showing amount and percentage of developed land 

in the California tsunami-inundation zone..............................................................................10

 7. Plots showing number and percentage of residents 

in the California tsunami-inundation zone..............................................................................12

 8. Plot showing percentage of residents in the California tsunami-inundation zone 

that identify themselves as Hispanic or Latino......................................................................15

 9. Plot showing percentage of residents in the California tsunami-inundation zone 

that identify themselves as Asian ............................................................................................17

10. Plot showing percentage of residents in the California tsunami-inundation zone 

that are less than 5 years in age ..............................................................................................18

11. Plot showing percentage of residents in the California tsunami-inundation zone 
iv

that are more than 65 years in age ..........................................................................................19

12. Plot showing percentage of occupied households in the California 

tsunami-inundation zone that are renter occupied........................................................................20

13. Plot showing percentage of occupied households in the California 

tsunami-inundation zone that are headed by females with children 

less than 18 years in age and no spouse present.................................................................22

14. Photographs of examples of group quarters.................................................................................23

15. Plot showing percentage of residents in the California tsunami-inundation zone 

that are in institutionalized group quarters.............................................................................................24

16. Plot showing percentage of residents in the California tsunami-inundation zone 

that are in noninstitutionalized group quarters .......................................................................................25

17. Plots showing number and percentage of employees 

in the California tsunami-inundation zone..............................................................................26

18. Plot showing percentage of employees, by business sector, 

in the California tsunami-inundation zone..............................................................................28

19. Plot showing percentage of employees at businesses 

in the California tsunami-inundation zone with low and high visitor potential ................29

20. Plot showing number of community-support businesses and organizations

 in the California tsunami-inundation zone.............................................................................32

21. Plot showing number of dependent-population facilities 

in the California tsunami-inundation zone..............................................................................33

22. Plot showing number of public venues in the California tsunami-inundation zone................35

23. Photograph of Avalon Harbor on Catalina Island, California......................................................36

24. Photographs of recreationists in tsunami-hazard zones.............................................................36

25. Plot showing annual average number of visitors (in millions) to coastal California 

city and county beaches, State parks, and National Park Service locations 

grouped by city and county jurisdictions................................................................................37

26. Plot comparing normalized indices for the amount and percentage of community 

assets for communities with land in the California tsunami-inundation zone................... 39

27. Frequency histogram of the sum of normalized exposure indices for communities

in the California tsunami-inundation zone....................................................................................40

28. Plot showing sum of normalized amount and percentage indices for communities 

with land in the California tsunami-inundation zone ............................................................41

29. Photographs of communities considered to have high relative exposure to tsunamis .........42

Tables

1. Block-level demographic characteristics for residential populations in the California 

tsunami-inundation zone, based on the 2010 U.S. Census ..................................................14

2. Amount and percentage of businesses in the tsunami-inundation zone of California.............31

Appendix 1. Table of predicted tsunami run-up heights and primary sources for 

selected locations on the California coast.............................................................................48

Appendix 2. Attendance for various city and county, State, 

and national beaches and parks..............................................................................................49
Community Exposure to Tsunami Hazards in California

By Nathan Wood, Jamie Ratliff, and Jeff Peters

Abstract

Evidence of past events and modeling of potential events 

suggest that tsunamis are significant threats to low-lying 

communities on the California coast. To reduce potential 

impacts of future tsunamis, officials need to understand 

how communities are vulnerable to tsunamis and where 

targeted outreach, preparedness, and mitigation efforts may 

be warranted. Although a maximum tsunami-inundation 

zone based on multiple sources has been developed for the 

California coast, the populations and businesses in this zone 

have not been documented in a comprehensive way. To 

support tsunami preparedness and risk-reduction planning 

in California, this study documents the variations among 

coastal communities in the amounts, types, and percentages 

of developed land, human populations, and businesses in the 

maximum tsunami-inundation zone. 

The tsunami-inundation zone includes land in 94 

incorporated cities, 83 unincorporated communities, and 20 

counties on the California coast. According to 2010 U.S. Census 

Bureau data, this tsunami-inundation zone contains 267,347

residents (1 percent of the 20-county resident population), of 

which 13 percent identify themselves as Hispanic or Latino, 14 

percent identify themselves as Asian, 16 percent are more than 

65 years in age, 12 percent live in unincorporated areas, and 51 

percent of the households are renter occupied. Demographic 

attributes related to age, race, ethnicity, and household status 

of residents in tsunami-prone areas demonstrate substantial 

range among communities that exceed these regional averages. 

The tsunami-inundation zone in several communities also 

has high numbers of residents in institutionalized and 

noninstitutionalized group quarters (for example, correctional 

facilities and military housing, respectively). Communities with 

relatively high values in the various demographic categories are 

identified throughout the report.

The tsunami-inundation zone contains significant 

nonresidential populations based on 2011 economic data 

from Infogroup (2011), including 168,565 employees (2 

percent of the 20-county labor force) at 15,335 businesses that 

generate approximately $30 billion in annual sales. Although 

the regional percentage of at-risk employees is low, certain 

communities, such as Belvedere, Alameda, and Crescent City, 

have high percentages of their local workforce in the tsunamiinundation zone. Employees in the tsunami-inundation zone 

are primarily in businesses associated with tourism (for 

example, accommodations, food services, and retail trade) 

and shipping (for example, transportation and warehousing, 

manufacturing, and wholesale trade), although the dominance 

of these sectors varies substantially among the 94 cities. 

Although the number of occupants is not known for 

each site, the tsunami-inundation zone contains numerous 

dependent-population facilities, such as schools and child 

daycare centers, which may have individuals with limited 

mobility. The tsunami-inundation zone includes a substantial 

number of facilities that provide community services, such as 

banks, religious organizations, and grocery stores, where local 

residents may be unaware of evacuation procedures if previous 

awareness efforts focused on home preparedness. There are 

also numerous recreational areas in the tsunami-inundation 

zone, such as amusement parks, marinas, city and county 

beaches, and State and national parks, which attract visitors 

who may not be aware of tsunami hazards or evacuation 

procedures. During peak summer months, estimated daily 

attendance at city and county beaches can be approximately 

six times larger than the total number of residents in the 

tsunami-inundation zone. 

Community exposure to tsunamis in California varies 

considerably—some communities may experience great 

losses that reflect only a small part of their community 

and others may experience relatively small losses that 

devastate them. Among 94 incorporated communities and the 

remaining unincorporated areas of the 20 coastal counties, 

the communities of Alameda, Oakland, Long Beach, Los 

Angeles, Huntington Beach, and San Diego have the highest 

number of people and businesses in the tsunami-inundation 

zone. The communities of Belvedere, Alameda, Crescent 

City, Emeryville, Seal Beach, and Sausalito have the highest 

percentages of people and businesses in this zone. On the 

basis of a composite index, the cities of Alameda, Belvedere, 

Crescent City, Emeryville, Oakland, and Long Beach have the 

highest combinations of the number and percentage of people 

and businesses in tsunami-prone areas.

Introduction

The tragic loss of life and property damage associated 

with recent catastrophic tsunamis (for example, 2004 Indian 

Ocean, 2009 Samoa, 2010 Chile, 2010 Sumatra, and 2011 

Japan) has raised global awareness of tsunami hazards. 

Historical and geologic evidence indicate that the California 

coast has experienced similar large-magnitude tsunamis 
2 Community Exposure to Tsunami Hazards in California

and is likely to experience more. As described in greater 

detail by Wilson and others (2008) and Barberopoulou 

and others (2009), the California coast is susceptible to 

tsunamis generated by multiple sources, including far-field 

earthquakes, local earthquakes, and local landslides.

Far-field tsunami sources relate to earthquakes 

generated at long distances elsewhere on the seismically 

active Pacific Ocean margin. Recent examples include 

tsunamis associated with the 2011 magnitude 9.0 Tohoku 

earthquake in Japan (U.S. Geological Survey, 2011), the 

2010 magnitude 8.8 earthquake off of the southern coast of 

Chile, and the 1964 magnitude 9.2 earthquake in the eastern 

Aleutian-Alaska Subduction Zone (National Geophysical 

Data Center, 2012). In each case, the California coast 

experienced a series of damaging tsunami waves several 

hours after the far-field earthquake—approximately 4 hours 

in the 1964 event and more than 10 hours for the Tohoku 

and Chilean events (Lander and others, 1993; Wilson and 

others, in press). Loss of life has been low from recent farfield events because of the large amount of time between 

the earthquake and the wave arrival, as well as the existence 

of federal tsunami-warning centers that transmit alerts of 

incoming waves. Therefore, far-field tsunamis primarily 

represent economic threats related to damage to ports and 

harbors (National Geophysical Data Center, 2012; National 

Research Council, 2011). 

Tsunamis that impact the California coast can also be 

created by local earthquake sources, such as faults that cause 

vertical displacement of the seafloor. For communities on the 

northern California coast, the most significant local tsunami 

threat is associated with earthquakes emanating from the 

Cascadia Subduction Zone (CSZ), the interface of the North 

America and Juan de Fuca tectonic plates that extends more 

than 1,000 kilometers (approximately 621 miles) from Cape 

Mendocino in northern California to Vancouver Island, 

British Columbia, in Canada (Rogers and others, 1996). On 

the basis of geologic evidence, the CSZ has ruptured and 

created tsunamis at least seven times in the past 3,500 years 

and has a considerable range in recurrence intervals, from 

as little as 140 years between events to more than 1,000 

years (Atwater and others, 1995; Atwater and HemphillHaley, 1997; Goldfinger and others, 2003). The last CSZrelated earthquake is believed to have occurred on January 

26, 1700 (Satake and others, 1996; Atwater and others, 

2005). In addition to subjecting northern Californian coastal 

communities to intense ground shaking and liquefaction of 

unconsolidated sediments, a future CSZ-related earthquake 

(likely magnitude 8 or larger) would create a series of 

tsunami waves possibly 8 meters (approximately 26 feet) 

or higher that would inundate these communities in 15 to 

20 minutes after initial ground shaking (Uslu and others, 

2007; Cascadia Region Earthquake Workgroup, 2005; Geist, 

2005). Southern California communities would experience 

the Cascadia-related tsunamis in a far-field capacity, meaning 

they would not experience the ground shaking, and waves 

would arrive approximately 1 hour later. Additional examples 

of local earthquake sources in southern California include 

the Catalina, Newport Inglewood, and Channel Islands thrust 

faults (Barberopoulou and others, 2009).

Local landslides can also generate tsunamis due to 

the water displacement caused by the force of the subaerial 

or submarine movement of land. Landslides are most 

commonly triggered by earthquakes, but extremely low tides 

or construction in ports or harbors can also cause underwater 

slope failure. Submarine landslides are particularly dangerous 

in that they seldom offer much warning, making pretsunami 

preparation and evacuation difficult (Suleimani and others, 

2009). Tsunamigenic landslide sources include areas near 

Goleta, Palos Verdes, and Monterey Canyon, although 

researchers believe more investigations are needed to fully 

understand landslide-induced tsunamis and their impact on 

the California coast (Barberopoulou and others, 2009). 

Much has been done in California to prepare at-risk 

communities for future tsunamis by various entities in 

the public, private, and voluntary sectors. The California 

Emergency Management Agency (CalEMA) and California 

Geological Survey (CGS) have coordinated preparedness 

efforts in the State. Initial efforts have focused on describing 

the potential for future events, such as inundation modeling 

(Barberopoulou and others, 2009) and inundation maps 

(California Geological Survey, 2012). Preparedness efforts 

have focused on educating at-risk individuals about potential 

tsunami threats through such means as educational materials 

(Humboldt Earthquake Education Center, 2011), hazard signs, 

evacuation planning, training and exercises for emergency 

managers, tests of the warning system, and focused outreach 

campaigns (California Emergency Management Agency, 

2012). Educating individuals in areas prone to near-field 

tsunami threats is especially important because they will need 

to self-evacuate given the short amount of time available 

for evacuations (approximately 15 to 20 minutes) and the 

inability of public-safety officials to be everywhere at once 

(National Research Council, 2011). Federal tsunami-warning 

centers and a network of deep-ocean detection stations have 

been established to warn coastal communities of imminent 

tsunamis, particularly those generated by far-field sources 

(National Weather Service, 2012a). Programs have been 

created to promote and increase community resilience to 

tsunamis (National Weather Service, 2012b). 

Although much has been done to improve understanding 

of tsunami hazards and to raise general awareness of the 

need to prepare, less has been done to communicate how 

communities are specifically vulnerable to these hazards 

and how this vulnerability can vary within communities 

due to pre-existing societal conditions (U.S. Government 

Accountability Office, 2006; National Research Council, 

2011). Community vulnerability is defined here as the 

attributes of a human-environmental system that increase the 

potential for hazard-related losses or reduced performance 

during and after a catastrophic event. Vulnerability is 

influenced by how communities use hazard-prone areas, 

and along the California coast, occupation and use of 
Introduction 3

Figure 1. Photographs of tsunami-prone areas of California at (A) Inglenook, (B) Monterey, (C) Long Beach Marina, (D) a powerplant 

in Morro Bay, (E) Malibu, (F) Port of Long Beach, (G) Crystal Cove State Beach, and (H) the Santa Cruz Beach Boardwalk (images from 

Adelman and Adelman, 2010, used with permission). Photographs of examples of other types of land uses in tsunami-prone areas are in 

figures 14, 23, 24, and 29.

A

D

E

G

C

F

B

H
4 Community Exposure to Tsunami Hazards in California

tsunami-prone areas varies considerably, such as rural 

residential development (fig. 1A), mixed commercial and 

residential (fig. 1B), marinas (fig. 1C), industrial sites 

(fig. 1D), high-density residential development (fig. 1E), 

commercial ports (fig. 1F), recreational beaches (fig. 1G), 

and high-volume tourist boardwalks (fig. 1H). These land-use 

variations influence each community’s vulnerability, typically 

characterized by the exposure, sensitivity, and adaptive 

capacity of a community and its assets in relation to potential 

tsunamis (Turner and others, 2003). Exposure is a function of 

the proximity of populations and assets to hazards, whereas 

sensitivity and adaptive capacity are internal characteristics 

of an individual, group, or socioeconomic system that 

influence their ability to reduce their vulnerability. A tsunami 

may cause damage to buildings or injure people, but the 

cumulative choices a community makes with regards to its 

use of hazard-prone areas and its willingness to develop riskreduction strategies (for example, education programs and 

evacuation training) before an extreme event occurs set the 

stage for and will determine the extent of these losses (Mileti, 

1999; Wisner and others, 2004). 

To better understand societal vulnerability to California 

tsunami hazards, the California Emergency Management 

Agency (CalEMA) and California Geological Survey (CGS) 

sought assistance from the U.S. Geological Survey (USGS) 

to determine the number and type of people and businesses 

that are in tsunami-prone areas and how communities 

vary in their exposure to tsunami hazards. A maximum 

tsunami-inundation zone has been developed based on 

data from multiple sources (Barberopoulou and others, 

2009), and CalEMA and CGS were interested in knowing 

what populations and businesses were in these areas. 

Understanding how communities vary in their exposure to 

tsunamis helps emergency managers, land-use planners, 

public works managers, and the maritime community 

understand potential tsunami impacts and to determine where 

to complement regional risk-reduction strategies with sitespecific efforts that are tailored to local conditions and needs 

(for example, targeted education programs and evacuation 

procedures for specific schools or assisted-living facilities). 

Results can also be used to help prioritize preparedness 

funding, sites or sectors for mitigation cost-benefit analysis, 

and locations to develop next-generation hazard modeling, 

such as probabilistic tsunami hazard analysis.

Purpose and Scope 

This report documents geographic variations in 

community exposure to tsunami hazards in California. 

Community exposure is described by the amount and relative 

percentage of various populations and population-related 

indicators in tsunami-prone areas as defined by a maximum 

tsunami-inundation zone. Variations in community exposure 

to tsunamis are based on the presence of populations and 

businesses in tsunami-prone areas using regional datasets 

and tallied using geographic-information-system (GIS) tools; 

results are not engineering-based loss estimates for any 

particular facility. These inventories cannot be considered 

estimates of potential losses because aspects of individual 

perceptions and preparedness levels before a tsunami, 

adaptive capacity of a community during a response, and 

long-term resilience of individuals and communities after 

an event are excluded from this analysis (Pelling, 2002; 

Turner and others, 2003). Potential losses would only match 

reported inventories if all residents, employees, and visitors 

in tsunami-prone areas were unaware of tsunami risks, were 

unaware of what to do if warned of an imminent threat 

(either by natural cues or official announcements), and failed 

to take protective measures to evacuate. This assumption 

is unrealistic, given the current level of tsunami-awareness 

efforts in California (California Emergency Management 

Agency, 2012; National Weather Service, 2012b). Finally, 

the primary purpose of this population-exposure inventory 

is to support preparedness and education efforts; therefore, 

it does not include analysis of direct or indirect economic 

losses to individuals, businesses, communities, or to 

the regional economy (for example, lost revenues for a 

manufacturer because a supplier’s facilities were destroyed by 

a tsunami). This analysis is intended to serve as a foundation 

for additional risk-related studies and to help community 

members and local, State, and Federal policymakers (for 

example, in the emergency-management or land-use arenas) 

in their efforts to develop and prioritize preparedness and 

risk-reduction strategies that are tailored to local needs.

Study Area

This study of community exposure to tsunami hazards 

focuses on the 94 cities and 20 California counties that 

intersect a maximum tsunami-inundation zone (fig. 2). 

