Earthquake Risk Analysis for Los Angeles County under Present and Planned Land Uses

Abstract

Local governments rarely use risk analysis, the most sophisticated level of hazard assessment, to inform their planning and development decisions. But new tools are rapidly becoming available to accomplish such analysis. In this paper we present an example of an earthquake risk analysis for Los Angeles County, using available land-use maps, a probabilistic earthquake hazard model developed by the Southern California Earthquake Center, and the Federal Emergency Management Agency's new HAZUS earthquake loss estimation software. We computed the annual expected loss owing to earthquakes and the spatial variation of this risk. The analysis shows that the annual long-term earthquake risk in Los Angeles County, as a result of direct structural and nonstructural damage, is $388 million per year. We also investigated the extent to which planned future land-use growth would affect this risk estimate. We found that planned growth of 14.2% would result in an increase in annual risk to $449.5 million, a 15.8% increase over the risk to current land uses. Because of ever increasing disaster costs, planners need to be able to evaluate the risks that their communities face, both in the present and in the future. It is particularly important for planners to be sure that they are not disproportionately planning future growth for hazardous locations. In this paper we describe some ways in which to perform such evaluations, by using tools that have only recently become available.

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References

Applied Technology Council, 1988 Rapid Visual Screening of Buildings f or Potential Seismic Hazards: A Handbook ATC-21, FEMA-154, Federal Emergency Management Agency, 500 C Street, Washington, DC 20472

Association of Bay Area Governments, 1995 On Shaky Ground Catalogue Number P98001EQK, ABAG, Joseph P Bort MetroCenter, 101 8th Street, Oakland, CA 94607, also at www.abag.ca.gov/abag/overview/pub/eqk.html

Borcherdt

R D

(Ed.), 1994 The Loma Prieta, California, Earthquake of October 17, 1989—Strong Ground Motion Professional Paper 1551-A, US Geological Survey (US Government Printing Office, Washington, DC)

Burby

R J

(Ed.), 1998 Cooperating with Nature: Confronting Natural Hazards with Land-use Planning for Sustainable Communities (Joseph Henry, Washington, DC)

Burby

R J

French

S P

Nelson

A C

, 1998, “Plans, code enforcement, and damage reduction: Evidence from the Northridge earthquake” Earthquake Spectra 14 59–74

California Division of Mines and Geology, 1997 Guidelines f or Evaluating and Mitigating Seismic Hazards in California special publication 117, California Division of Mines and Geology, www.consrv.ca.gov/dmg/pubs/sp/117/index.htm

Deyle

R E

French

S P

Olshansky

R B

Patterson

R G

, 1998, “Hazard assessment: The factual basis for planning and mitigation”, in Cooperating With Nature: Confronting Natural Hazards with Land-use Planning for Sustainable Communities Ed. Burby

R J

(Joseph Henry, Washington, DC) pp 119–166

EQE International Inc, 1997 The Northridge Earthquake of January 17, 1994: Report of Data Collection and Analysis, Part B prepared for the Governor's Office of Emergency Services of the State of California, PO Box 419047, Rancho Cordova, CA 95741-9047

French

S P

Nelson

A C

Muthukumar

Holland

M M

, 1996 The Northridge Earthquake: Land-use Planning for Hazard Mitigation City Planning Program, Georgia Institute of Technology, Atlanta, GA 30332

10.

Kircher

C A

Reitherman

R K

Whitman

R V

Arnold

, 1997, “Estimation of earthquake losses to buildings” Earthquake Spectra 13 703–720

11.

National Institute of Building Sciences, 1997 HAZUS User's Manual prepared for Federal Emergency Management Agency, 500 C Street, Washington, DC 20472

12.

Olshansky

R B

, 1997, “The role of earthquake hazard maps in loss estimation: A study of the Northridge earthquake” Earthquake Spectra 13 721–737

13.

Olshansky

R B

, 2000, “Is my house in the red zone? Local communities and seismic hazard mapping”, in Proceedings of the Sixth International Conference on Seismic Zonation Earthquake Engineering Research Institute, 499 14th Street, #320, Oakland, CA 94612–1934

14.

Olshansky

R B

, 2001, “Land use planning for seismic safety: The Los Angeles County experience, 1971–1994” Journal of the American Planning Association 67 forthcoming

15.

Olshansky

R B

Foster

H C

Cook

, 1991, “Microzonation: A planner's perspective”, in Proceedings, Fourth International Conference on Seismic Zonation, Volume III Earthquake Engineering Research Institute, 499 14th Street, #320, Oakland, CA 94612–1934, pages 195–202

16.

Real

C R

Holden

R J

, 1991, “Special study zones: A viable approach to zonation for ground shaking hazards”, in Proceedings, Fourth International Conference on Seismic Zonation, Volume III Earthquake Engineering Research Institute, 499 14th Street, #320, Oakland, CA 94612–1934, pages 181–187

17.

Spangle Associates, 1996 Using Earthquake Hazard Maps for Land Use Planning and Building Permit Administration prepared for Metro Data Resource Center, 600 NE Grand Avenue, Portland, OR 97232–2736

18.

Tinsley

J C

Fumai

T E

, 1985, “Mapping quaternary sedimentary deposits for areal variations in shaking response”, in Evaluating Earthquake Hazards in the Los Angeles Region—An Earth Science Perspective Ed. Ziony

J I

, US Geological Survey Professional Paper 1360 (US Government Printing Office, Washington, DC) pp 101–126

19.

Toppozada

T R

Bennett

J H

Borchardt

Saul

Davis

J F

, 1988 Planning Scenario for a Major Earthquake on the Newport-Inglewood Fault Zone special publication 99, California Division of Mines and Geology, Publication Sales, 801 K Street, MS 14–33 Sacramento, CA 95814–3532

20.

Whitman

F V

Anagnos

Kircher

C A

Lagorio

H J

Lawson

R S

Schneider

, 1997, “Development of a national earthquake loss estimation methodology” Earthquake Spectra 13 643–661

21.

Working Group on California Earthquake Probabilities, 1995, “Seismic hazards in Southern California: Probable earthquakes, 1994–2024” Bulletin of the Seismological Society of America 85 379–439

22.

Wyner

A J

Mann

D E

, 1986 Preparing for California's Earthquakes: Local Government and Seismic Safety Institute of Governmental Studies, University of California, Publications Office, 102 Moses Hall, Berkeley, CA 94720–2370