ABAG Shaken Awake! Report
Peninsula San Andreas Earthquake

from the 1996 report (NOT updated with 2003 data)
Regional Map of Ground Shaking Intensity from the Peninsula San Andreas Earthquake
Chart Showing Bay Area Housing Impacts from the Peninsula San Andreas Earthquake
Map Showing Peak Shelter Population from the Peninsula San Andreas Earthquake

This scenario earthquake is for a magnitude 7.1 earthquake on the Peninsula segment of the San Andreas fault.

An earthquake along the Peninsula segment of the San Andreas fault would cause a predicted housing loss of over 45,000 dwelling units. Of these uninhabitable units, 42% are predicted to be within San Francisco. Most of the rest of the total forecasted uninhabitable dwelling units are predicted to be in San Mateo (29%), Santa Clara (20%) and Alameda (7%) counties.

It is important to note that these numbers are higher in San Francisco than in the County of San Mateo, which is geographically closer to the fault line. Damage in San Francisco County is higher than that in San Mateo County by 46% (in calculating the percentages by which one county exceeds another, the higher number is divided by the smaller and 100% is deducted). In San Francisco, almost 6% of the total housing stock is made uninhabitable versus just over 5% in San Mateo County (see page 67 for existing total dwelling units by county). San Francisco's denser, older and more vulnerable housing types play a significant role in determining this damage pattern.

San Francisco County possesses the highest numbers of displaced and shelter populations. The high percentage of the total peak shelter population (45%) reflects the large percentage of uninhabitable units there (42%). However, because there are fewer number of individuals per dwelling unit in San Francisco County, its displaced population represents only 40% of the total. In addition to the impact of uninhabitable units, demographic factors such as income and household type make inner city areas have the largest shelter needs, offsetting the effects of smaller household size in these areas.

The housing impacts of this earthquake are higher in San Francisco than in San Mateo County where the fault source of this earthquake is located. This discrepancy points to the role of housing type and demographic factors, particularly household income, in predicting peak shelter population.


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ABAG, the Association of Bay Area Governments, is the regional planning and services agency for the nine-county San Francisco Bay Area.

This page was last updated 10/20/03 by jbp.