Incorporated cities and counties are delineated by 2010 

boundaries of the U.S. Census Bureau (U.S. Census Bureau, 

2010). These coastal counties also contain 83 unincorporated 

towns and villages, as delineated by census-designatedplace boundaries, which intersect the tsunami-inundation 

zone. Because emergency services, economic development, 

and land-use planning for the unincorporated towns and 

villages are performed by county offices, results related 

to these places and other county land not in incorporated 

Figure 2. A, Map of counties and incorporated cities with land 

in the California tsunami-inundation zone and coastline segments 

with mapped tsunami-inundation zones. B, Enlargement of the San 

Francisco Bay area. C, Enlargement of Los Angeles and Orange 

Counties. Geospatial jurisdictional boundaries and tsunamiinundation zone for maps were acquired from Cal-Atlas Geospatial 

Clearinghouse, accessed February 1, 2012, at http://atlas.ca.gov/.
Study Area 5

Monterey

Los 

Angeles Ventura

San 

Diego

Santa 

Barbara

Orange

San Luis

Obispo

1. San Diego

2. Coronado

3. National City

4. Chula Vista

5. Imperial Beach

Oxnard

Carlsbad

Santa Barbara

Malibu

Encinitas

1. Marina

2. Sand City

3. Seaside

4. Monterey

5. Pacific Grove

6. Carmel-by-the-Sea

Pismo Beach

Goleta

36°0' N

35°0' N

34°0' N

33°0' N

NEVADA

CALIFORNIA

1 2

3

4 6

5

Morro Bay

Grover Beach

Carpinteria

Oceanside

Solana Beach Del Mar

1

2

3

4

5

San Buenaventura (Ventura)

Port Hueneme

Humboldt

Mendocino

Sonoma

Napa

Marin

Del Norte

Santa Cruz

Eureka Arcata

Fort Bragg

Point Arena

Ferndale

Trinidad

Crescent 

City

124°0' W 123°0' W 122°0' W 121°0' W 120°0' W 119°0' W 118°0' W 117°0' W

Capitola

42°0' N

41°0' N

39°0' N

38°0' N

37°0' N

40°0' N

0 20 KILOMETERS

0 20 MILES

Santa 

 Clara

Pacific

Ocean

Santa Cruz

Incoporated city with land

in tsunami-inundation zone

County with land

in tsunami-inundation zone

Other California counties

Coastline with mapped

tsunami-inundation zone

Avalon

OREGON

CALIFORNIA

San Francisco

San Mateo

Solano

Alameda

Contra Costa

MEXICO

Los Angeles

Newport Beach

Dana Point

Torrance

Huntington Beach

Costa Mesa

Seal Beach

Westminster

Laguna Beach

Rancho 

Palos Verdes

Santa Monica

El Segundo

Redondo 

Beach

Palos 

Verdes

Estates

Manhattan Beach

Los Angeles

Orange

Hermosa Beach

San Clemente

0 10 KILOMETERS

0 10 MILES

Long Beach

Brisbane

Benicia

Foster City

South SF

Marin

Alameda

Santa Clara

Contra Costa

Fremont

San Jose

Oakland

Hayward

Vallejo

Richmond

Novato

Redwood City

Alameda

Sunnyvale

San Rafael Hercules

Union City

Pinole

Newark

San Mateo

Pacifica

Menlo Park

Martinez

San Leandro

Mountain 

View

Daly City

Burlingame

San Carlos

Half Moon 

Bay

Larkspur

Palo Alto

East Palo Alto

Solano

Berkeley

Albany

Emeryville

San Francisco

Mill 

Valley

Sausalito

San Francisco (SF)

Millbrae

0 10 KILOMETERS

0 10 MILES

San 

Mateo

Belvedere

A

B A

C

B

C
6 Community Exposure to Tsunami Hazards in California

cities or unincorporated places are aggregated and reported 

at the county level as “remaining land” for a given county 

throughout the report. 

The tsunami-inundation zone used in this study is based 

on cumulative modeling efforts that incorporate a variety of 

far-field, local earthquake, and local landslide sources. It was 

created for 35 separate regions covering the most significant 

population and economic centers along the California coast 

and does not represent potential inundation along the entire 

coastline (fig. 2). Local fault sources include the Cascadia 

Subduction Zone (for northern coastal communities) and 

other local faults in the Santa Barbara Channel (AnacapaDume and Channel Islands thrust faults, 1927 Point Arguello 

earthquake), between Santa Monica and San Diego Bay 

(Catalina Fault, Newport Inglewood Fault, Oceanside thrust 

fault, San Clemente Fault, and San Mateo thrust fault), and 

around the San Francisco Bay area (San Gregorio, HaywardRodgers Creek, and Point Reyes Faults). Landslide sources 

include submarine scenario landslides within or near Goleta, 

Palos Verdes, Coronado Canyon, and Monterey Canyon. 

Far-field tsunamigenic earthquake sources include several 

subduction zones—Alaska-Aleutian, Kuril-Japan, Chilean, 

Marianna-Izu-Bonin, and Cascadia (distant source for central 

and southern California communities). Descriptions of each 

tsunami source, such as the length, width, depth, slip and 

magnitudes for earthquake scenarios can be found in Wilson 

and others (2010).

The tsunami-inundation zone was generated at 3 arcsecond (75-to-90 meter) resolution grids for all areas and 

then enhanced with 1 arc-second (25-to-30 meter) resolution 

grids in the major port areas (Los Angeles, Long Beach, San 

Francisco, and San Diego). The final tsunami-inundation 

zone represents the maximum inundation in each of the areas 

from the various tsunami sources and is refined to a higher 

level of accuracy using high-resolution elevation data (3 to 5 

meters) onshore. The delineation of the inundation zone also 

included field verification by geologists and local emergency 

planners for their specific jurisdictions (Barberopoulou and 

others, 2009). In most areas, potential tsunami inundation is 

dominated by one or two scenarios, primarily the Cascadia 

Subduction Zone, local submarine faults or landslides, or a 

magnitude 9.2 earthquake from the eastern Aleutian Islands 

(appendix 1; Wilson and others, 2010).

Because the tsunami-inundation zone identifies the 

maximum areas of inundation from various earthquake and 

landslide sources, it is not meant to imply that all delineated 

areas would be inundated by a single future tsunami. Also, 

the areas in the identified tsunami-inundation zone are not 

equally at risk from inundation; areas closer to the shoreline 

are more likely to be affected than areas on the landward edge 

of the zone because of a presumed greater flooding depth 

and stronger currents. Finally, the tsunami-inundation zone 

does not provide any indicator of the probability of specific 

earthquake or landslide scenarios. The tsunami-inundation 

zone used in this study is a guide for emergency planning 

and is not a prediction for a future event, because the actual 

inundation extent, depth, speed, and impact forces of a 

future tsunami will be determined by specific aspects of the 

source (for example, the location, depth, and magnitude of an 

earthquake), the ocean conditions through which it travels, 

and the topography over which it moves (for example, the 

influence of vegetation and human structures on changing 

flow dynamics). 

Variations in Community Exposure

We use the amount and percentage of 7 populationrelated variables—developed land, residents, employees, 

public venues, dependent-population facilities, communitysupport businesses, and beach and park attendance—to 

describe the variation in community exposure to tsunami 

hazards among the 94 communities and 20 counties. We 

chose these variables because they are all indicators of human 

occupation and land use in tsunami-prone areas. They are 

also data that U.S. jurisdictions are encouraged to collect as 

they develop hazard-mitigation plans (Federal Emergency 

Management Agency, 2001) to qualify for funds under the 

U.S. Hazard Mitigation Grant Program in accordance with the 

Disaster Mitigation Act of 2000, Public Law 106-390. 

Calculating the number and distribution of individuals 

and businesses in tsunami-prone areas shows emergency 

managers and community planners where risk and warning 

education may be most needed. Calculating the percentage 

of community assets in tsunami-prone areas provides insight 

about the relative impact of losses to an entire community. 

For example, two coastal communities (one small and one 

large) both may have 100 homes and businesses in a tsunamiinundation zone; however, this may only represent 5 percent 

of total assets in the larger community and 100 percent in the 

smaller community. As such, the smaller community may have 

greater difficulty responding to and recovering from the same 

event, given that every structure in their community could be 

damaged or destroyed. The relative exposure of a community’s 

urban footprint to a predicted threat may influence their 

overall sensitivity and adaptive capacity to the threat. 

Analyses were completed using geographic-informationsystem (GIS) software to overlay geospatial data representing 

population counts, land-cover classification, administrative 

boundaries, and tsunami-inundation zones. Before analysis, we 

transformed all geospatial data to share the same projection and 

datum, specifically the 1983 North American Datum (NAD83) 

enhanced by the High Accuracy Reference Network (HARN) for 

State Plane California Zone I, which uses Lambert Conformal 

Conic as its base projection. Spatial analysis of vector data (for 

example, business points and census-block polygons) focused 

on determining if points or polygons are inside the tsunamiinundation-zone polygons. If GIS-based population polygons 

overlapped hazard polygons, final population values were adjusted 

proportionately using the spatial ratio of each sliver within or 

outside of the tsunami-inundation zone. 
Variations in Community Exposure 7

Land Cover

Describing the patterns of land cover, particularly patterns 

of human development, in predicted hazard zones is an important 

component of an exposure assessment. We used a subset of 

the 2006 National Land Cover Database (NLCD) (Homer and 

others, 2004 and 2012; Multi-Resolution Land Characteristics 

Consortium, 2011) to identify land-cover types in the study area. 

NLCD products are coded by automated techniques from 30-meter 

spatial resolution Landsat Thematic Mapper digital satellite 

imagery and verified with field visits. The base scale of 1:100,000 

for mapping applications and project accuracy standards of 85 

percent make NLCD data (represented as 30-meter grid cells or 

pixels) appropriate for regional landscape-pattern identification. 

Figure 3 portrays several communities (Crescent City, Eureka, 

Belvedere, Alameda, and Long Beach) in terms of their land 

cover and demonstrates how most tsunami-prone land in these 

communities is classified as developed.

In addition to identifying all types of land cover in the 

tsunami-inundation zone, we calculated the amount and 

percentage of developed land within this zone for each community. 

We assumed that population and asset exposure increases as the 

amount and percentage of developed land within tsunami-prone 

areas increases (Wood, 2009). To assess variations in community 

exposure to tsunami hazards, we focus on three NLCD classes of 

developed land: 

•	 High-intensity developed pixels, which contain more than 80 

percent impervious surfaces, contain little or no vegetation, 

and typically represent heavily built-up urban centers, large 

buildings, and abundant paved surfaces, such as runways and 

interstate highways;

•	 Medium-intensity developed pixels, which contain 50 to 79 

percent impervious surfaces, are a mix of constructed and vegetated surfaces, and typically represent single-family housing 

units and associated outbuildings; and

•	 Low-intensity developed pixels, which contain 21 to 49 percent 

impervious surfaces and are similar to medium-intensity 

developed pixels with the addition of roads and associated trees 

(Multi-Resolution Land Characteristics Consortium, 2011).

We chose not to include a fourth category of developed land 

(“developed, open space”) because it identifies areas that have 

low impervious surfaces and are primarily covered in vegetation, 

such as lawn grass on large lots, golf courses, cemeteries, beaches, 

and parks. Although these areas will often contain people, we felt 

the number of people in these areas was similar to natural areas 

used for recreational purposes (for example, beaches and forests); 

therefore, including open-space developed while excluding 

undeveloped areas was considered to be inappropriate. In addition, 

many of the areas classified as open-space developed are taken 

into account through other variables, such as public venues, beach 

attendance, and State parks.

For those not familiar with data derived from satellite 

imagery, it is important to note that the developed classes denote 

the amount of impervious surfaces within a grid cell and not the 

density of development (that is, “high-intensity” developed is 

not the same as “high-density” developed). For example, a cell 

completely covered by a parking lot and another grid cell containing 

a 10-story apartment complex would both be characterized as 

high-intensity developed land cover, because of the high amounts of 

impervious surfaces in each cell (that is, the rooftops), but only the 

apartment complex would be considered high-density development. 

Ancillary data, such as elevation, tax-assessor parcels, or additional 

imagery bands, could help one distinguish between the two landuse types and to determine the density of development within a 

specific cell. It is for this reason that NLCD data are used to discuss 

land-cover trends across communities and regions, instead of sitespecific, land-use conditions. 

The distribution of land-cover types (by area) in tsunamiprone areas was determined for the entire study area based on a 

spatial overlay of 2006 NLCD data, administrative boundaries, 

and the tsunami-inundation zone (fig. 4). Percentages represent the 

amount of land area classified as a specific land-cover class (for 

example, grassland) relative to the total hazard-prone area. For 

the purposes of this report, all wetland-related NLCD classes are 

aggregated into one class, as are all forest-related classes. Thirtynine percent of the land-cover distribution in the California tsunamiinundation zone is classified as developed, including low-intensity 

(12 percent), medium-intensity (18 percent), and high-intensity (9 

percent) classes. The remaining tsunami-prone land is classified as 

pasture/hay, grassland, and shrub/scrub (22 percent), wetlands (20 

percent), open-space developed (8 percent), barren land (6 percent), 

cultivated crops (4 percent), and forest (1 percent). 

Although approximately 60 percent of tsunami-prone areas 

are not classified as developed, these undeveloped areas (for 

example, forest, shrub/scrub, open space, grassland, and wetlands) 

can still represent tsunami vulnerability issues in the 20 counties. 

For example, undeveloped areas can attract significant numbers 

of recreationists (for example, beach visitors, forest hikers, or 

waterway paddlers). In addition, undeveloped areas may represent 

significant habitats, natural resources, or ecosystem services (for 

example, water-quality improvement or juvenile-fish habitats), 

either locally or regionally. 

Assessing land-cover distributions at the county level 

indicates that there is substantial diversity in how counties are using 

tsunami-prone areas (fig. 5). Of the areas on the California coast 

with mapped tsunami-inundation zones, Humboldt County has the 

greatest amount of land in the tsunami-inundation zone, but the bulk 

of it is classified as pasture and cultivated crops, wetlands, scrub/

shrub and grassland, and barren land (which typically signify the 

presence of beaches when characterizing coastal zones). The bulk 

of developed land in areas mapped as tsunami prone is in Alameda, 

Los Angeles, Orange, and San Diego Counties. Across the study 

area, the majority of developed land in the tsunami-inundation 

zone is classified as medium- and low-intensity developed, which 

likely represents residential housing and associated buildings (for 

example, garages and sheds). The high amounts of high-intensity 

developed land in Alameda and Los Angeles Counties likely 

represent highways, commercial waterfronts, ports and harbors, and 

dense single-family housing characteristic of larger coastal cities. 

The amount (fig. 6A) and percentage (fig. 6B) of developed 

land (that is, NLCD cells classified as low-, medium-, or 
8 Community Exposure to Tsunami Hazards in California

Shrub/scrub

Grassland

Barren land

Forest

Landward extent of 

tsunami-inundation zone

Land-cover class

Open water

Developed, open space

Developed, low intensity

Developed, medium intensity

Developed, high intensity

Pasture or cultivated crops

Crescent City

41°48'

41°46'

41°44'

Sausalito

Belvedere

37°54'

37°52'

Alameda

Oakland

Emeryville

122°30' 122°28' 122°20' 122°18' 122°16' 122°14'

37°48'

37°46'

37°44'

Eureka

Arcata

124°14' 124°12' 124°14' 124°12' 124°10' 124° 8' 124° 6' 124°4'

40°52'

40°50'

40°48'

40°46'

Long Beach

Seal Beach

118°14' 118°12' 118°10' 118°8' 118° 6' 118° 4'

33°52'

33°50'

33°48'

33°46'

33°44'

0 1 KILOMETER

0 1 MILE

0 1 KILOMETER

0 1 MILE

0 1 KILOMETER

0 1 MILE

0 1 KILOMETER

0 1 MILE

0 1 KILOMETER

0 1 MILE

Pacific Ocean

PACIFIC

OCEAN

San Francisco Bay

Richardson

Bay

San Francisco

Bay

Wetland PACIFIC OCEAN

A B

C D

E

Figure 3. Maps of the tsunamiinundation zone and land-cover 

data from the 2006 National 

Land Cover Database (MultiResolution Land Characteristics 

Consortium, 2011) for the 

communities of (A) Crescent 

City, (B) Eureka, (C) Belvedere, 

(D) Alameda, and (E) Long 

Beach, California. Geospatial 

jurisdictional boundaries for 

maps were acquired from CalAtlas Geospatial Clearinghouse, 

accessed February 1, 2012, at 

http://atlas.ca.gov/.
Variations in Community Exposure 9

Del Norte

County name

Humboldt

Mendocino

Sonoma

Marin

Napa

Solano

Contra Costa

Alameda

Santa Clara

San Mateo

San Francisco

Santa Cruz

Monterey

San Luis Obispo

Santa Barbara

Ventura

Los Angeles

Orange

San Diego

Developed, open space 

Barren land 

Forest

Shrub/scrub or grassland

Pasture or cultivated crops 

Wetland

Developed, low intensity

Developed, medium intensity

Developed, high intensity

Amount of land, by type, in tsunami-inundation zone,

in square kilometers

0 40 80 120 160

Developed,

open space

(8%)

Developed, 

low intensity

(12%) 

Developed,

medium

intensity

(18%) 

Developed,

high

intensity

(9%)

Barren 

land

Pasture (6%)

or cultivated 

crops (4%)

Forest (1%)

Shrub/scrub or

grassland (22%)

Wetland (20%)

Figure 4. Pie chart showing distribution of 

National Land Cover Database classes (by 

area) in the California tsunami-inundation 

zone. %, percent.

high-intensity developed) in tsunami-prone areas varies within 

the 94 communities and 20 counties. In the y axes of figure 6, 

as well as in subsequent bar graphs in this report, communities 

and counties are arranged by geographic order from north to 

south. The dashed line represents the third-quartile values (75th 

percentile) to highlight communities with the highest relative 

exposure. Third-quartile values are highlighted instead of standard 

deviations because of the wide range and bimodal distribution of 

values—a common occurrence for many results summarized in 

the report. Communities with values higher than the third-quartile 

value are in the top 25 percent of the communities in a certain 

category and therefore have the highest relative exposure.

The cities of Oakland and Los Angeles contain the largest 

areas of developed land in the tsunami-inundation zone (25 and 

22 square kilometers, respectively), but these lands represent 

relatively low percentages of the total developed land in each 

jurisdiction (24 and 3 percent, respectively). There are several 

communities, however, that have relatively low amounts of 

developed land in the tsunami-inundation zone, which represent 

a high percentage of total land within the jurisdiction (for 

example, Crescent City, Belvedere, Emeryville, and Del Mar). 

The amount of potential flooding and subsequent destruction 

in these smaller communities may be considerably less than in 

cities such as Oakland and Los Angeles; however, their ability to 

effectively respond to and recover from a tsunami may be also 

be considerably less than the larger cities because such a high 

percentage of the community could be affected. Examining both 

attributes collectively, there are several communities (for example, 

Alameda, Morro Bay, Coronado, Eureka, and communities in 

unincorporated areas of Humboldt County) that are above the 

third-quartile values for both amount and percentage of developed 

land in the tsunami-inundation zone, meaning these communities 

could experience a high amount of damage that also represents a 

high percentage of their total assets. 

Residents

The number and type of residents in the tsunamiinundation zone were assessed by overlaying geospatial 

data representing the tsunami-inundation zone, community 

boundaries, and block-level population counts compiled 

for the 2010 U.S. Census (U.S. Census Bureau, 2012). The 

tsunami-inundation zone contains approximately 267,347 

residents and 117,380 occupied households (table 1), both 

representing approximately 1 percent of the 20 counties. 

The number (fig. 7A) and percentage (fig. 7B) of residents 

in the tsunami-inundation zone vary greatly across the 

Figure 5. Plot showing the amount of land by 

National Land Cover Database class in the tsunamiinundation zone of California coastal counties.
10 Community Exposure to Tsunami Hazards in California

Figure 6. Plots showing amount (A) and percentage (B) of developed land in the California tsunami-inundation zone. km2, square kilometers.

A Amount of developed land (km B Percentage of developed land in tsunami-inundation zone 2) in tsunami-inundation zone

3rd Quartile (13%)

Sonoma Co.

Napa County

San Francisco Co.

San Mateo

County

Contra 

Costa

County

Humbolt

County

Santa Clara

County

Mendocino

County

Del Norte

County

Marin

County

Alameda

County

Solano

County

Sonoma Co.

Napa County

San Francisco Co.

