U.S. Department of the Interior

U.S. Geological Survey

Fact Sheet 2007–3037

May 2007

Increasing the Resilience to Natural Hazards in Southern 

California

Printed on recycled paper

Southern California is at great risk for extreme catastrophic 

losses owing to numerous natural hazards, such as earthquakes, 

wildfires, floods, tsunamis, landslides and coastal changes, that 

occur in this area (fig. 1). Expected losses from these hazards 

are estimated to exceed $3 billion per year in the eight counties 

of southern California. 

In southern California

Natural hazards have devastating consequences, including 

loss of life and injury, replacement costs of buildings and 

infrastructure, loss of function of critical facilities, service 

and infrastructure outages, business interruption, loss of jobs, 

and a decrease in the quality of life.

Multiple natural hazards are commonplace and often overlap 

to create secondary hazards. For example, earthquakes can 

produce landslides and severe fires and heavy storms can 

produce debris flows. 

•

•

Figure 1.  Geographical extent and overlap of natural hazards in southern California. 

Every year since 2000, when the population of the eight 

counties of southern California was nearly 19.7 million 

people, an estimated 276,000 more people become at risk 

from primary and secondary natural hazards. 

Decision makers require different types of information at a 

wide range of spatial and temporal scales. The decision-making environment is dynamic and therefore decision makers 

need to be able to access the most recent information derived 

from scientific investigations that account for human and 

natural forces of change.

Effective risk-reduction options depend on resources that 

are subject to budget constraints and on personal or organizational preferences for acceptable levels of risk; therefore, 

models and simulation studies are useful for quantifying 

options.

•

•

•

KERN

ORANGE

VENTURA

SAN

DIEGO

RIVERSIDE

IMPERIAL

SANTA

BARBARA

SAN BERNARDINO

SAN LUIS OBISPO

KERN

ORANGE

VENTURA

SAN

DIEGO

RIVERSIDE

IMPERIAL

LOS

ANGELES

SANTA

BARBARA

SAN BERNARDINO

SAN LUIS OBISPO

0 50 Miles

0 50 Kilometers

EXPLANATION

Earthquake-damaged areas since 1850

 (Modified Mercalli Intensity Scale VII)

Wildfire areas since 1910—1,000 or more acres

Earthquake and wildfire areas overlapping

Historic flood inundation area

Urbanized areas—500 or more persons per 

 square mile

Tsunami zone—shown schematically

Landslide zone - areas of steep terrain

Rivers subject to flooding

CALIFORNIA

Study

area

120° 118° 116°

33°

32°

35°

34°

Santa

Barbara

San

Diego

U.S.

MEXICO

Palm

Riverside Springs

Los

Angeles

Lancaster

The study area of the project will span the 

urban areas of southern California, including 

the Los Angeles and San Diego metropolitan 

areas, and will extend north to Santa Barbara, east to Lancaster and Palm Springs, and 

south to the Mexican border.
Natural-hazard information is useful to community 

decision makers in preparing risk-reduction strategies. To 

provide the best scientific information on natural hazards, the 

USGS will carry out research to increase the understanding of 

the framework of hazard possibilities, vulnerable environments, 

community response, and associated risk-reduction options. The 

vulnerable environment is in part created by humans, but natural 

elements such as the soils, geology, hydrology and ecology 

also make an environment vulnerable. The goal of the USGS 

activities is to provide an understanding of the relationships 

between human actions and environmental vulnerabilities to 

aid in making informed decisions about possible risk-reduction 

activities.

To accomplish the objectives of the Multi-Hazard 

Demonstration Project, the USGS will

Ensure that research will be useful to the communities of southern 

California.

Conduct the best possible multidisciplinary scientific research.

Work in partnership with the region’s communities to support them in 

using the research results.

•

•

•

Photograph by M.J. Rymer, U.S. Geological Survey

Natural gas pipeline broken as a result of the 1994 Northridge 

earthquake in southern California.

Contacts:

Dr. Lucile Jones

U.S. Geological Survey

Multi-Hazards Demonstration Project,

 Chief Scientist

525 South Wilson Avenue

Pasadena, CA 91106 

Dale A. Cox

U.S. Geological Survey

Multi-Hazards Demonstration Project,

 Project Manager

6000 J Street, Modoc Hall

Sacramento, CA 95819

2003 Cedar Fire, San Diego County, southern California. About 

280,000-acres burned.

The Multi-Hazards Demonstration Project (MHDP), 

initiated by the U.S. Geological Survey in 2007, brings together 

multiple disciplines and partners to help communities in 

southern California reduce death and destruction from natural 

hazards. To help increase the resilience of communities to future 

natural hazards, the project combines the knowledge of geology, 

water resources, geography, and biology with sound economic, 

engineering, social science and geospatial information 

capabilities to

Create a focal point to improve communication among scientists and disaster managers and community planners.

Plan USGS science projects with community partners. Interaction with community partners will aid the USGS in understanding community needs, improve emergency-management 

decisions, and guide future USGS research. 

Initiate or expand real-time hazard monitoring and warning 

systems.

Provide new and easy-to-access hazards data, information, 

assessments, and models for use by community decision 

makers and researchers.

Develop and improve new research products, tools, risk maps, 

and assessments. Combine geologic, hydrologic, geographic, 

and biologic hazard products with economic, engineering and 

social science research to improve emergency-management 

decisions.

Use the best of what is developed for the MHDP for southern 

California to build a robust Urban Hazards program for the 

Nation.

•

•

•

•

•

•

Landslide at Laguna Beach, California, June 2005. The landslide 

occurred after record heavy rainfall in southern California in the 

preceding months. It occurred next to the 1978 Bluebird Canyon 

landslide.

The San Fernando earthquake of 1971 collapsed freeway 

overpasses in southern California.

Photograph by Robert E. Wallace

Photograph by Rudolph R Contreras, U.S. Geological Survey

Photograph by Jim Bowers, U.S. Geological Survey