San Mateo

County

Contra Costa

County

Humbolt

County

Santa Clara

County

Mendocino

County

Del Norte

County

Marin

County

Alameda

County

Solano

County

0 10 20 30 0% 40% 80%

Low Intensity

Medium Intensity

High Intensity

Crescent City

Remaining land

Trinidad

Arcata

Eureka

Ferndale

Remaining land

Fort Bragg

Point Arena

Remaining land

Remaining land

Novato

San Rafael

Larkspur

Mill Valley

Belvedere

Sausalito

Remaining land

Remaining land

Vallejo

Benicia

Remaining land

Martinez

Hercules

Pinole

Richmond

Remaining land

Albany

Berkeley

Emeryville

Oakland

Alameda

San Leandro

Hayward

Union City

Fremont

Newark

Remaining land

San Jose

Sunnyvale

Mountain View

Palo Alto

Remaining land

San Francisco

East Palo Alto

Menlo Park

Redwood City

San Carlos

Foster City

San Mateo

Burlingame

Millbrae

South San Francisco

Brisbane

Daly City

Pacifica

Half Moon Bay

Remaining land

Crescent City

Remaining land

Trinidad

Arcata

Eureka

Ferndale

Remaining land

Fort Bragg

Point Arena

Remaining land

Remaining land

Novato

San Rafael

Larkspur

Mill Valley

Belvedere

Sausalito

Remaining land

Remaining land

Vallejo

Benicia

Remaining land

Martinez

Hercules

Pinole

Richmond

Remaining land

Albany

Berkeley

Emeryville

Oakland

Alameda

San Leandro

Hayward

Union City

Fremont

Newark

Remaining land

San Jose

Sunnyvale

Mountain View

Palo Alto

Remaining land

San Francisco

East Palo Alto

Menlo Park

Redwood City

San Carlos

Foster City

San Mateo

Burlingame

Millbrae

South San Francisco

Brisbane

Daly City

Pacifica

Half Moon Bay

Remaining land

3rd Quartile (2 km ) 2

EXPLANATION
Variations in Community Exposure 11

Figure 6.—Continued

0 10 20 30 0% 40% 80%

San Diego

County

Ventura

County

Orange

County

Monterey

County

Santa Cruz

County

Santa Barbara

County

Los Angeles

County

San Luis Obispo

County

Santa Cruz

Capitola

Remaining land

Marina

Seaside

Sand City

Monterey

Pacific Grove

Carmel-by-the-Sea

Remaining land

Morro Bay

Pismo Beach

Grover Beach

Remaining land

Goleta

Santa Barbara

Carpinteria

Remaining land

San Buenaventura (Ventura)

Oxnard

Port Hueneme

Remaining land

Malibu

Los Angeles

Santa Monica

El Segundo

Manhattan Beach

Hermosa Beach

Redondo Beach

Torrance

Palos Verdes Estates

Rancho Palos Verdes

Long Beach

Avalon

Remaining land

Seal Beach

Westminster

Huntington Beach

Costa Mesa

Newport Beach

Laguna Beach

Dana Point

San Clemente

Remaining land

Oceanside

Carlsbad

Encinitas

Solana Beach

Del Mar

San Diego

Coronado

National City

Chula Vista

Imperial Beach

Remaining land

San Diego

County

Ventura

County

Orange

County

Monterey

County

Santa Cruz

County

Santa Barbara

County

Los Angeles

County

San Luis Obispo

County

Santa Cruz

Capitola

Remaining land

Marina

Seaside

Sand City

Monterey

Pacific Grove

Carmel-by-the-Sea

Remaining land

Morro Bay

Pismo Beach

Grover Beach

Remaining land

Goleta

Santa Barbara

Carpinteria

Remaining land

San Buenaventura (Ventura)

Oxnard

Port Hueneme

Remaining land

Malibu

Los Angeles

Santa Monica

El Segundo

Manhattan Beach

Hermosa Beach

Redondo Beach

Torrance

Palos Verdes Estates

Rancho Palos Verdes

Long Beach

Avalon

Remaining land

Seal Beach

Westminster

Huntington Beach

Costa Mesa

Newport Beach

Laguna Beach

Dana Point

San Clemente

Remaining land

Oceanside

Carlsbad

Encinitas

Solana Beach

Del Mar

San Diego

Coronado

National City

Chula Vista

Imperial Beach

Remaining land

Low Intensity

Medium Intensity

High Intensity

3rd Quartile (2 km ) 3rd Quartile (13%) 2

A Amount of developed land (km B Percentage of developed land in tsunami-inundation zone 2) in tsunami-inundation zone

EXPLANATION
12 Community Exposure to Tsunami Hazards in California

0 20,000 40,000 0% 20% 40% 60%

3rd Quartile (5%)

Sonoma Co.

Napa County

San Francisco Co.

San Mateo

County

Contra 

Costa

County

Humbolt

County

Santa Clara

County

Mendocino

County

Del Norte

County

Marin

County

Alameda

County

Solano

County

Sonoma Co.

Napa County

San Francisco Co.

San Mateo

County

Contra Costa

County

Humbolt

County

Santa Clara

County

Mendocino

County

Del Norte

County

Marin

County

Alameda

County

Solano

County

Crescent City

Remaining land

Trinidad

Arcata

Eureka

Ferndale

Remaining land

Fort Bragg

Point Arena

Remaining land

Remaining land

Novato

San Rafael

Larkspur

Mill Valley

Belvedere

Sausalito

Remaining land

Remaining land

Vallejo

Benicia

Remaining land

Martinez

Hercules

Pinole

Richmond

Remaining land

Albany

Berkeley

Emeryville

Oakland

Alameda

San Leandro

Hayward

Union City

Fremont

Newark

Remaining land

San Jose

Sunnyvale

Mountain View

Palo Alto

Remaining land

San Francisco

East Palo Alto

Menlo Park

Redwood City

San Carlos

Foster City

San Mateo

Burlingame

Millbrae

South San Francisco

Brisbane

Daly City

Pacifica

Half Moon Bay

Remaining land

Crescent City

Remaining land

Trinidad

Arcata

Eureka

Ferndale

Remaining land

Fort Bragg

Point Arena

Remaining land

Remaining land

Novato

San Rafael

Larkspur

Mill Valley

Belvedere

Sausalito

Remaining land

Remaining land

Vallejo

Benicia

Remaining land

Martinez

Hercules

Pinole

Richmond

Remaining land

Albany

Berkeley

Emeryville

Oakland

Alameda

San Leandro

Hayward

Union City

Fremont

Newark

Remaining land

San Jose

Sunnyvale

Mountain View

Palo Alto

Remaining land

San Francisco

East Palo Alto

Menlo Park

Redwood City

San Carlos

Foster City

San Mateo

Burlingame

Millbrae

South San Francisco

Brisbane

Daly City

Pacifica

Half Moon Bay

Remaining land

3rd Quartile (1,347)

A Number of residents in tsunami-inundation zone B Percentage of residents in tsunami-inundation zone

Figure 7. Plots showing number (A) and percentage (B) of residents in the California tsunami-inundation zone. %, percent.
Variations in Community Exposure 13

San Diego

County

Ventura

County

Orange

County

Monterey

County

Santa Cruz

County

Santa Barbara

County

Los Angeles

County

San Luis Obispo

County

Santa Cruz

Capitola

Remaining land

Marina

Seaside

Sand City

Monterey

Pacific Grove

Carmel-by-the-Sea

Remaining land

Morro Bay

Pismo Beach

Grover Beach

Remaining land

Goleta

Santa Barbara

Carpinteria

Remaining land

San Buenaventura (Ventura)

Oxnard

Port Hueneme

Remaining land

Malibu

Los Angeles

Santa Monica

El Segundo

Manhattan Beach

Hermosa Beach

Redondo Beach

Torrance

Palos Verdes Estates

Rancho Palos Verdes

Long Beach

Avalon

Remaining land

Seal Beach

Westminster

Huntington Beach

Costa Mesa

Newport Beach

Laguna Beach

Dana Point

San Clemente

Remaining land

Oceanside

Carlsbad

Encinitas

Solana Beach

Del Mar

San Diego

Coronado

National City

Chula Vista

Imperial Beach

Remaining land

San Diego

County

Ventura

County

Orange

County

Monterey

County

Santa Cruz

County

Santa Barbara

County

Los Angeles

County

San Luis Obispo

County

Santa Cruz

Capitola

Remaining land

Marina

Seaside

Sand City

Monterey

Pacific Grove

Carmel-by-the-Sea

Remaining land

Morro Bay

Pismo Beach

Grover Beach

Remaining land

Goleta

Santa Barbara

Carpinteria

Remaining land

San Buenaventura (Ventura)

Oxnard

Port Hueneme

Remaining land

Malibu

Los Angeles

Santa Monica

El Segundo

Manhattan Beach

Hermosa Beach

Redondo Beach

Torrance

Palos Verdes Estates

Rancho Palos Verdes

Long Beach

Avalon

Remaining land

Seal Beach

Westminster

Huntington Beach

Costa Mesa

Newport Beach

Laguna Beach

Dana Point

San Clemente

Remaining land

Oceanside

Carlsbad

Encinitas

Solana Beach

Del Mar

San Diego

Coronado

National City

Chula Vista

Imperial Beach

Remaining land

0 20,000 40,000 0% 20% 40% 60%

A Number of residents in tsunami-inundation zone B Percentage of residents in tsunami-inundation zone

3rd Quartile (1,347) 3rd Quartile (5%)

Figure 7.—Continued
14 Community Exposure to Tsunami Hazards in California

20 counties. The City of Alameda has the highest number of 

residents in the tsunami-inundation zone (39,515 residents), and 

several communities (for example, Emeryville and Belvedere) 

have more than 30 percent of their residents in the tsunamiinundation zone. Several areas have high numbers but relatively 

low percentages of total residents in the tsunami-inundation 

zone (for example, the cities of Long Beach, Los Angeles, and 

San Francisco), whereas other areas have low numbers and high 

percentages of residents in tsunami-prone areas (for example, the 

cities Belvedere, Emeryville, and Coronado). Several cities, (for 

example, Alameda, Seal Beach, Huntington Beach, and Newport 

Beach) have both relatively high numbers and high percentages of 

their residents in the tsunami-inundation zone (denoted by these 

cities having values above the third quartile in both categories). 

Twelve percent of the residents in tsunami-prone areas live in 

unincorporated communities outside of the incorporated cities (fig. 

1A, for example), indicating a need for awareness programs and 

evacuation planning in less developed areas. 

Demographic factors, such as age, ethnicity and tenancy, 

can amplify an individual’s sensitivity to hazards (Morrow, 1999; 

Ngo, 2003; Cutter and others, 2003; Laska and Morrow, 2007). 

Therefore, in addition to general population counts, we calculated 

the number of residents in tsunami-prone areas according to 

ethnicity (Hispanic or Latino), race (American Indian and Alaska 

Native, Asian, Black or African American, Native Hawaiian and 

other Pacific Islander, and White —either all alone for each race 

or in combination with one or more other races), age (individuals 

less than 5 and more than 65 years in age), gender with particular 

family structures (female-headed households with children under 

Table 1. Block-level demographic characteristics for residential populations in the California tsunami-inundation zone, based on the 

2010 U.S. Census.

[n.a., not applicable]

Demographic category Tsunami-inundation 

zone

Tsunami-inundation 

zone percentage2

Study-area

percentage2

Community maximum 

percentage

Total population 267,347 n.a. 1 n.a.

Hispanic or Latino 35,620 13 <1 68

Race—White1 205,644 77 1 100

Race—Black or African American1 15,901 6 1 35

Race—American Indian and Alaska Native1 5,178 2 1 19

Race—Asian1 37,373 14 1 85

Race—Native Hawaiian and Other Pacific Islander1 1,958 1 1 10

Race—Some other race 15,063 6 <1 37

Population less than 5 years old 11,166 4 1 19

Population more than 65 years old 41,596 16 1 59

Population in institutionalized group quarters 3,595 1 2 26

Population in noninstitutionalized group quarters 15,334 6 4 100

Total occupied households 117,380 n.a. 1 n.a.

Renter-occupied households 59,863 51 1 100

Single-mother-occupied households 4,817 4 1 16

1

Alone or in combination with one or more other races.

2

Tsunami-hazard-zone percentages refer to the percentage of individuals (or households for the last three rows) in the tsunami-inundation zone of a specific 

demographic category. Study area percentages refer to the percentage of individuals (or households) in the 20 coastal counties of a specific demographic category.

18 years of age and no spouse present), and tenancy (renteroccupied households). 

Categories to discuss demographic sensitivities are not 

based on extensive studies of residents in the California tsunamiinundation zone, but instead on past social-science research of 

all types of disasters (for example, earthquakes, tornadoes, and 

hurricanes). It is not implied that all individuals of a certain group 

will exhibit identical behavior. The extent of these demographic 

sensitivities will be influenced by variations in local physical and 

social context, level of preparedness before a tsunami, and ability 

to respond during an event.

Race and ethnicity have been shown to influence individual 

sensitivity to natural hazards because of historic patterns of social 

inequalities within the United States that can result in minority 

communities lacking resources to prepare and mitigate (Cutter 

and others, 2003; Laska and Morrow, 2007) and potentially being 

excluded from disaster planning efforts (Morrow, 1999). One 

demographic group that may warrant targeted tsunami education 

is individuals that identify themselves as Hispanic or Latino, 

owing to potential language issues with English-only outreach 

or to cultural differences in preparedness. This problem was 

exhibited during the March 11, 2011 tsunami when Spanishspeaking residents over-evacuated many miles inland in several 

central coastal counties in California (Wilson and others, in press). 

Thirteen percent of residents in the tsunami-inundation zone for 

the entire California coastline consider themselves Hispanic or 

Latino, compared to 38 percent for all California residents. This 

percentage ranges from 0 percent to 68 percent (City of San 

Rafael) if one looks at individual communities (fig. 8). In several 
Variations in Community Exposure 15

Percentage of residents in tsunami-inundation zone

that are Hispanic or Latino

0% 40% 80%

Percentage of residents in tsunami-inundation zone

that are Hispanic or Latino

0% 40% 80%

Sonoma Co.

Napa County

San Francisco Co.

San Mateo

County

Contra 

Costa

County

Humbolt

County

Santa Clara

County

Mendocino

County

Del Norte

County

Marin

County

Alameda

County

Solano

County

Crescent City

Remaining land

Trinidad

Arcata

Eureka

Ferndale

Remaining land

Fort Bragg

Point Arena

Remaining land

Remaining land

Novato

San Rafael

Larkspur

Mill Valley

Belvedere

Sausalito

Remaining land

Remaining land

Vallejo

Benicia

Remaining land

Martinez

Hercules

Pinole

Richmond

Remaining land

Albany

Berkeley

Emeryville

Oakland

Alameda

San Leandro

Hayward

Union City

Fremont

Newark

Remaining land

San Jose

Sunnyvale

Mountain View

Palo Alto

Remaining land

San Francisco

East Palo Alto

Menlo Park

Redwood City

San Carlos

Foster City

San Mateo

Burlingame

Millbrae

South San Francisco

Brisbane

Daly City

Pacifica

Half Moon Bay

Remaining land

3rd Quartile (17%)

San Diego

County

Ventura

County

Orange

County

Monterey

County

Santa Cruz

County

Santa Barbara

County

Los Angeles

County

San Luis Obispo

County

Santa Cruz

Capitola

Remaining land

Marina

Seaside

Sand City

Monterey

Pacific Grove

Carmel-by-the-Sea

Remaining land

Morro Bay

Pismo Beach

Grover Beach

Remaining land

Goleta

Santa Barbara

Carpinteria

Remaining land

San Buenaventura (Ventura)

Oxnard

Port Hueneme

Remaining land

Malibu

Los Angeles

Santa Monica

El Segundo

Manhattan Beach

Hermosa Beach

Redondo Beach

Torrance

Palos Verdes Estates

Rancho Palos Verdes

Long Beach

Avalon

Remaining land

Seal Beach

Westminster

Huntington Beach

Costa Mesa

Newport Beach

Laguna Beach

Dana Point

San Clemente

Remaining land

Oceanside

Carlsbad

Encinitas

Solana Beach

Del Mar

San Diego

Coronado

National City

Chula Vista

Imperial Beach

Remaining land

3rd Quartile (17%)

Figure 8. Plot showing percentage of residents in the California tsunami-inundation zone that identify themselves as Hispanic or Latino. %, percent.
16 Community Exposure to Tsunami Hazards in California

communities, the majority of individuals in the tsunami-inundation 

zone identify themselves as Hispanic or Latino, including San 

Rafael, East Palo Alto, Seaside, Avalon, and communities in the 

unincorporated parts of Monterey and San Mateo Counties. 

Relative to race percentages for the entire State, the 

percentage of residents in the tsunami-inundation zone is 

higher for White (77 percent compared to 62 percent for 

the State), and relatively equal for other races, including 

Black or African American (6 percent compared to 7 percent 

for the State), Asian (14 percent compared to 15 percent 

for the State), American Indian and Alaska Native (both 

approximately 2 percent), and Native Hawaiian and Other 

Pacific Islander (both less than 1 percent). Within the 94 

communities and 20 counties, the maximum percentage of 

residents in the tsunami-inundation zone reporting a nonWhite race (alone or in combination with one or more other 

races) is low for most race categories, including Black or 

African American (35 percent), American Indian and Alaska 

Native (19 percent), and Native Hawaiian and Other Pacific 

Islander (10 percent). The one exception is the high percentage 

of residents that identify themselves as Asian (85 percent) 

(table 1). Although the regional third quartile value is only 

10 percent, substantially higher percentages of individuals in 

the tsunami-inundation zone that identify themselves as Asian 

are found in Contra Costa, Alameda, and San Mateo Counties 

(fig. 9). The highest percentages are in the east side of San 

Francisco Bay, such as the cities of Alameda, San Leandro, 

Hayward, and Union City. As was the case regarding high 

concentrations of Hispanic or Latino populations, targeted 

outreach that acknowledges high concentrations of Asian 

populations may be warranted, such as educational materials 

available in multiple languages.

The very young and very old are considered to be 

more vulnerable than other age groups to sudden-onset 

hazards because of potential mobility and health issues 

(Morrow, 1999; Balaban, 2006; McGuire and others, 2007; 

Ngo, 2003). The very young (defined here as individuals 

less than 5 years in age) are considered to have heightened 

vulnerability because they often require direction and 

assistance to evacuate due to their immaturity and size. 

They are also prone to developing post-traumatic stress 

disorders, depressions, anxieties, and behavioral disorders 

as a result of their inability to comprehend and process the 

effects of a disaster (Balaban, 2006). Individuals less than 

5 years in age represent 4 percent of all residents in the 

tsunami-inundation zone, with a range from 0 percent to 19 

percent (in the unincorporated areas of San Diego County) 

at the community level (fig. 10). The high percentage 

in unincorporated San Diego County is because of the 

relatively low numbers of total residents in the tsunamiinundation zone (185 residents). This is also the case for 

the relatively high percentages of the very young in the 

tsunami-inundation zones for the cities of Marina (1 child 

out of 6 at-risk residents) and Seaside (2 children out of 21 

at-risk individuals). Because of the small numbers of at-risk 

individuals in both locations, the resulting high percentages 

are not truly reflective of the underlying issue of children in 

tsunami-inundation zones. Instead, the City of San Rafael 

(10 percent) may better reflect the extent of this issue given 

the larger amount of residents (3,027) in the tsunamiinundation zone.

Individuals older than 65 years are considered also 

to have heightened vulnerability due to potential mobility 

and health issues, reluctance to evacuate, the need for 

special medical equipment at shelters (McGuire and others, 

2007), and the lack of social and economic resources to 

recover (Morrow, 1999; Ngo, 2003). Specific to tsunamis, 

older individuals are considered more sensitive than other 

demographic groups because of possible health and mobility 

issues related to the short evacuation time before tsunami 

inundation from near-field tsunami threats. In addition, 

if a tsunami were to occur in the winter months, openair emergency shelters may not adequately protect older 

individuals from low air temperatures and high precipitation 

(common during winter months on the northern California 

coast), thereby creating additional health complications. 

Individuals older than 65 years represent 16 percent of all 

residents in the tsunami-inundation zone , with a range from 

0 to 59 percent (City of Carmel-by-the-Sea) (fig. 11) at the 

community level. As was the case with the individuals under 

five years in age, the high percentage of at-risk individuals 

that are over 65 years in age in Carmel-by-the-Sea is due to 

a very low number of residents (11) that are in the tsunamiinundation zone. A better reflection of the age-related issues 

is in Mill Valley, where 47 percent of at-risk individuals 

are over 65 years in age from a total at-risk population 

of 1,158 residents. Other communities with relatively 

high percentages (approximately 40 percent of the at-risk 

population) include the cities of Pismo Beach, Novato, 

Dana Point, and Belvedere. Targeted education, evacuation 

training, and relief plans may be needed in communities with 

higher numbers of older populations.

Another group considered more vulnerable to and less 

prepared for extreme events is renters (Morrow, 1999; Burby 

and others, 2003). This may be because (1) higher turnover 

rates for renters may limit their exposure to outreach efforts, 

(2) preparedness campaigns may pay less attention to 

renters, (3) renters typically have lower incomes and fewer 

resources to recover, and (4) renters may not be motivated 

to invest in mitigation measures for rented property (Burby 

and others, 2003). After a disaster, renters also have little 

control over the speed with which rental housing is repaired 

or replaced (Laska and Morrow, 2007). Fifty-one percent of 

the households in the tsunami-inundation zone are renteroccupied (table 1), with a range from 0 percent to 100 

percent (City of Manhattan Beach) (fig. 12). As was the case 

with other demographic attributes, this maximum value is 

inflated due a very low number of at-risk households (three 

in Manhattan Beach). This is also the case in Fort Bragg (18 

of 23 at-risk homes are renter occupied) and unincorporated 

San Diego County (57 of 58 at-risk homes are renter 

occupied). More significant concentrations of renters are 
Variations in Community Exposure 17

0% 30% 60% 90% 0% 30% 60% 90%

Percentage of residents in tsunami-inundation zone

that are Asian

Percentage of residents in tsunami-inundation zone

that are Asian

Sonoma Co.

Napa County

San Francisco Co.

San Mateo

County

Contra 

Costa

County

Humbolt

County

Santa Clara

County

Mendocino

County

Del Norte

County

Marin

County

Alameda

County

Solano

County

Crescent City

Remaining land

Trinidad

Arcata

Eureka

Ferndale

Remaining land

Fort Bragg

Point Arena

Remaining land

Remaining land

Novato

San Rafael

Larkspur

Mill Valley

Belvedere

Sausalito

Remaining land

Remaining land

Vallejo

Benicia

Remaining land

Martinez

Hercules

Pinole

Richmond

Remaining land

Albany

Berkeley

Emeryville

Oakland

Alameda

San Leandro

Hayward

Union City

Fremont

Newark

Remaining land

San Jose

Sunnyvale

Mountain View

Palo Alto

Remaining land

San Francisco

East Palo Alto

Menlo Park

Redwood City

San Carlos

Foster City

San Mateo

Burlingame

Millbrae

South San Francisco

Brisbane

Daly City

Pacifica

Half Moon Bay

Remaining land

3rd Quartile (10%)

San Diego

County

Ventura

County

Orange

County

Monterey

County

Santa Cruz

County

Santa Barbara

County

Los Angeles

County

San Luis Obispo

County

Santa Cruz

Capitola

Remaining land

Marina

Seaside

Sand City

Monterey

Pacific Grove

Carmel-by-the-Sea

Remaining land

Morro Bay

Pismo Beach

Grover Beach

Remaining land

Goleta

Santa Barbara

Carpinteria

Remaining land

San Buenaventura (Ventura)

Oxnard

Port Hueneme

Remaining land

Malibu

Los Angeles

Santa Monica

El Segundo

Manhattan Beach

Hermosa Beach

Redondo Beach

Torrance

Palos Verdes Estates

Rancho Palos Verdes

Long Beach

Avalon

Remaining land

Seal Beach

Westminster

Huntington Beach

Costa Mesa

Newport Beach

Laguna Beach

Dana Point

San Clemente

Remaining land

Oceanside

Carlsbad

Encinitas

Solana Beach

Del Mar

San Diego

Coronado

National City

Chula Vista

Imperial Beach

Remaining land

3rd Quartile (10%)

Figure 9. Plot showing percentage of residents in the California tsunami-inundation zone that identify themselves as Asian (either 

alone or in combination with other races). %, percent.
18 Community Exposure to Tsunami Hazards in California

0% 10% 20% 0% 10% 20%

Percentage of residents in tsunami-inundation

zone that are less than 5 years in age

Percentage of residents in tsunami-inundation

zone that are less than 5 years in age

Sonoma Co.

Napa County

San Francisco Co.

San Mateo

County

Contra 

Costa

County

Humbolt

County

Santa Clara

County

Mendocino

County

Del Norte

County

Marin

County

Alameda

County

Solano

County

Crescent City

Remaining land

Trinidad

Arcata

Eureka

Ferndale

Remaining land

Fort Bragg

Point Arena

Remaining land

Remaining land

Novato

San Rafael

Larkspur

Mill Valley

Belvedere

Sausalito

Remaining land

Remaining land

Vallejo

Benicia

Remaining land

Martinez

Hercules

Pinole

Richmond

Remaining land

Albany

Berkeley

Emeryville

Oakland

Alameda

San Leandro

Hayward

Union City

Fremont

Newark

Remaining land

San Jose

Sunnyvale

Mountain View

Palo Alto

Remaining land

San Francisco

East Palo Alto

Menlo Park

Redwood City

San Carlos

Foster City

San Mateo

Burlingame

Millbrae

South San Francisco

Brisbane

Daly City

Pacifica

Half Moon Bay

Remaining land

3rd Quartile (5%)

San Diego

County

Ventura

County

Orange

County

Monterey

County

Santa Cruz

County

Santa Barbara

County

Los Angeles

County

San Luis Obispo

County

Santa Cruz

Capitola

Remaining land

Marina

Seaside

Sand City

Monterey

Pacific Grove

Carmel-by-the-Sea

Remaining land

Morro Bay

Pismo Beach

Grover Beach

Remaining land

Goleta

Santa Barbara

Carpinteria

Remaining land

San Buenaventura (Ventura)

Oxnard

Port Hueneme

Remaining land

Malibu

Los Angeles

Santa Monica

El Segundo

Manhattan Beach

Hermosa Beach

Redondo Beach

Torrance

Palos Verdes Estates

Rancho Palos Verdes

Long Beach

Avalon

Remaining land

Seal Beach

Westminster

Huntington Beach

Costa Mesa

Newport Beach

Laguna Beach

Dana Point

San Clemente

Remaining land

Oceanside

Carlsbad

Encinitas

Solana Beach

Del Mar

San Diego

Coronado

National City

Chula Vista

Imperial Beach

Remaining land

3rd Quartile (5%)

Figure 10. Plot showing percentage of residents in the California tsunami-inundation zone that are less than 5 years in age. %, percent.
Variations in Community Exposure 19

0% 30% 60% 0% 30% 60%

Percentage of residents in tsunami-inundation

zone that are more than 65 years in age

Percentage of residents in tsunami-inundation

zone that are more than 65 years in age

Sonoma Co.

Napa County

San Francisco Co.

San Mateo

County

Contra 

Costa

County

Humbolt

County

Santa Clara

County

Mendocino

County

Del Norte

County

Marin

County

Alameda

County

Solano

County

Crescent City

Remaining land

Trinidad

Arcata

Eureka

Ferndale

Remaining land

Fort Bragg

Point Arena

Remaining land

Remaining land

Novato

San Rafael

Larkspur

Mill Valley

Belvedere

Sausalito

Remaining land

Remaining land

Vallejo

Benicia

Remaining land

Martinez

Hercules

Pinole

Richmond

Remaining land

Albany

Berkeley

Emeryville

Oakland

Alameda

San Leandro

Hayward

Union City

Fremont

Newark

Remaining land

San Jose

Sunnyvale

Mountain View

Palo Alto

Remaining land

San Francisco

East Palo Alto

Menlo Park

Redwood City

San Carlos

Foster City

San Mateo

Burlingame

Millbrae

South San Francisco

Brisbane

Daly City

Pacifica

Half Moon Bay

Remaining land

3rd 

Quartile (22%)

San Diego

County

Ventura

County

Orange

County

Monterey

County

Santa Cruz

County

Santa Barbara

County

Los Angeles

County

San Luis Obispo

County

Santa Cruz

Capitola

Remaining land

Marina

Seaside

Sand City

Monterey

Pacific Grove

Carmel-by-the-Sea

Remaining land

Morro Bay

Pismo Beach

Grover Beach

Remaining land

Goleta

Santa Barbara

Carpinteria

Remaining land

San Buenaventura (Ventura)

Oxnard

Port Hueneme

Remaining land

Malibu

Los Angeles

Santa Monica

El Segundo

Manhattan Beach

Hermosa Beach

Redondo Beach

Torrance

Palos Verdes Estates

Rancho Palos Verdes

Long Beach

Avalon

Remaining land

Seal Beach

Westminster

Huntington Beach

Costa Mesa

Newport Beach

Laguna Beach

Dana Point

San Clemente

Remaining land

Oceanside

Carlsbad

Encinitas

Solana Beach

Del Mar

San Diego

Coronado

National City

Chula Vista

Imperial Beach

Remaining land

3rd 

Quartile (22%)

Figure 11. Plot showing percentage of residents in the California tsunami-inundation zone that are more than 65 years in age. %, percent.
20 Community Exposure to Tsunami Hazards in California

Percentage of households in tsunami-inundation zone

that are renter occupied

Percentage of households in tsunami-inundation zone

that are renter occupied

Sonoma Co.

Napa County

San Francisco Co.

San Mateo

County

Contra 

Costa

County

Humbolt

County

Santa Clara

County

Mendocino

County

Del Norte

County

Marin

County

Alameda

County

Solano

County

Crescent City

Remaining land

Trinidad

Arcata

Eureka

Ferndale

Remaining land

Fort Bragg

Point Arena

Remaining land

Remaining land

Novato

San Rafael

Larkspur

Mill Valley

Belvedere

Sausalito

Remaining land

Remaining land

Vallejo

Benicia

Remaining land

Martinez

Hercules

Pinole

Richmond

Remaining land

Albany

Berkeley

Emeryville

Oakland

Alameda

San Leandro

Hayward

Union City

Fremont

Newark

Remaining land

San Jose

Sunnyvale

Mountain View

Palo Alto

Remaining land

San Francisco

East Palo Alto

Menlo Park

Redwood City

San Carlos

Foster City

San Mateo

Burlingame

Millbrae

South San Francisco

Brisbane

Daly City

Pacifica

Half Moon Bay

Remaining land

3rd 

Quartile 

(59%)

San Diego

County

Ventura

County

Orange

County

Monterey

County

Santa Cruz

County

Santa Barbara

County

Los Angeles

County

San Luis Obispo

County

Santa Cruz

Capitola

Remaining land

Marina

Seaside

Sand City

Monterey

Pacific Grove

Carmel-by-the-Sea

Remaining land

Morro Bay

Pismo Beach

Grover Beach

Remaining land

Goleta

Santa Barbara

Carpinteria

Remaining land

San Buenaventura (Ventura)

Oxnard

Port Hueneme

Remaining land

Malibu

Los Angeles

Santa Monica

El Segundo

Manhattan Beach

Hermosa Beach

Redondo Beach

Torrance

Palos Verdes Estates

Rancho Palos Verdes

Long Beach

Avalon

Remaining land

Seal Beach

Westminster

Huntington Beach

Costa Mesa

Newport Beach

Laguna Beach

Dana Point

San Clemente

Remaining land

Oceanside

Carlsbad

Encinitas

Solana Beach

Del Mar

San Diego

Coronado

National City

Chula Vista

Imperial Beach

Remaining land

3rd 

Quartile 

(59%)

0% 50% 100% 0% 50% 100%

Figure 12. Plot showing percentage of occupied households in the California tsunami-inundation zone that are renter occupied. %, percent.
Variations in Community Exposure 21

found in the unincorporated portions of Los Angeles County 

(87 percent of 4,149 at-risk homes) and the City of Santa 

Cruz (86 percent of 2,634 at-risk homes). 

Households that are female-headed with children under 

the age of 18, and no spouse present (that is, single-mother 

households) may also be more vulnerable to extreme events. 

Four percent of households in the tsunami-inundation zone 

are single-mother households, which are more likely to have 

limited mobility during an evacuation from a sudden-onset 

hazard and fewer financial resources to draw on to prepare 

for natural hazards and to recover from a disaster (Enarson 

and Morrow, 1998; Laska and Morrow, 2007). The highest 

percentages of households in the tsunami-inundation zone 

that are female-headed, with children under the age of 18, 

and no spouse present are in the City of East Palo Alto 

(16 percent), Berkeley (15 percent), and Crescent City (11 

percent) (fig. 13). 

Another group of residents who will require 

special attention during and before a tsunami are those 

in group quarters, either institutionalized (for example, 

adult correctional, juvenile, and nursing facilities) or 

noninstitutionalized (for example, college/university student 

housing and military quarters) (fig. 14). The unincorporated 

areas of Marin County and the City of Crescent City have 

relatively high percentages of residents in the tsunamiinundation zone that are institutionalized (26 and 8 percent, 

respectively) because of the large correctional facilities in 

those areas (fig. 15). San Quentin State Prison is located in 

unincorporated land of Marin County (fig. 14A), and parts 

of it are in the tsunami-inundation zone (representing 1,591 

of the 6,107 at-risk individuals), as is the Del Norte County 

Jail located in Crescent City. Los Angeles and Mill Valley 

also have relatively high percentages of institutionalized 

residents in group quarters (6 percent each) located in the 

tsunami-prone area. This population is a concern during a 

tsunami because they will require a structured evacuation 

and continued supervision to ensure the safety of both the 

institutionalized populace and the neighboring communities.

As for noninstitutionalized residents in group quarters, 

the cities of Albany and National City have the highest 

percentage (100 and 99 percent, respectively) in the tsunamiinundation zone (fig. 16). The high percentage in Albany 

reflects a very small number (36 people) in the zone residing 

in this type of group quarters, whereas the high percentage 

in National City is due to more than 3,000 people residing 

in military housing at Naval Base San Diego that may be 

in tsunami-prone areas. Significant noninstitutionalized 

populations in other communities likely reflect military 

housing (for example, Eureka and Seaside) or university 

dormitories (for example, Santa Barbara; fig. 14B). Much 

of San Francisco’s noninstitutionalized population, which 

makes up 8 percent (and 834 people) of its total exposed 

population, likely resides in housing for participants in 

government-based education programs (for example, Job 

Corps on Treasure Island, a part of San Francisco completely 

within the tsunami-inundation zone). Noninstitutionalized, 

group-quarters-based populations represent a vulnerable 

population because they are likely to be unfamiliar with local 

hazard issues, may not remember past disasters in the area, 

and may not have been exposed to tsunami-awareness efforts 

if such efforts are geared for homeowners.

Employees

The number and types of employees in tsunami-prone 

areas are based on an overlay of the tsunami-inundation 

zone and the 2011 Infogroup Employer Database (Infogroup, 

2011). Our counts serve as approximations because we were 

unable to field-verify locational data (that is, latitude and 

longitude coordinates) for each of the 1,014,765 businesses 

within the 20 counties of the study area. We used the North 

American Industry Classification System (NAICS) codes 

(U.S. Census Bureau, 2007; see appendix A of Wood, 2007, 

for codes) and the number of employees associated with each 

business to identify the primary business sectors in tsunamiprone areas, an indicator routinely used to evaluate economic 

health and market trends (Bureau of Labor Statistics, 2010).

The tsunami-inundation zone contains approximately 

168,565 employees at 15,335 businesses, both representing 

approximately 2 percent of the businesses and employees 

in the 20 counties. The 15,335 businesses in the tsunamiinundation zone generated approximately $29.8 billion in 

sales in 2010 (2 percent of the study-area total). As with 

residential populations, the number (fig. 17A) and percentage 

(fig. 17B) of employees in tsunami-inundation zones vary 

considerably in the study area. The highest numbers of 

employees working within the tsunami-inundation zone are 

in the cities of Oakland (22,176), Long Beach (16,506), 

Alameda (15,441), and Los Angeles (9,581), reflecting 

the active ports in each city (fig. 1F, for example). The 

related ports of Oakland and Alameda have greater numbers 

of employees in the maximum-tsunami zone than the 

related ports of Los Angeles and Long Beach (37,617 

and 26,087, respectively). Some communities have high 

numbers but low percentages of employees in the tsunamiinundation zone (for example, San Francisco), whereas 

other communities have low numbers of employees that 

represent a high percentage of the city’s workforce in these 

areas (for example, Crescent City, Pacifica, and Belvedere). 

Communities that have both relatively high numbers and 

high percentages of its employees in the tsunami-inundation 

zone include Alameda, Eureka, Sausalito, Emeryville, Santa 

Cruz, Monterey, Seal Beach, and Newport Beach. 

High percentages of employees in the tsunamiinundation zone represent not only public-safety issues 

in the event of an imminent tsunami but also economic 

fragility for a community, as unemployment could increase 

dramatically overnight if a tsunami injures employees or if it 

damages or destroys businesses. Even if a business escapes 

damage or physical disruption from an extreme event, it 

may still experience significant customer and revenue loss 
22 Community Exposure to Tsunami Hazards in California

0% 8% 16% 0% 8% 16%

Percentage of households in tsunami-inundation zone

that are female-headed, with children, no spouse present

Percentage of households in tsunami-inundation zone

that are female-headed, with children, no spouse present

Sonoma Co.

Napa County

San Francisco Co.

San Mateo

County

Contra 

Costa

County

Humbolt

County

Santa Clara

County

Mendocino

County

Del Norte

County

Marin

County

Alameda

County

Solano

County

Crescent City

Remaining land

Trinidad

Arcata

Eureka

Ferndale

Remaining land

Fort Bragg

Point Arena

Remaining land

Remaining land

Novato

San Rafael

Larkspur

Mill Valley

Belvedere

Sausalito

Remaining land

Remaining land

Vallejo

Benicia

Remaining land

Martinez

Hercules

Pinole

Richmond

Remaining land

Albany

Berkeley

Emeryville

Oakland

Alameda

San Leandro

Hayward

Union City

Fremont

Newark

Remaining land

San Jose

Sunnyvale

Mountain View

Palo Alto

Remaining land

San Francisco

East Palo Alto

Menlo Park

Redwood City

San Carlos

Foster City

San Mateo

Burlingame

Millbrae

South San Francisco

Brisbane

Daly City

Pacifica

Half Moon Bay

Remaining land

3rd Quartile (5%)

San Diego

County

Ventura

County

Orange

County

Monterey

County

Santa Cruz

County

Santa Barbara

County

Los Angeles

County

San Luis Obispo

County

Santa Cruz

Capitola

Remaining land

Marina

Seaside

Sand City

Monterey

Pacific Grove

Carmel-by-the-Sea

Remaining land

Morro Bay

Pismo Beach

Grover Beach

Remaining land

Goleta

Santa Barbara

Carpinteria

Remaining land

San Buenaventura (Ventura)

Oxnard

Port Hueneme

Remaining land

Malibu

Los Angeles

Santa Monica

El Segundo

Manhattan Beach

Hermosa Beach

Redondo Beach

Torrance

Palos Verdes Estates

Rancho Palos Verdes

Long Beach

Avalon

Remaining land

Seal Beach

Westminster

Huntington Beach

Costa Mesa

Newport Beach

Laguna Beach

Dana Point

San Clemente

Remaining land

Oceanside

Carlsbad

Encinitas

Solana Beach

Del Mar

San Diego

Coronado

National City

Chula Vista

Imperial Beach

Remaining land

3rd Quartile (5%)

Figure 13. Plot showing percentage of occupied households in the California tsunami-inundation zone that are headed by females with 

children less than 18 years in age and no spouse present. %, percent.
Variations in Community Exposure 23

Figure 14. Photographs of examples of group quarters, including for institutionalized populations at (A) San 

Quentin State Prison (public domain image from California Department of Corrections and Rehabilitation, 2012) and 

noninstitutionalized populations at (B) the University of California at Santa Barbara (image from Adelman and Adelman, 

2010; used with permission).

A

B
24 Community Exposure to Tsunami Hazards in California

Figure 15. Plot showing percentage of residents in the California tsunami-inundation zone that are in institutionalized group quarters. %, percent.

0% 15% 30% 0% 15% 30%

Percentage of residents in the tsunami-inundation zone

that are in institutionalized group quarters 

Sonoma Co.

Napa County

San Francisco Co.

San Mateo

County

Contra 

Costa

County

Humbolt

County

Santa Clara

County

Mendocino

County

Del Norte

County

Marin

County

Alameda

County

Solano

County

Crescent City

Remaining land

Trinidad

Arcata

Eureka

Ferndale

Remaining land

Fort Bragg

Point Arena

Remaining land

Remaining land

Novato

San Rafael

Larkspur

Mill Valley

Belvedere

Sausalito

Remaining land

Remaining land

Vallejo

Benicia

Remaining land

Martinez

Hercules

Pinole

Richmond

Remaining land

Albany

Berkeley

Emeryville

Oakland

Alameda

San Leandro

Hayward

Union City

Fremont

Newark

Remaining land

San Jose

Sunnyvale

Mountain View

Palo Alto

Remaining land

San Francisco

East Palo Alto

Menlo Park

Redwood City

San Carlos

Foster City

San Mateo

Burlingame

Millbrae

South San Francisco

Brisbane

Daly City

Pacifica

Half Moon Bay

Remaining land

3rd Quartile (0%)

San Diego

County

Ventura

County

Orange

County

Monterey

County

Santa Cruz

County

Santa Barbara

County

Los Angeles

County

San Luis Obispo

County

Santa Cruz

Capitola

Remaining land

Marina

Seaside

Sand City

Monterey

Pacific Grove

Carmel-by-the-Sea

Remaining land

Morro Bay

Pismo Beach

Grover Beach

Remaining land

Goleta

Santa Barbara

Carpinteria

Remaining land

San Buenaventura (Ventura)

Oxnard

Port Hueneme

Remaining land

Malibu

Los Angeles

Santa Monica

El Segundo

Manhattan Beach

Hermosa Beach

Redondo Beach

Torrance

Palos Verdes Estates

Rancho Palos Verdes

Long Beach

Avalon

Remaining land

Seal Beach

Westminster

Huntington Beach

Costa Mesa

Newport Beach

Laguna Beach

Dana Point

San Clemente

Remaining land

Oceanside

Carlsbad

Encinitas

Solana Beach

Del Mar

San Diego

Coronado

National City

Chula Vista

Imperial Beach

Remaining land

3rd Quartile (0%)

Percentage of residents in the tsunami-inundation zone

that are in institutionalized group quarters 
Variations in Community Exposure 25

Figure 16. Plot showing percentage of residents in the California tsunami-inundation zone that are in noninstitutionalized group quarters. %, percent.

0% 50% 100% 0% 50% 100%

Sonoma Co.

Napa County

San Francisco Co.

San Mateo

County

Contra 

Costa

County

Humbolt

County

Santa Clara

County

Mendocino

County

Del Norte

County

Marin

County

Alameda

County

Solano

County

Crescent City

Remaining land

Trinidad

Arcata

Eureka

Ferndale

Remaining land

Fort Bragg

Point Arena

Remaining land

Remaining land

Novato

San Rafael

Larkspur

Mill Valley

Belvedere

Sausalito

Remaining land

Remaining land

Vallejo

Benicia

Remaining land

Martinez

Hercules

Pinole

Richmond

Remaining land

Albany

Berkeley

Emeryville

Oakland

Alameda

San Leandro

Hayward

Union City

Fremont

Newark

Remaining land

San Jose

Sunnyvale

Mountain View

Palo Alto

Remaining land

San Francisco

East Palo Alto

Menlo Park

Redwood City

San Carlos

Foster City

San Mateo

Burlingame

Millbrae

South San Francisco

Brisbane

Daly City

Pacifica

Half Moon Bay

Remaining land

3rd Quartile (1%)

San Diego

County

Ventura

County

Orange

County

Monterey

County

Santa Cruz

County

Santa Barbara

County

Los Angeles

County

San Luis Obispo

County

Santa Cruz

Capitola

Remaining land

Marina

Seaside

Sand City

Monterey

Pacific Grove

Carmel-by-the-Sea

Remaining land

Morro Bay

Pismo Beach

Grover Beach

Remaining land

Goleta

Santa Barbara

Carpinteria

Remaining land

San Buenaventura (Ventura)

Oxnard

Port Hueneme

Remaining land

Malibu

Los Angeles

Santa Monica

El Segundo

Manhattan Beach

Hermosa Beach

Redondo Beach

Torrance

Palos Verdes Estates

Rancho Palos Verdes

Long Beach

Avalon

Remaining land

Seal Beach

Westminster

Huntington Beach

Costa Mesa

Newport Beach

Laguna Beach

Dana Point

San Clemente

Remaining land

Oceanside

Carlsbad

Encinitas

Solana Beach

Del Mar

San Diego

Coronado

National City

Chula Vista

Imperial Beach

Remaining land

3rd Quartile (1%)

Percentage of residents in the tsunami-inundation zone

that are in noninstitutionalized group quarters

Percentage of residents in the tsunami-inundation zone

 that are in noninstitutionalized group quarters 
26 Community Exposure to Tsunami Hazards in California

0 12,500 25,000 0% 20% 40% 60% 80%

A Number of employees in tsunami-inundation zone B Percentage of employees in tsunami-inundation zone

3rd Quartile (7%)

Sonoma Co.

Napa County

San Francisco Co.

San Mateo

County

Contra 

Costa

County

Humbolt

County

Santa Clara

County

Mendocino

County

Del Norte

County

Marin

County

Alameda

County

Solano

County

Sonoma Co.

Napa County

San Francisco Co.

San Mateo

County

Contra Costa

County

Humbolt

County

Santa Clara

County

Mendocino

County

Del Norte

County

Marin

County

Alameda

County

Solano

County

Crescent City

Remaining land

Trinidad

Arcata

Eureka

Ferndale

Remaining land

Fort Bragg

Point Arena

Remaining land

Remaining land

Novato

San Rafael

Larkspur

Mill Valley

Belvedere

Sausalito

Remaining land

Remaining land

Vallejo

Benicia

Remaining land

Martinez

Hercules

Pinole

Richmond

Remaining land

Albany

Berkeley

Emeryville

Oakland

Alameda

San Leandro

Hayward

Union City

Fremont

Newark

Remaining land

San Jose

Sunnyvale

Mountain View

Palo Alto

Remaining land

San Francisco

East Palo Alto

Menlo Park

Redwood City

San Carlos

Foster City

San Mateo

Burlingame

Millbrae

South San Francisco

Brisbane

Daly City

Pacifica

Half Moon Bay

Remaining land

Crescent City

Remaining land

Trinidad

Arcata

Eureka

Ferndale

Remaining land

Fort Bragg

Point Arena

Remaining land

Remaining land

Novato

San Rafael

Larkspur

Mill Valley

Belvedere

Sausalito

Remaining land

Remaining land

Vallejo

Benicia

Remaining land

Martinez

Hercules

Pinole

Richmond

Remaining land

Albany

Berkeley

Emeryville

Oakland

Alameda

San Leandro

Hayward

Union City

Fremont

Newark

Remaining land

San Jose

Sunnyvale

Mountain View

Palo Alto

Remaining land

San Francisco

East Palo Alto

Menlo Park

Redwood City

San Carlos

Foster City

San Mateo

Burlingame

Millbrae

South San Francisco

Brisbane

Daly City

Pacifica

Half Moon Bay

Remaining land

3rd Quartile (1,158)

Figure 17. Plots showing number (A) and percentage (B) of employees in the California tsunami-inundation zone. %, percent.
Variations in Community Exposure 27

0 12,500 25,000 0% 20% 40% 60% 80%

A Number of employees in tsunami-inundation zone B Percentage of employees in tsunami-inundation zone

San Diego

County

Ventura

County

Orange

County

Monterey

County

Santa Cruz

County

Santa Barbara

County

Los Angeles

County

San Luis Obispo

County

Santa Cruz

Capitola

Remaining land

Marina

Seaside

Sand City

Monterey

Pacific Grove

Carmel-by-the-Sea

Remaining land

Morro Bay

Pismo Beach

Grover Beach

Remaining land

Goleta

Santa Barbara

Carpinteria

Remaining land

San Buenaventura (Ventura)

Oxnard

Port Hueneme

Remaining land

Malibu

Los Angeles

Santa Monica

El Segundo

Manhattan Beach

Hermosa Beach

Redondo Beach

Torrance

Palos Verdes Estates

Rancho Palos Verdes

Long Beach

Avalon

Remaining land

Seal Beach

Westminster

Huntington Beach

Costa Mesa

Newport Beach

Laguna Beach

Dana Point

San Clemente

Remaining land

Oceanside

Carlsbad

Encinitas

Solana Beach

Del Mar

San Diego

Coronado

National City

Chula Vista

Imperial Beach

Remaining land

San Diego

County

Ventura

County

Orange

County

Monterey

County

Santa Cruz

County

Santa Barbara

County

Los Angeles

County

San Luis Obispo

County

Santa Cruz

Capitola

Remaining land

Marina

Seaside

Sand City

Monterey

Pacific Grove

Carmel-by-the-Sea

Remaining land

Morro Bay

Pismo Beach

Grover Beach

Remaining land

Goleta

Santa Barbara

Carpinteria

Remaining land

San Buenaventura (Ventura)

Oxnard

Port Hueneme

Remaining land

Malibu

Los Angeles

Santa Monica

El Segundo

Manhattan Beach

Hermosa Beach

Redondo Beach

Torrance

Palos Verdes Estates

Rancho Palos Verdes

Long Beach

Avalon

Remaining land

Seal Beach

Westminster

Huntington Beach

Costa Mesa

Newport Beach

Laguna Beach

Dana Point

San Clemente

Remaining land

Oceanside

Carlsbad

Encinitas

Solana Beach

Del Mar

San Diego

Coronado

National City

Chula Vista

Imperial Beach

Remaining land

3rd Quartile (1,158) 3rd Quartile (7%)

Figure 17.—Continued
28 Community Exposure to Tsunami Hazards in California

if the neighborhood and other businesses around it are damaged, 

leading customers to shop elsewhere. Neighborhood effects have 

been found to be especially important for retailers that rely on foot 

traffic (Chang and Falit-Baiamonte, 2002), a potentially significant 

issue for tourism-related retail and food services within California 

coastal communities. 

Societal vulnerability is also influenced by the types of 

businesses in the tsunami-inundation zone. On the basis of 

employee distributions, the primary business sectors in the 

tsunami-inundation zone are in accommodation and food services; 

retail trade; manufacturing; professional, technical and scientific 

services; and construction (fig. 18). Tourism-related businesses (for 

example, accommodations, food services, and retail trade) attract 

local customers and tourists and therefore could contain significant 

numbers of people with little awareness of tsunami hazards or 

of how to evacuate from that location. Employees also may be 

unaware of tsunami hazards or proper evacuation strategies, 

especially if they do not live in tsunami-prone areas themselves, are 

not well connected to the community, and are reliant on business 

owners for information. Nontourism businesses (for example, 

manufacturing and warehousing) tend to involve high numbers of 

employees, low numbers of tourists, heavy machinery that may 

obstruct evacuations, raw materials that could be scattered across 

an area by a tsunami (for example, timber) and possibly hazardous 

materials that require unique storage and response plans. 

To better understand the distribution of business types in 

the tsunami-inundation zone at the community level, the multiple 

NAICS classes have been generalized into two groups based 

on the potential for visitors (high and low). Developing the two 

groups, as well as determining which group the various business 

0% 10%

Percentage of employees, by sector, in tsunami-inundation zone

30%

Management of companies and enterprises

Agriculture, forestry, fishing, and hunting

Mining

Utilities

Construction

Manufacturing

Wholesale trade

Retail trade

Transportation and warehousing

Information

Finance and insurance

Real estate and rental and leasing

Professional, scientific, and technical services

Administrative and support and waste management

Educational services

Health care and social assistance

Arts, entertainment, and recreation

Accommodation and food services

Other services (except public administrationion)

Public administration

Unnamed

20%

Tsunami-inundation zone

Calif. coastal counties

EXPLANATION

types fall within, was a subjective process. It is meant to only 

help in discussing the types of businesses and population groups 

that frequent them across the study area and provide additional 

insight for the development of targeted tsunami preparedness and 

outreach efforts. Businesses with low visitor potential include 

NAICS classes for administrative support and waste management; 

agriculture, forestry, fishing and hunting; construction; finance and 

insurance; information; management of companies; manufacturing; 

mining; professional, scientific, and technical services; public 

administration; real-estate rental and leasing; transportation and 

warehousing utilities; and wholesale trade and other, nonclassified 

businesses. Businesses with high visitor potential include NAICS 

classes for accommodation and food services; arts, entertainment 

and recreation; educational services; health care and social 

assistance; and retail trade.

Across the entire study area, the distribution of employees 

in these two business groupings is approximately equal at 50 

percent in each group (fig. 19). The vertical dotted line in figure 19 

denotes this 50:50 distribution in employee percentages. Several 

communities have similar percentages as the regional trend (for 

example, Eureka and San Francisco). Other communities, as well 

as the unincorporated county lands, have different distributions of 

relative percentage of employees for the two business groupings. 

The stacked bar graphs in figure 19 reflect only the relative 

percentage of employees among the two business groups and not 

the absolute number of employees in the various groups. The lack 

of a stacked bar graph for a community (for example, Trinidad, 

Benicia, and Hercules) indicates that there are no employees, 

according to our regional economic data, in the tsunami-inundation 

zone of these communities. 

Figure 18. Plot showing percentage 

of employees, by business sector, 

in the California (Calif.) tsunamiinundation zone. %, percent.
Variations in Community Exposure 29

0% 50% 100% 0% 50% 100%

Percentage of employees in tsunami-inundation zone Percentage of employees in tsunami-inundation zone

Sonoma Co.

Napa County

San Francisco Co.

San Mateo

County

Contra 

Costa

County

Humbolt

County

Santa Clara

County

Mendocino

County

Del Norte

County

Marin

County

Alameda

County

Solano

County

Crescent City

Remaining land

Trinidad

Arcata

Eureka

Ferndale

Remaining land

Fort Bragg

Point Arena

Remaining land

Remaining land

Novato

San Rafael

Larkspur

Mill Valley

Belvedere

Sausalito

Remaining land

Remaining land

Vallejo

Benicia

Remaining land

Martinez

Hercules

Pinole

Richmond

Remaining land

Albany

Berkeley

Emeryville

Oakland

Alameda

San Leandro

Hayward

Union City

Fremont

Newark

Remaining land

San Jose

Sunnyvale

Mountain View

Palo Alto

Remaining land

San Francisco

East Palo Alto

Menlo Park

Redwood City

San Carlos

Foster City

San Mateo

Burlingame

Millbrae

South San Francisco

Brisbane

Daly City

Pacifica

Half Moon Bay

Remaining land

San Diego

County

Ventura

County

Orange

County

Monterey

County

Santa Cruz

County

Santa Barbara

County

Los Angeles

County

San Luis Obispo

County

Santa Cruz

Capitola

Remaining land

Marina

Seaside

Sand City

Monterey

Pacific Grove

Carmel-by-the-Sea

Remaining land

Morro Bay

Pismo Beach

Grover Beach

Remaining land

Goleta

Santa Barbara

Carpinteria

Remaining land

San Buenaventura (Ventura)

Oxnard

Port Hueneme

Remaining land

Malibu

Los Angeles

Santa Monica

El Segundo

Manhattan Beach

Hermosa Beach

Redondo Beach

Torrance

Palos Verdes Estates

Rancho Palos Verdes

Long Beach

Avalon

Remaining land

Seal Beach

Westminster

Huntington Beach

Costa Mesa

Newport Beach

Laguna Beach

Dana Point

San Clemente

Remaining land

Oceanside

Carlsbad

Encinitas

Solana Beach

Del Mar

San Diego

Coronado

National City

Chula Vista

Imperial Beach

Remaining land

regional 

percentages

Business, 

visitor potential

Low

High

EXPLANATION

Figure 19. Plot showing percentage of employees at businesses in the California tsunami-inundation zone with low and high visitor 

potential. %, percent.
30 Community Exposure to Tsunami Hazards in California

The percentage of employees in the tsunami-inundation 

zone at businesses with low visitor potential is high in several 

communities, such as Albany (100 percent), Carpinteria (81 

percent), Fort Bragg (81 percent), San Leandro (80 percent), 

Grover Beach (80 percent), and Oakland (76 percent) (fig. 

19). Tsunami outreach in communities with low-visitor 

businesses in the hazard zone could leverage local knowledge 

and reinforce what is being taught to residents. Outreach 

could be delivered through business meetings, neighborhood 

associations, and community fairs. Emergency managers and 

educators may need to further explore the types of businesses 

in the tsunami-inundation zone to determine if unique 

vulnerability issues exist in these workplaces. For example, 

hazardous material spills may complicate evacuations at a 

chemical-manufacturing plant, heavy machinery or other 

waterfront equipment could limit evacuations at a timber 

processing plant, and the seasonal aspects of the workforce 

could complicate preparedness planning at seafood 

processing plants and other businesses that vary throughout 

the year. Disruptions to road and rail networks due to 

tsunami inundation or debris also could negatively impact 

manufacturing businesses (including those outside of the 

tsunami-inundation zone) that rely on these routes to ship raw 

materials and finished goods. 

The percentage of employees in the tsunami-inundation 

zone at businesses with high visitor potential is high in other 

communities, such as Santa Monica (95 percent), Dana Point 

(90 percent), Laguna Beach (87 percent), Malibu (84 percent), 

Berkeley (80 percent), Santa Cruz (68 percent; fig. 1H, for 

example), and most of the communities in Orange and San 

Diego Counties (fig. 19). In these communities, successful 

tsunami-outreach efforts will require collaboration with the 

private sector to reach visitor and tourist populations. Tsunami 

evacuations may be more difficult in these communities 

because evacuees may be unaware of the tsunami threat 

and unaware of what to do in the event of a tsunami. In 

addition, communities with high numbers and concentrations 

of tourism-related businesses in tsunami-hazard zones are 

typically adjacent to beaches with high tourist populations or 

may host festivals or other community events at various times 

throughout the year. Emergency managers could coordinate 

with these tourist-related businesses and lifeguards to educate 

locals, employees, and tourists about tsunami preparedness 

during such events. 

Community-Support Businesses

To provide further insight on population dynamics in the 

various coastal communities, we used NAICS codes in the 

2011 Infogroup Employer Database to identify certain types 

of businesses that may attract additional people to tsunamiprone areas, including community-support businesses, 

dependent-care facilities, and public venues. The high number 

of businesses and the dynamic nature of populations at these 

locations preclude our ability to determine exact visitor counts 

at each business; therefore, discussions of these locations 

are limited to the number of venues and facilities. The first 

category—community support—includes businesses that 

attract significant populations throughout a workday because 

they provide basic necessities primarily to residents (although 

visitors may use them also). These community-support 

businesses include:

• Banks or credit unions;

• Civil or social organizations, including social clubs, 

after-school programs, and lodges;

• Large department stores, including wholesale warehouse stores and home improvement stores;

• Gas stations, including commercial and public filling 

stations and auto repair centers;

• Government offices, including Federal, State, and local 

government offices, police and fire departments, courts 

and legal offices, and international-affairs offices;

• Grocery stores;

• Libraries, including city, Federal, institutional, public, 

and state libraries;

• Mailing and shipping services, including U.S. Post 

Offices and commercial shipping facilities; and

• Religious organizations, such as churches, convents 

and monasteries, meditation centers, mosques, non-theistic places of worship, retreat houses, spiritual centers, 

synagogues, and other facilities associated with them 

(such as community centers). 

There are many businesses that primarily provide 

community support in the tsunami-inundation zone, including 

10 civil or social organizations, 43 large department stores, 

90 religious organizations, 19 libraries, 262 government 

offices, 83 banks and credit unions, 73 grocery stores, 68 gas 

stations, and 48 mail and shipping services (table 2; fig. 20). 

The highest numbers of community-support businesses in the 

tsunami-inundation zone are in the cities of Alameda, Long 

Beach, Oakland, Newport Beach, Crescent City, and Eureka. 

The majority of community-support businesses in the tsunamiinundation zone are government offices and banks or credit 

unions. 

Employees and local residents at community-support 

locations could be in danger if a tsunami were to occur during 

typical business hours (for example, from about 8 a.m. to 6 

p.m.). In addition, community services patrons may only be 

aware of tsunami threats from the perspective of their homes 

and therefore not fully aware of evacuation procedures or 

even tsunami potential when they are out running errands or 

attending a religious service. The presence of communitysupport businesses in the tsunami-inundation zone, however, 

also presents an outreach opportunity for emergency managers 

to work with employees of these businesses to educate local 
Variations in Community Exposure 31

Table 2. Amount and percentage of businesses in the tsunamiinundation zone of California.

[%, percent]

Business Categories Tsunami 

zone

Study 

area %

Community-support business

Community-support business (total) 696 1

Bank or credit union 83 1

Civil or social organization 10 1

Large department store 43 1

Gas station 68 2

Government office 262 2

Grocery store 73 1

Library 19 1

Mailing and shipping service 48 3

Religious organization 90 1

Dependent-care facility

Dependent-care facility (total) 694 1

Child services 62 1

Correctional institution 4 4

Elderly services 37 1

Homeless shelter 3 5

Medical center 3 1

Office of physicians or other medical personnel 513 1

School (K–12) 72 1

Public venue

Public venue (total) 576 4

College 17 2

Entertainment center 45 3

Marina 92 56

Museum 22 4

Overnight accommodation 288 5

Park or other outdoor venue 44 3

Recreational center 68 3

and nonresident populations. This could include promoting 

the use of internet-based mapping applications (for example, 

http://www.tsunami.ca.gov or http://myhazards.calema.ca.gov) 

where people can enter addresses (for example, homes, 

workplace, or markets) to determine if they are in tsunamiprone areas during the course of their day.

Dependent-Care Facilities 

Dependent-care facilities contain individuals who would 

require assistance to evacuate and include:

•	 Medical centers, including hospitals, psychiatric and 

substance abuse hospitals, mental health services and 

psychiatric treatment facilities, and clinics;

•	 Elderly services, including adult-care facilities, hospices, 

nursing homes, rest homes, retirement communities, adult 

homes, senior citizens services, residential care homes, 

and adult daycare centers;

•	 Child services, including group homes, foster care, childcare centers, preschools and nursery schools (both public 

and private), and after-school recreational facilities; 

•	 Schools, including religious schools, public and private 

schools, schools with special academics, and homeschooling centers; 

•	 Homeless shelters;

•	 Correctional institutions, including State and Federal 

facilities; and

•	 Office of physicians or other medical personnel, such 

as general-practice doctors, pediatricians, podiatrists, 

obstetricians and gynecologists, chiropractors, and 

acupuncturists.1

On the basis of 2011 economic data, a substantial 

number of dependent-population facilities are in the tsunamiinundation zone, including 72 schools and educational 

facilities, 62 child service facilities, 37 elderly facilities, 513 

office of physicians or other medical personnel, 3 medical 

centers, 3 homeless shelters, and 4 correctional institutions 

(table 2; fig. 21). The highest number of dependentpopulation facilities in the tsunami-inundation zone is in the 

City of Alameda, and they include schools, elderly-service 

facilities, and child-service facilities. Other communities with 

numerous dependent-care facilities in the tsunami-inundation 

zone include Long Beach, Emeryville, Oakland, Larkspur, 

Mill Valley, and Huntington Beach (with the primary type 

being offices of physicians in each community). Additional 

evacuation planning may be required in communities with 

high numbers of dependent-population facilities because 

of the limited mobility of certain groups at these facilities, 

such as those in schools and nursing homes. Also, parents 

may attempt to enter tsunami-prone areas to retrieve 

children from schools and daycare centers or adult children 

may attempt to enter tsunami-prone areas to retrieve their 

parents from elderly care facilities, which present additional 

evacuation issues for facility managers. In addition to unique 

evacuation and relief issues, many dependent-population 

facilities represent critical social services that, if lost, could 

slow community recovery following an extreme event. For 

example, the loss of daycare centers could keep parents at 

home, thereby slowing business recovery.

1

Not all medical professions were inventoried in this analysis of dependent populations. We only focused on identifying offices where we believed 

patients might have greater difficulty evacuating due to potential limited 

mobility, such as children, pregnant women, or patients with foot ailments. 

For example, we did not inventory psychologist or dentist offices, because we 

felt a patient’s mobility at these locations would not be significantly impaired.
32 Community Exposure to Tsunami Hazards in California

Number of community-support businesses 

in the tsunami-inundation zone

0 40 80

Number of community-support businesses 

in the tsunami-inundation zone

Sonoma Co.

Napa County

San Francisco Co.

San Mateo

County

Contra 

Costa

County

Humbolt

County

Santa Clara

County

Mendocino

County

Del Norte

County

Marin

County

Alameda

County

Solano

County

Crescent City

Remaining land

Trinidad

Arcata

Eureka

Ferndale

Remaining land

Fort Bragg

Point Arena

Remaining land

Remaining land

Novato

San Rafael

Larkspur

Mill Valley

Belvedere

Sausalito

Remaining land

Remaining land

Vallejo

Benicia

Remaining land

Martinez

Hercules

Pinole

Richmond

Remaining land

Albany

Berkeley

Emeryville

Oakland

Alameda

San Leandro

Hayward

Union City

Fremont

Newark

Remaining land

San Jose

Sunnyvale

Mountain View

Palo Alto

Remaining land

San Francisco

East Palo Alto

Menlo Park

Redwood City

San Carlos

Foster City

San Mateo

Burlingame

Millbrae

South San Francisco

Brisbane

Daly City

Pacifica

Half Moon Bay

Remaining land

San Diego

County

Ventura

County

Orange

County

Monterey

County

Santa Cruz

County

Santa Barbara

County

Los Angeles

County

San Luis Obispo

County

Santa Cruz

Capitola

Remaining land

Marina

Seaside

Sand City

Monterey

Pacific Grove

Carmel-by-the-Sea

Remaining land

Morro Bay

Pismo Beach

Grover Beach

Remaining land

Goleta

Santa Barbara

Carpinteria

Remaining land

San Buenaventura (Ventura)

Oxnard

Port Hueneme

Remaining land

Malibu

Los Angeles

Santa Monica

El Segundo

Manhattan Beach

Hermosa Beach

Redondo Beach

Torrance

Palos Verdes Estates

Rancho Palos Verdes

Long Beach

Avalon

Remaining land

Seal Beach

Westminster

Huntington Beach

Costa Mesa

Newport Beach

Laguna Beach

Dana Point

San Clemente

Remaining land

Oceanside

Carlsbad

Encinitas

Solana Beach

Del Mar

San Diego

Coronado

National City

Chula Vista

Imperial Beach

Remaining land

0 40 80

Library

Grocery store

Government office

Gas station

Department store

Civil or social organization

Bank or credit union

Mailing and shipping

Religious organization

EXPLANATION

Figure 20. Plot showing number of community-support businesses and organizations in the California tsunami-inundation zone.
Variations in Community Exposure 33

Number of dependent-care facilities in tsunami-inundation zone Number of dependent-care facilities in tsunami-inundation zone

0 50 100 150

School

Office of physicians

Medical center

Homeless shelter

Elderly service

Correctional institution

Child service

0 50 100 150

Sonoma Co.

Napa County

San Francisco Co.

San Mateo

County

Contra 

Costa

County

Humbolt

County

Santa Clara

County

Mendocino

County

Del Norte

County

Marin

County

Alameda

County

Solano

County

Crescent City

Remaining land

Trinidad

Arcata

Eureka

Ferndale

Remaining land

Fort Bragg

Point Arena

Remaining land

Remaining land

Novato

San Rafael

Larkspur

Mill Valley

Belvedere

Sausalito

Remaining land

Remaining land

Vallejo

Benicia

Remaining land

Martinez

Hercules

Pinole

Richmond

Remaining land

Albany

Berkeley

Emeryville

Oakland

Alameda

San Leandro

Hayward

Union City

Fremont

Newark

Remaining land

San Jose

Sunnyvale

Mountain View

Palo Alto

Remaining land

San Francisco

East Palo Alto

Menlo Park

Redwood City

San Carlos

Foster City

San Mateo

Burlingame

Millbrae

South San Francisco

Brisbane

Daly City

Pacifica

Half Moon Bay

Remaining land

San Diego

County

Ventura

County

Orange

County

Monterey

County

Santa Cruz

County

Santa Barbara

County

Los Angeles

County

San Luis Obispo

County

Santa Cruz

Capitola

Remaining land

Marina

Seaside

Sand City

Monterey

Pacific Grove

Carmel-by-the-Sea

Remaining land

Morro Bay

Pismo Beach

Grover Beach

Remaining land

Goleta

Santa Barbara

Carpinteria

Remaining land

San Buenaventura (Ventura)

Oxnard

Port Hueneme

Remaining land

Malibu

Los Angeles

Santa Monica

El Segundo

Manhattan Beach

Hermosa Beach

Redondo Beach

Torrance

Palos Verdes Estates

Rancho Palos Verdes

Long Beach

Avalon

Remaining land

Seal Beach

Westminster

Huntington Beach

Costa Mesa

Newport Beach

Laguna Beach

Dana Point

San Clemente

Remaining land

Oceanside

Carlsbad

Encinitas

Solana Beach

Del Mar

San Diego

Coronado

National City

Chula Vista

Imperial Beach

Remaining land

EXPLANATION

Figure 21. Plot showing number of dependent-population facilities in the California tsunami-inundation zone.
34 Community Exposure to Tsunami Hazards in California

Public Venues

Tourists are another significant population in coastal 

communities and can often outnumber residents and 

employees in tsunami-prone areas (Wood and Good, 2004). 

No consistent census count for tourists exists; therefore, the 

locations of public venues are used as an indicator of tourist 

populations, while acknowledging that local residents are 

also present at public venues. Businesses that likely attract 

both residents and nonresidents are considered public venues 

and are identified using NAICS codes in the 2011 Infogroup 

Employer Database. Public venues include:

•	 Entertainment centers, including aquariums, botanical 

gardens, casinos, theaters (including live and cinematic), 

and amusement parks (fig. 1H, for example);

•	 Colleges, including community colleges, private universities, and public universities (fig. 14B, for example);

•	 Marinas, including recreational and fishing, vessel repair 

and storage, and yacht clubs (fig. 1C, for example);

•	 Museums, including art, history, and technology museums; 

•	 Overnight accommodations, including hotels, inns, 

resorts, hostels, cabin rentals, bed and breakfasts, and 

student housing;

•	 Park or other outdoor venues, including parks (fig. 1G,

for example), amphitheaters, race tracks, sports stadiums, 

zoos, and fairgrounds; and

•	 Recreational centers, including sports parks, gyms, golf 

courses, and family fun centers.

Many public venues are in the tsunami-inundation zone, 

including 288 overnight-tourist accommodations, 44 parks or 

other outdoor venues, 22 museums, 17 colleges, 92 marinas, 68 

recreational centers, and 45 entertainment centers (table 2; fig. 22). 

The highest numbers of public venues in the tsunami-inundation 

zone are in the cities of San Diego, Los Angeles, Oakland, Eureka, 

and Santa Cruz. The majority of public venues in the tsunamiinundation zone are overnight accommodations. Large numbers 

of visitors could be in danger if a tsunami were to occur during 

a high-occupancy time (for example, holidays or weekends). 

Visitors may not be fully aware of evacuation procedures or 

even the potential for tsunamis if they are coming from areas 

with no history of tsunamis. In addition, public servants, such as 

emergency managers, might not be working on weekends and 

holidays, further complicating emergency-response activities 

at these times. The presence of public venues in the tsunamiinundation zone, however, also presents an outreach opportunity 

for emergency managers to work with owners and employees of 

these public venues to educate local and tourist populations.

The number of public venues and facilities in tsunami-prone 

areas of each community provides some insight about dynamic 

populations but does not capture the range in magnitudes of 

populations at these sites. Therefore, these counts should serve 

as starting points for discussion and further studies about highoccupancy public venues. Examples of high-occupancy public 

venues in the tsunami-inundation zone include: 

•	 Monterey Bay Aquarium, where daily visitor attendance 

can exceed 4,931 people (Jeffries, 2011); 

•	 Santa Cruz Beach Boardwalk which attracts approximately three million visitors each year (fig. 1H) (Season 

Pass/Group Sales Office, oral commun., January 30, 

2012);

•	 Public piers with high-volume tourist populations in Santa 

Monica, Redondo Beach, Santa Barbara, and Pismo Beach;

•	 The Catalina Casino in Avalon, which includes a 1,184-

seat theater and a ballroom with a capacity of 1,400 

people (Visit Catalina Island, 2012; fig. 23); 

•	 Waterfronts that serve as ports of call for cruises, such as 

the City of Avalon on Catalina Island that receives tourists 

from five international cruise lines, including as many as 

2,000 passengers on a weekly basis from one ship (Catalina Island Chamber of Commerce and Visitors Bureau, 

2012; fig. 23); and 

•	 Terminals for cruise ships, including the World Cruise 

Center at the Port of Los Angeles that serves 12 different 

cruise lines (Pacific Cruise Ship Terminals, 2012) and 

the Long Beach Cruise Terminal that primarily serves 

Carnival cruises, that together see more than 300 cruise 

departures every year (Cruisetimetables.com, 2012).

Park and Beach Visitors

In addition to public venues, residents and tourists are drawn 

to tsunami-prone areas by the multiple recreational opportunities 

along the 1,200-mile California coastline (Visit California, 2012). 

Substantial numbers of visitors are attracted to city, county, State, 

and national beaches and coastal parks, especially in summer 

months (fig. 24A, for example). The coast is also a gateway to 

boating activities, such as sailing in San Francisco Bay (fig. 24B) 

or anchoring in Avalon Bay (fig. 23). Estimating the magnitude 

of population exposure to tsunamis for these groups is difficult 

given their dynamic nature. The boating community is especially 

difficult given the large range in their locations throughout the 

day and the uncertainty in their points of entry to and departure 

from waterways. For example, sailboats in San Francisco Bay 

could have originated from nearby marinas in the bay or from 

marinas elsewhere, such as Half Moon Bay or other points on the 

U.S. West Coast. Because the California maritime community is 

vulnerable to even minor tsunamis, the State tsunami program 

has an active boater-preparedness program (California Geological 

Survey, 2012). Gauging the extent of maritime activity in coastal 

California waters is beyond the scope of this assessment, and 

subsequent discussion is limited to visitors to beaches and parks. 

Analysis of visitor data from State of California parks 

(California State Parks, 2010) and national parks (National 
Variations in Community Exposure 35

Number of public venues in tsunami-inundation zone

0 20 40

Number of public venues in tsunami-inundation zone

Sonoma Co.

Napa County

San Francisco Co.

San Mateo

County

Contra 

Costa

County

Humbolt

County

Santa Clara

County

Mendocino

County

Del Norte

County

Marin

County

Alameda

County

Solano

County

Crescent City

Remaining land

Trinidad

Arcata

Eureka

Ferndale

Remaining land

Fort Bragg

Point Arena

Remaining land

Remaining land

Novato

San Rafael

Larkspur

Mill Valley

Belvedere

Sausalito

Remaining land

Remaining land

Vallejo

Benicia

Remaining land

Martinez

Hercules

Pinole

Richmond

Remaining land

Albany

Berkeley

Emeryville

Oakland

Alameda

San Leandro

Hayward

Union City

Fremont

Newark

Remaining land

San Jose

Sunnyvale

Mountain View

Palo Alto

Remaining land

San Francisco

East Palo Alto

Menlo Park

Redwood City

San Carlos

Foster City

San Mateo

Burlingame

Millbrae

South San Francisco

Brisbane

Daly City

Pacifica

Half Moon Bay

Remaining land

San Diego

County

Ventura

County

Orange

County

Monterey

County

Santa Cruz

County

Santa Barbara

County

Los Angeles

County

San Luis Obispo

County

Santa Cruz

Capitola

Remaining land

Marina

Seaside

Sand City

Monterey

Pacific Grove

Carmel-by-the-Sea

Remaining land

Morro Bay

Pismo Beach

Grover Beach

Remaining land

Goleta

Santa Barbara

Carpinteria

Remaining land

San Buenaventura (Ventura)

Oxnard

Port Hueneme

Remaining land

Malibu

Los Angeles

Santa Monica

El Segundo

Manhattan Beach

Hermosa Beach

Redondo Beach

Torrance

Palos Verdes Estates

Rancho Palos Verdes

Long Beach

Avalon

Remaining land

Seal Beach

Westminster

Huntington Beach

Costa Mesa

Newport Beach

Laguna Beach

Dana Point

San Clemente

Remaining land

Oceanside

Carlsbad

Encinitas

Solana Beach

Del Mar

San Diego

Coronado

National City

Chula Vista

Imperial Beach

Remaining land

0 20 40

College

Entertainment center

Marina

Museum

Overnight 

accommodation

Park

Recreational center

EXPLANATION

Figure 22. Plot showing number of public venues in the California tsunami-inundation zone.
36 Community Exposure to Tsunami Hazards in California

Figure 23. Photograph of Avalon Harbor on Catalina Island, California (photograph from Catalina Island Chamber of Commerce and 

Visitors Bureau, 2012).

Figure 24. Photographs of recreationists in tsunamihazard zones, including (A) beach visitors to Huntington 

Beach (City of Huntington Beach, 2012) and (B) boaters 

in San Francisco Bay (image from Daniel Austin Hoherd, 

2012, used with permission).

A

B
Variations in Community Exposure 37

Park Service, 2011) suggests that 95 parks are in the California 

tsunami-inundation zone (appendix 2). For the 2009–2010 

fiscal year, the sum of annual average visitors to the 95 

coastal parks was 60,707,359 people. Assuming an equal 

distribution of visitors on every day of the year, this equates 

to 166,322 day-use visitors to coastal State and national parks 

on average every day. This number is low because attendance 

is not equally distributed throughout the year and there will 

be seasonal peaks in park attendance (for example, summer 

months and holidays). The highest annual average of dayuse visitors at national and State parks was for Golden Gate 

National Recreation Area and Sonoma Coast State Park 

(14,823,791 and 3,068,517 visitors per year, respectively).

0 10 50

Del Norte (county)

Humboldt (county)

Mendocino (county)

Marin (county)

San Francisco (county)

San Mateo (county)

Santa Cruz (county)

Santa Cruz (city)

Capitola (city)

Monterey (county)

Morro Bay (city)

Pismo Beach (city)

San Luis Obispo (county)

Santa Barbara (county)

Santa Barbara (city)

Ventura (county)

Port Hueneme (city)

Los Angeles (city)

Los Angeles (county)

Long Beach (city)

Seal Beach (city)

Huntington Beach (city)

Newport Beach (city)

Laguna Beach (city)

San Clemente (city)

Orange (county)

Oceanside (city)

Encinitas (city)

Solana Beach (city)

Del Mar (city)

San Diego (city)

Coronado (city)

Imperial Beach (city)

San Diego (county)

Annual attendance (2010), in millions, at beach or park

20 30 40 60

City or county

State

National

EXPLANATION

Figure 25. Plot of annual average number of visitors (in millions) 

to coastal California city and county beaches, State parks, and 

National Park Service locations grouped by city and county 

jurisdictions. Raw visitor numbers for specific locations can be 

found in appendix 2.

National and State parks are coded by the primary county 

in which they are located to gauge the potential impact to 

communities. Although the State and national park visitors are 

outside of county jurisdictions, grouping the parks by county 

provides insight on where there may be significant tourist 

issues after a catastrophic tsunami. For example, many State 

and national park visitors likely go to nearby communities 

to eat meals or to shop, and these visitors will add to the 

at-risk population that may need to evacuate during a tsunami 

warning. In addition, when a tsunami alert is issued by the 

National Oceanic and Atmospheric Administration (NOAA), 

county public-safety officials will be called on to evacuate 

populations at coastal parks. Clustering the number of visitors 

of coastal parks to surrounding counties (fig. 25) reveals that 

the majority of national and State park visitors are going to 

parks in San Francisco, Orange, San Diego, San Luis Obispo, 

and Marin Counties. Therefore, in addition to dealing with 

residents and employees within the tsunami-inundation zones 

of their communities, cities like San Francisco may have 

significant numbers of tourists that are visiting nearby parks 

when a tsunami occurs.

Attendance numbers for city and county beaches were 

retrieved from the United States Lifesaving Association 

(USLA) where they are collected annually from beach 

lifeguards on a volunteer basis. Beach attendance is defined 

by the USLA as the “people recreating in the water or on the 

sand, and at adjacent picnic areas, parking lots, recreation 

concessions and bike paths...[but] does not include people 

that merely transit on bikes or in cars” (United States 

Lifesaving Association, 2012). Because estimates are provided 

by lifeguards on a volunteer basis, not all beaches on the 

California coast have data for every year or at all in many 

cases. Data on annual beach attendance were compiled for 

2010 and not 2011 because (1) 2010 data contained a greater 

number of beaches and (2) it allows for comparisons with 

residential data in the 2010 Census population count. This 

analysis yielded 27 beach jurisdictions that included city and 

county properties and were primarily in southern California 

(the City of Santa Cruz being the northern-most unit). Data 

were not available for beaches north of Santa Cruz, suggesting 

that they do not have lifeguards or that the lifeguards there do 

not participate in the national data-collection effort.

Statistics on 2010 annual beach attendance suggest that 

California city and county beaches attract a substantial number 

of visitors (fig. 25; appendix 2). More than 140 million 

people visited our subset of 27 California beach jurisdictions 

in 2010, with the greatest number visiting beaches in the 

County of Los Angeles (57 million visitors) and the City of 

San Diego (24 million visitors). Other beaches with relatively 

high beach attendance are those in Long Beach (6.6 million), 

Huntington Beach (8.0 million), Newport Beach (7.1 million), 

Orange County (6.7 million), Laguna Beach (3.9 million), 

and Oceanside (3.8 million). This suggests that California city 

and county beaches attract more visitors than the combined 

number of visitors to State and national parks (140 million per 

year compared to 61 million per year reported earlier). 
38 Community Exposure to Tsunami Hazards in California

Assuming an equal distribution of visitors on every day 

of the year, an annual attendance of 140,452,280 visitors 

translates to 384,801 day-use visitors to city and county 

beaches in southern California on average every day. This 

annual average is greater than the total number of residents 

in the tsunami-inundation zone for the entire State (267,347 

residents). Actual daily attendance at city and county beaches 

is even greater because beach attendance is not uniform 

throughout the year or among the various beaches. In a study 

of annual beach attendance of 75 southern California beaches 

in 2007, Dwight and others (2007) conclude that 53 percent of 

all visits occurred in summer months and that 48 percent of all 

visits throughout the year occurred on weekends (27 percent 

on Saturdays and 21 percent on Sundays). Therefore, after 

accounting for this variability in beach attendance and using 

these percentages, the number of people on city and county 

beaches in southern California is estimated to range from 

92,699 visitors on a Tuesday in February to 1,660,989 visitors 

on a Saturday in July2

. 

Peak attendance on holiday weekends can be even 

higher than the daily beach estimates. For example, beach 

attendance on Sunday, July 4, 2010, was 584,750 people for 

City of San Diego beaches (City of San Diego Lifeguard 

Services, oral commun., June 21, 2012) and 1,165,550 people 

for Los Angeles County beaches (Los Angeles County Fire 

Department, Lifeguard Division, oral commun., June 21, 

2012). Using annual attendance values from USLA (2012) and 

percentages described earlier in Dwight and others (2007), 

daily attendance in 2010 would be estimated to be 275,587 

people on San Diego beaches and 656,167 people on Los 

Angeles County beaches, which is approximately 47 percent 

and 56 percent, respectively, of the actual attendance estimated 

by lifeguards on that day. Therefore, peak beach attendance 

on high-volume holidays like July 4th weekend could be 

higher than the 1.7 million estimated earlier for city and 

county beaches. If we assume the actual peak daily attendance 

on other beaches was also 1.8 times higher than estimated 

attendance (as was the case with Los Angeles County beaches 

for July 4th weekend in 2010), then an estimate of 2.9 million 

people on southern California beaches on a day during a 

summer holiday is plausible. 

Regardless if daily beach attendance is 2 or 3 million 

people on peak holidays, both values are substantially greater 

than the total number of residents in the tsunami-inundation 

zone. Beach visitors may be residents and double counting 

is sure to exist. However, even with the potential for some 

double counting, data suggest beach visitors substantially 

exceed residential populations in the tsunami-inundation zone, 

particularly during summer months.

2

This is based on the 2010 annual beach attendance total of 140,452,280 

visitors for the 27 beaches in our analysis. The low estimate is based on 3.3 

percent of visitors attending in February, 8 percent are on Tuesdays, and there 

being 4 Tuesdays in February in 2010. The upper estimate is based on 21.9 

percent of visitors attending in July, 27 percent of these visitors are associated 

with Saturdays, and there being five Saturdays in July of 2010. 

Composite Indices of Community 

Exposure

We developed two composite indices to compare 

community exposure from tsunamis for the 114 geographic 

units (94 incorporated cities, and the remaining land in the 20 

counties). An amount index was derived for each geographic 

unit from the amount of developed land and the number of 

residents, employees, public venues, dependent-population 

facilities, community-support businesses, and beach and park 

visitors. A percentage index was derived for each geographic 

unit from the percentage of the same categories relative to 

the total amount of each within a community, except for the 

percentage of total beach visitors within a community, which 

was excluded because it was not applicable. Therefore, the 

amount index includes seven variables and the percentage 

index includes six variables.

Each composite index was created by normalizing values 

to the maximum value found within a category. Normalizing 

data to maximum values creates a common data range of 

zero to one for all categories and is a simple approach for 

comparing disparate datasets. The normalized values in each 

community were added, resulting in scores from zero to seven 

for the amount index and from zero to six for the percentage 

index (fig. 26). The two unitless indices allow us to compare 

the relative exposure levels for the 114 geographic units at 

regional or State levels. Because they are relative metrics, 

the numbers do not provide much meaning for individual 

communities. Understanding tsunami exposure within an 

individual community is better served by looking at the actual 

data for a jurisdiction.

Figure 26 illustrates the two composite indices for the 

114 areas, where higher values indicate higher amounts or 

percentages. The bar graph representing the amount of assets 

is reversed on the vertical axis in figure 26 to facilitate easier 

comparisons of the two values in individual communities. 

Values for both indices increase as the bar extends away 

from the central line. For example, the City of Alameda has 

the highest composite amount value (4.95), indicating that 

this community consistently has one of the highest number of 

populations in the tsunami-inundation zone. The community 

of Belvedere has the highest composite percentage value 

(5.19), indicating it has the highest percentage of populations 

in the tsunami-inundation zone for each of the six categories. 

Only the City of Alameda has high composite values for 

both the amount and percentage of populations in tsunamiprone areas. Other communities with fairly equal (but much 

lower than Alameda) amount and percentage values include 

Eureka, Santa Cruz, Oxnard, and Newport Beach. The 

remaining communities either have high amount but low 

percentage values (for example, Oakland, Los Angeles, Long 

Beach, Huntington Beach, San Francisco, and San Diego) 

or low amount but high percentage values (for example, 

Crescent City, Belvedere, Sausalito, Emeryville, Seal Beach, 

and Coronado).
Composite Indices of Community Exposure 39

Figure 26. Plot comparing normalized indices for the amount and percentage of community assets (developed land, residents,

employees, public venues, dependent-population facilities, community-service businesses, and beach visitors) for communities with land 

in the California tsunami-inundation zone. The percentage index does not include beach attendance values because it is not applicable.

Sum of normalized indices Sum of normalized indices

Amounts Percentages

246 0 2 4 6

Amounts Percentages

246 0 2 4 6

Sonoma Co.

Napa County

San Francisco Co.

San Mateo

County

Contra 

Costa

County

Humbolt

County

Santa Clara

County

Mendocino

County

Del Norte

County

Marin

County

Alameda

County

Solano

County

Crescent City

Remaining land

Trinidad

Arcata

Eureka

Ferndale

Remaining land

Fort Bragg

Point Arena

Remaining land

Remaining land

Novato

San Rafael

Larkspur

Mill Valley

Belvedere

Sausalito

Remaining land

Remaining land

Vallejo

Benicia

Remaining land

Martinez

Hercules

Pinole

Richmond

Remaining land

Albany

Berkeley

Emeryville

Oakland

Alameda

San Leandro

Hayward

Union City

Fremont

Newark

Remaining land

San Jose

Sunnyvale

Mountain View

Palo Alto

Remaining land

San Francisco

East Palo Alto

Menlo Park

Redwood City

San Carlos

Foster City

San Mateo

Burlingame

Millbrae

South San Francisco

Brisbane

Daly City

Pacifica

Half Moon Bay

Remaining land

San Diego

County

Ventura

County

Orange

County

Monterey

County

Santa Cruz

County

Santa Barbara

County

Los Angeles

County

San Luis Obispo

County

Santa Cruz

Capitola

Remaining land

Marina

Seaside

Sand City

Monterey

Pacific Grove

Carmel-by-the-Sea

Remaining land

Morro Bay

Pismo Beach

Grover Beach

Remaining land

Goleta

Santa Barbara

Carpinteria

Remaining land

San Buenaventura (Ventura)

Oxnard

Port Hueneme

Remaining land

Malibu

Los Angeles

Santa Monica

El Segundo

Manhattan Beach

Hermosa Beach

Redondo Beach

Torrance

Palos Verdes Estates

Rancho Palos Verdes

Long Beach

Avalon

Remaining land

Seal Beach

Westminster

Huntington Beach

Costa Mesa

Newport Beach

Laguna Beach

Dana Point

San Clemente

Remaining land

Oceanside

Carlsbad

Encinitas

Solana Beach

Del Mar

San Diego

Coronado

National City

Chula Vista

Imperial Beach

Remaining land

Developed land

Residents

Employees

Community support

Dependent care

Public venues

Beaches and parks

EXPLANATION
40 Community Exposure to Tsunami Hazards in California

A frequency histogram depicting the distribution of 

composite amount and percentage values illustrates the 

relative exposure of the 94 communities and remaining 

land of the 20 counties (fig. 27). The x axis shows the 

relative composite scores in 0.5 increments, and the y axis 

notes the number of communities for each category. Most 

communities have scores of 0 to 1 for relative composite 

amount, indicating that they have considerably fewer people 

and societal assets in tsunami-prone areas than the cities of 

Alameda, Oakland, or Long Beach. The composite percentage 

values are distributed similarly, where most communities 

have scores of 0 to 1 across the multiple ranges and the cities 

of Belvedere, Alameda, Crescent City, and Emeryville are 

outliers for composite percentage values. 

We calculated a final score for each of the 114 

geographic units by normalizing the amount and percentage 

indices to maximum values (yielding a common data range 

between zero and one for the two indices) and then adding the 

two indices, resulting in values ranging between zero and two 

(fig. 28). Normalizing the two indices before adding them is 

needed to eliminate weighting bias between the indices; this 

bias can occur because of differences in the distribution of 

values within each index. Communities with the highest final 

scores have the highest numbers and percentages of people in 

the tsunami-inundation zone. Although not observed, a final 

score of two would indicate that a community always had the 

highest number and percentage of people and assets in the 

tsunami-inundation zone for each of the six categories. 

This approach results in the cities of Alameda, 

Belvedere, and Crescent City having the highest relative 

exposure to tsunamis according to the areas on the California 

coast with mapped tsunami-inundation zones (fig. 29). 

Alameda’s vulnerability is due to both high numbers and 

percentages of assets in tsunami-prone areas, whereas the 

vulnerability of Belvedere and Crescent City has more to 

do with the high percentage of their assets in tsunami-prone 

0

10

20

30

40

50

60

70

80

90

Number of communities

Sum of normalized exposure indices

0.0–0.5

0.5–1.0

1.0–1.5

1.5–2.0

2.0–2.5

2.5–3.0

3.0–3.5

3.5–4.0

4.0–4.5

4.5–5.0

5.0–5.5

Amount of populations

Percentage of populations

EXPLANATION

Oakland Alameda

Belvedere

Long Beach

Crescent City and Emeryville

Figure 27. Frequency histogram of the sum of

normalized exposure indices for communities in the 

California tsunami-inundation zone. The x axis shows the 

relative composite scores in 0.5 increments and the y axis 

notes the number of communities for each category.

areas. The next set of communities in this relative ranking 

(Emeryville, Oakland, Long Beach, Seal Beach, Huntington 

Beach, Newport Beach, Eureka, Sausalito, and Los Angeles) 

have high relative exposure to tsunami hazards (from 0.66 

to 0.96) due to a mixture of high percentages and amounts 

of people and assets in the hazard zone. Communities with 

similar percentages (for example, Emeryville and Seal Beach) 

may suffer comparable impacts, regardless of city size, 

whereas the impact on communities with similar amounts 

of people and assets in the tsunami-inundation zone may 

vary depending on their size and therefore their available 

resources. For example, although the cities of Los Angeles 

and Newport Beach have similar numbers of residents in the 

tsunami-inundation zone (15,568 and 17,468, respectively), 

the community percentages vary substantially (0 and 21 

percent, respectively) and the resources available in Los 

Angeles to prepare for and respond to a tsunami will likely be 

greater than in Newport Beach. The remaining communities 

with composite values approximately 0.5 and less (such as 

Coronado, San Diego, and Mill Valley) have relatively much 

less in the tsunami-inundation zone and the loss of these 

assets may have less impact than in other communities. 

Comparing the amount and percentage of various 

populations in tsunami-prone areas of the communities is 

a first step in discussing societal vulnerability but is not 

an exhaustive statement on the topic because variations in 

individual or community sensitivity and adaptive capacity are 

not fully addressed (Turner and others, 2003). The ability of 

a community to adapt to future tsunamis, respond to an event, 

and recover from an event lowers a community’s vulnerability 

to extreme events. For example, if two communities have 

similar population distributions in tsunami-prone areas, 

but one has a tsunami education program, a well-rehearsed 

evacuation plan, shorter travel times to high ground, and a 

post-disaster recovery plan, then that community is assumed 

to have greater adaptive capacity that should result in more 
Composite Indices of Community Exposure 41

Sum of normalized composite values

0.0 1.0 2.0 0.0 1.0 2.0

Sum of normalized composite values

Sonoma Co.

Napa County

San Francisco Co.

San Mateo

County

Contra 

Costa

County

Humbolt

County

Santa Clara

County

Mendocino

County

Del Norte

County

Marin

County

Alameda

County

Solano

County

Crescent City

Remaining land

Trinidad

Arcata

Eureka

Ferndale

Remaining land

Fort Bragg

Point Arena

Remaining land

Remaining land

Novato

San Rafael

Larkspur

Mill Valley

Belvedere

Sausalito

Remaining land

Remaining land

Vallejo

Benicia

Remaining land

Martinez

Hercules

Pinole

Richmond

Remaining land

Albany

Berkeley

Emeryville

Oakland

Alameda

San Leandro

Hayward

Union City

Fremont

Newark

Remaining land

San Jose

Sunnyvale

Mountain View

Palo Alto

Remaining land

San Francisco

East Palo Alto

Menlo Park

Redwood City

San Carlos

Foster City

San Mateo

Burlingame

Millbrae

South San Francisco

Brisbane

Daly City

Pacifica

Half Moon Bay

Remaining land

San Diego

County

Ventura

County

Orange

County

Monterey

County

Santa Cruz

County

Santa Barbara

County

Los Angeles

County

San Luis Obispo

County

Santa Cruz

Capitola

Remaining land

Marina

Seaside

Sand City

Monterey

Pacific Grove

Carmel-by-the-Sea

Remaining land

Morro Bay

Pismo Beach

Grover Beach

Remaining land

Goleta

Santa Barbara

Carpinteria

Remaining land

San Buenaventura (Ventura)

Oxnard

Port Hueneme

Remaining land

Malibu

Los Angeles

Santa Monica

El Segundo

Manhattan Beach

Hermosa Beach

Redondo Beach

Torrance

Palos Verdes Estates

Rancho Palos Verdes

Long Beach

Avalon

Remaining land

Seal Beach

Westminster

Huntington Beach

Costa Mesa

Newport Beach

Laguna Beach

Dana Point

San Clemente

Remaining land

Oceanside

Carlsbad

Encinitas

Solana Beach

Del Mar

San Diego

Coronado

National City

Chula Vista

Imperial Beach

Remaining land

EXPLANATION

Amount of populations

Percentage of populations

Figure 28. Plot showing sum of normalized amount and percentage indices for communities with land in the California tsunamiinundation zone. Communities with the highest final scores have the highest numbers and percentages of people and assets in the 

tsunami-inundation zone. Although not observed, a final score of two would indicate that a community always had the highest number 

and percentage of people and assets in the tsunami-inundation zone for each of the six categories.
42 Community Exposure to Tsunami Hazards in California

Figure 29. Photographs of communities considered to have high relative 

exposure to tsunamis, including (A) Alameda (Aerial photograph of Alameda 

Island, Image ID: AHLB3931, courtesy of aerialarchives.com), (B) Crescent 

City (image from Adelman and Adelman, 2010, used with permission), and (C) 

Belvedere (Aerial photograph of Belvedere, image ID: AHLB6747, courtesy of 

aerialarchives.com).

efficient response operations and shorter recovery 

times after the extreme event. Despite similar 

population distributions, the same extreme natural 

event would mean a short-term crisis in the more 

resilient community and a longer-term disaster in 

the less-resilient community. 

The pre-event wealth of households and the 

community as a whole also will influence their 

adaptive capacity and, therefore, their overall 

vulnerability to tsunamis. Wealth influences one’s 

ability to absorb losses and recover more quickly 

because it provides for greater access to resources 

for mitigation, preparedness, and recovery (Cutter 

and others, 2003). On the basis of 2010 U.S. Census 

data, there is a wide range in median household 

incomes in California coastal communities, from 

$26,612 in Crescent City in northern California 

to $163,542 in Palos Verde Estates in southern 

California. The average median household income 

is $75,182, which is higher than the U.S. median 

household income of $51,914 (U.S. Census Bureau, 

2012). The relations among median household 

income of the study-area communities (independent 

variable) and the composite amount or community 

percentages of populations in tsunami-hazard 

zones (dependent variables) are poorly correlated 

(R2

 values of 0.043 and 0.0005, respectively). This 

means wealthier communities were not more likely 

to have greater or fewer populations in the tsunamihazard zones than less wealthier communities. 

However, the variations in wealth along the 

California coastline will likely influence the 

adaptive capacity and long-term resilience of the 

exposed populations in the various communities.

Potential follow-up studies on community 

vulnerability to tsunami hazards in California could 

focus on the adaptive capacity of communities with 

regard to their ability to prepare for, respond to, and 

recover from damaging tsunamis. The current study 

offers insight into the magnitude of population 

exposure in the California tsunami-inundation zone 

and next steps could focus on the ability of these 

individuals, as well as the managers and officials 

responsible for public safety, to manage and 

hopefully reduce their tsunami risks. For example, 

a gap analysis of local capabilities and capacities 

could provide emergency managers with a blueprint 

for where additional training may be warranted. 

Scenarios could be created to estimate population, 

economic, and infrastructure losses from specific 

tsunami sources to help guide local decision making 

(for example, U.S. Geological Survey, 2012). 

Additional insight on the sensitivity and 

adaptive capacity of at-risk individuals is also 

important, because survival from near-field 

tsunami threats, such as the Cascadia Subduction 

A

B

C
Acknowledgments 43

Zone in northern California or local landslides in southern 

California, is largely a function of individuals educating and 

preparing themselves to recognize natural cues and self-evacuate 

to higher ground. Perception studies and evacuation drills could 

be conducted to determine if at-risk individuals are able to 

recognize natural cues of tsunamis and self-evacuate. Evacuation 

modeling could be performed to assess the likelihood of successful 

evacuations to naturally occurring high ground (National Research 

Council, 2011). Evaluation of the vulnerability and preparedness 

of the coastal communities would also help determine the overall 

readiness and resilience of the California coast to tsunamis.

Conclusions

Tsunamis are credible threats to California coastal 

communities. Understanding how communities are specifically 

vulnerable to tsunamis will help local and State officials 

develop and target realistic preparedness and education efforts. 

The California maximum tsunami-inundation zone, on the 

basis of a suite of sources, contains 267,347 residents, 168,565 

employees, and numerous public venues, dependent-population 

facilities, community-support businesses, and high-volume 

beaches. Certain communities have high percentages of groups 

that may need targeted outreach and preparedness training, 

such as renters, the very young and very old, institutionalized 

and noninstitutionalized group quarters (for example, military 

housing, correctional facilities, and university dormitories), 

and individuals where English may be a second language. 

Sustained education is also important at several high-occupancy 

public venues in the tsunami-inundation zone (for example, city 

and county beaches, State or national parks, and amusement 

parks), where daily visitor attendance at one county’s beaches 

on a single day may be four times greater than the number of 

residents in the tsunami-inundation zone for the entire State.

Communities vary in the types of people that are in 

tsunami-prone areas. Although the communities of Santa 

Cruz and Pacifica have highly mixed populations, the exposed 

populations in other communities are dominated by certain 

subgroups, such as residents in Oxnard, employees in Oakland, 

tourists at public venues in Avalon, and beach visitors in Los 

Angeles County and San Diego. Education efforts will vary 

for these different audiences. Sustained education for residents 

could be implemented through existing social networks (for 

example, neighborhood groups, church groups, and parentteacher associations) and could capitalize on residents’ 

familiarity with their surroundings. Sustained education for 

employees cannot assume this familiarity with surroundings 

or with tsunami hazards. For industry-related businesses, 

education efforts may address the potential for hazardous 

materials or heavy equipment to hinder an individual’s ability 

to evacuate. For tourism-related businesses, employees would 

ideally be trained in crowd control. Although tourists at public 

venues and beaches likely make up the highest number of 

people in the tsunami-inundation zone, they are also likely to 

be the hardest to reach. Newer social-media technologies may 

be needed to reach tourist populations that are not exposed to 

community-outreach efforts.

Community exposure to tsunamis in California varies 

considerably among 94 communities and 20 counties—some 

may experience great losses that nevertheless affect a small 

part of their community, and others may experience relatively 

small losses that devastate them. The cities of Alameda, 

Oakland, and Long Beach have the highest amounts of 

people and related businesses in the tsunami-inundation zone, 

whereas the cities of Belvedere, Alameda, and Crescent City 

have the highest percentages of people and related businesses 

in the tsunami-inundation zone. Communities with more 

people in the tsunami-inundation zone may end up having 

higher losses from a tsunami, but communities with high 

percentages of their people in the tsunami-inundation zone 

may experience greater relative impacts and social disruption 

and have fewer internal resources available during recovery. 

A difficult policy question for managers is how to allocate 

limited risk-reduction resources––to the communities with 

potentially high losses, to the communities that may be 

incapable of adapting to the loss of significant percentages of 

their community, or to a specific demographic or economic 

sector. The cities of Alameda, Belvedere, and Crescent City 

(fig. 28) have the highest community exposure to tsunami 

hazards, on the basis of composite indices that compare the 

relative number and percentage of people and businesses in 

the tsunami-inundation zone.

This report was developed to support collaboration 

between the California Emergency Management Agency, 

California Geological Survey, and the U.S. Geological Survey 

that focuses on improving our understanding of community 

vulnerability to tsunamis. Information presented in this report 

will hopefully support emergency, land-use, and resource 

managers, as well as the coastal communities, in their efforts 

to identify where additional preparedness, mitigation, recovery 

planning, and outreach activities may be needed to manage risks 

associated with California tsunamis. 

Acknowledgments

This study was supported by the USGS Geographic 

Analysis and Monitoring (GAM) Program and the USGS 

National Geospatial Program (NGP). We specifically thank 

Julia Fields of the NGP and Jonathan Smith of GAM for 

their support of this project. We also thank Lucy Jones for 

creating a collaborative environment with State agencies 

through the USGS Science Application for Risk Reduction 

(SAFRR) project that made this study possible. Finally, we 

thank Kevin Miller of the California Emergency Management 

Agency, Rick Wilson of the California Geological Survey, 

Matt Schmidtlein of Sacramento State University, and Susan 

Benjamin, Ron Kirby, and Mara Tongue of the USGS for their 

insightful reviews of the manuscript.
44 Community Exposure to Tsunami Hazards in California

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Appendixes 47

Appendixes
48 Community Exposure to Tsunami Hazards in California

Appendix 1. Table of predicted tsunami run-up heights and primary sources for selected locations on the California coast (from Wilson 

and others, 2008). 

[Sources for maximum run-up refer to past events (for example, “1964 Alaska”) or modeled scenarios (for example, “Aleutians 3”). Additional information on 

the various sources can be found in Wilson and others (2008). n.a., not applicable]

Location County

Maximum 

onshore

runup 

elevation 

(feet)

Distant source Local source

High

incoming 

wave 

elevation 

(feet)

Source for 

maximum 

run-up

High 

incoming 

wave 

elevation 

(feet)

Source for maximum run-up

Crescent City Del Norte 44.61 17.38 Aleutians 3 29.52 Cascadia Subduction Zone (entire length)

Humboldt Bay (Inside) Humboldt 17.06 10.17 1964 Alaska 17.06 Cascadia Subduction Zone (entire length)

Arena Cove Mendocino 21.98 12.14 Aleutians 3 n.a. n.a.

Bodega Bay Sonoma 20.99 15.09 Aleutians 3 n.a. n.a.

Point Reyes Marin 22.63 19.02 Aleutians 3 9.84 Point Reyes thrust fault

Bolinas/Stinson Beach Marin 25.26 19.35 Aleutians 3 7.54 Point Reyes thrust fault

San Francisco San Francisco 18.70 13.45 Aleutians 3 3.94 Point Reyes thrust fault

Sausalito Marin 12.14 10.17 Aleutians 3 5.90 Point Reyes thrust fault

Mare Island Solano 5.25 3.94 Aleutians 3 2.62 Point Reyes thrust fault

Richmond Contra Costa 11.48 9.51 Aleutians 3 3.94 Point Reyes thrust fault

Alameda Alameda 16.73 16.07 Aleutians 3 4.26 Point Reyes thrust fault

Redwood City San Mateo 6.89 5.25 Aleutians 3 3.94 Point Reyes thrust fault

Pacifica San Mateo 24.27 18.37 Aleutians 3 6.56 Point Reyes thrust fault

Half Moon Bay San Mateo 32.14 26.57 Aleutians 3 9.51 Point Reyes thrust fault

Santa Cruz Santa Cruz 29.52 19.35 Aleutians 3 18.70 Monterey Canyon Landslide

Monterey Monterey 18.37 15.74 Aleutians 3 15.09 Monterey Canyon Landslide

Cayucos San Luis Obispo 32.47 23.94 Aleutians 3 3.61 1927 Point Arguello earthquake

Port San Luis San Luis Obispo 38.70 37.06 Aleutians 3 2.95 1927 Point Arguello earthquake

Pismo Beach San Luis Obispo 31.49 26.57 Aleutians 3 n.a. n.a.

Point Arguello Santa Barbara 9.18 7.22 Aleutians 3 3.94 1927 Point Arguello earthquake

Santa Barbara Santa Barbara 31.16 13.12 Aleutians 3 25.91 Goleta Landslide no.2

Ventura Ventura 12.46 10.17 Aleutians 3 7.22 Channel Islands thrust fault

Oxnard Ventura 10.17 8.53 Aleutians 3 9.51 Goleta Landslide no.2

Malibu Los Angeles 8.20 4.92 Aleutians 3 7.54 Anacapa-Dume Fault

Santa Monica Los Angeles 11.81 8.86 Aleutians 3 5.90 Palos Verdes slide no.1

LA Harbor Los Angeles 16.40 13.12 Aleutians 3 7.54 Palos Verdes slide no.2

Huntington Beach Orange 16.40 8.20 Aleutians 3 15.74 Palos Verdes slide no.2

Newport Beach Orange 15.74 4.59 Aleutians 3 13.45 Catalina Fault

Dana Point Orange 20.01 6.89 Aleutians 3 13.12 San Mateo thrust fault

San Clemente Orange 17.06 6.23 Aleutians 3 16.07 San Mateo thrust fault

Oceanside San Diego 15.74 8.86 Aleutians 3 12.79 Carlsbad thrust fault

Del Mar San Diego 19.02 7.87 Aleutians 3 17.06 Carlsbad thrust fault

La Jolla San Diego 15.42 7.54 Aleutians 3 9.18 Carlsbad thrust fault

San Diego Bay San Diego 6.56 4.26 Aleutians 3 2.95 Coronado Canyon slide

Coronado San Diego 17.06 7.54 Aleutians 3 17.06 Carlsbad thrust fault

Imperial Beach San Diego 17.38 6.89 Aleutians 3 15.74 Coronado Canyon slide
Appendixes 49

County Park name Attendance Park 

level

Del Norte

Pelican State Beach 12,028 State

Tolowa Dunes State Park 26,496 State

Redwood National Park 407,128 National

Del Norte Coast Redwoods State Park 43,330 State

Prairie Creek Redwoods State Park 137,098 State

Humboldt

Humboldt Lagoons State Park 150,961 State

Harry A. Merlo State Recreational Area 54,263 State

Patrick's Point State Park 118,064 State

Trinidad State Beach 54,216 State

Little River State Beach 13,080 State

Fort Humboldt State Historic Park 36,911 State

Mendocino

Sinkyone Wilderness State Park 7,969 State

MacKerricher State Park 709,607 State

Jug Handle State Natural Reserve 101,342 State

Caspar Headlands State Beach 24,465 State

Caspar Headlands State Natural Reserve 30,909 State

Point Cabrillo Light Station State 

Historic Park 51,606 State

Russian Gulch State Park 156,780 State

Mendocino Headlands State Park 873,164 State

Van Damme State Park 210,454 State

Navarro River Redwoods State Park 61,442 State

Manchester State Park 55,193 State

Schooner Gulch State Beach 39,409 State

Marin

Sonoma Coast State Park 3,068,517 State

Tomales Bay State Park 86,277 State

Point Reyes National Seashore 2,116,704 National

Mount Tamalpais State Park 609,472 State

Angel Island State Park 136,513 State

China Camp State Park 95,654 State

Benecia State Recreational Area 180,896 State

San

Francisco

Golden Gate National Recreation Area 14,823,791 National

Fort Point National Historic Site 1,393,467 National

Candlestick Point State Recreational 

Area 149,806 State

San Mateo

Gray Whale Cove State Beach 31,898 State

Montara State Beach 66,817 State

Half Moon Bay State Beach 896,588 State

San Gregorio State Beach 491,334 State

Pomponio State Beach 236,634 State

Pescadero State Beach 373,135 State

Bean Hollow State Beach 192,994 State

Santa Cruz

Ano Nuevo State Park 201,741 State

Big Basin Redwoods State Park 635,822 State

Wilder Ranch State Park 104,070 State

Natural Bridges State Beach 248,500 State

Twin Lakes State Beach 524,801 State

New Brighton State Beach 375,062 State

Seacliff State Beach 612,299 State

Manresa State Beach 190,059 State

Sunset State Beach 197,404 State

City of Santa Cruz 651,929 City 

City of Capitola 201,700 City 

Monterey

Zmudowski State Beach 34,764 State

Moss Landing State Beach 212,560 State

Salinas River State Beach 244,828 State

Marina State Beach 473,118 State

Monterey State Beach 443,641 State

Monterey State Historic Park 171,161 State

Asilomar State Beach 622,790 State

Carmel River State Beach 23,590 State

Point Lobos State Natual Reserve 333,431 State

County Park name Attendance Park 

level

San Luis 

Obispo

Hearst San Simeon State Park 260,700 State

Harmony Headlands State Park 5,407 State

Estero Bluffs State Park 23,492 State

Morro Strand State Beach 232,287 State

Morro Bay State Park 1,726,466 State

Montana De Oro State Park 760,061 State

Pismo State Beach 482,427 State

Oceano Dunes SVRA 1,614,189 State

Point Sal State Beach 2,656 State

City of Morro Bay 97,828 City 

Port San Luis Harbor District 86,120 County

City of Pismo Beach 342,340 City 

Santa

Barbara

Gaviota State Park 75,575 State

Refugio State Beach 155,092 State

El Capitan State Beach 203,850 State

Carpinteria State Beach 893,300 State

City of Santa Barbara 289,613 City 

County of Santa Barbara 2,721,462 County

Ventura

Emma Wood State Beach 137,383 State

San Buenaventura State Beach 106,473 State

Channel Islands National Park 310,147 National

McGrath State Beach 160,543 State

City of Port Hueneme 400,000 City 

County of Ventura 93,680 County

Los

Angeles

Point Mugu State Park 388,440 State

Santa Monica Mountains National 

Recreation Area 538,701 National

Leo Carrillo State Park 498,549 State

Robert H. Meyer Memorial State Beach 258,169 State

Malibu Creek State Park 463,916 State

Malibu Lagoon State Beach 152,815 State

City of Los Angeles 476,415 City 

City of Long Beach 6,600,000 City 

County of Los Angeles, Parks and 

Recreation Department 1,624,065 County

County of Los Angeles, Fire Department 57,070,425 County

Orange

Bolsa Chica State Beach 2,373,052 State

Huntington State Beach 2,182,769 State

Crystal Cove State Park 1,040,789 State

Doheny State Beach 1,695,003 State

San Clemente State Beach 445,384 State

San Onofre State Beach 1,763,340 State

City of Seal Beach 1,975,000 City 

City of Huntington Beach 7,986,932 City 

City of Newport Beach 7,102,152 City 

City of Laguna Beach 3,912,483 City 

City of San Clemente 2,388,800 City

County of Orange 6,684,000 County

San Diego

Carlsbad State Beach 1,387,963 State

South Carlsbad State Beach 1,228,796 State

San Elijo State Beach 860,706 State

Cardiff State Beach 1,538,338 State

Torrey Pines State Natural Reserve 519,562 State

Torrey Pines State Beach 1,712,400 State

Silver Strand State Beach 481,357 State

Border Field State Park 51,209 State

Camp Pendleton 974,209 City 

City of Oceanside 3,835,213 City

City of Encinitas 3,440,422 City

City of Solana Beach 207,300 City

City of Del Mar 1,763,255 City

City of San Diego 23,969,337 City

City of Coronado 2,965,000 City

City of Imperial Beach 2,592,600 City

Appendix 2. Attendance for various city and county, State, and national beaches and parks.

[City and county data are from 2010 (U.S. Lifesaving Association, 2012). Data representing State parks and National parks are from the 2009–2010 fiscal year 

(California State Parks, 2010; National Park Service, 2011)]

Produced in the Menlo Park Publishing Service Center, California

Manuscript approved for publication, September 30, 2012

Edited by James H. Hendley II

Layout and design by Jeanne S. DiLeo
Wood and others—Community Exposure to Tsunami Hazards in California—Scientific Investigations Report 2012–5222