Expected Housing Losses in an Earthquake

In 2003, ABAG updated the housing loss estimates in the report Preventing the Nightmare to be consistent with the scenarios used in the USGS Working Group 2002 probability models. The housing loss model is based on building damage data from past California earthquakes. For more information on the assumptions used in this model, see sources.

How large will housing losses be?

The Loma Prieta earthquake caused a total of over 16,000 uninhabitable units throughout the Monterey and San Francisco Bay Areas. Thirteen of the 18 potential Bay Area earthquake scenarios have a far larger impact than the Loma Prieta Earthquake. Many Bay Area faults can generate earthquakes and every Bay Area county is significantly affected by at least two. Several of the larger earthquakes will impact several counties severely.

Source: The following estimates of uninhabitable units for Bay Area counties in selected earthquake scenarios is summarized from the ABAG 2003 reportĀ Preventing the Nightmare. Download the full table.

Earthquake Scenario Alameda Contra Costa Marin Napa San Francisco San Mateo Santa Clara Solano Sonoma Total
Loma Prieta – actual data 3,284 0 2 0 9,202 76 408 0 0 12,972
1906 repeat – Entire Bay Area San Andreas 16,048 1,173 3,495 20 82,354 24,472 29,593 185 2,530 159,870
Entire Hayward 88,265 10,102 2,125 36 37,670 1,616 14,273 1,046 559 155,692

What building types will be affected?

Source: The following estimates of uninhabitable dwelling units by building type is summarized from Shaken Awake!, ABAG 1996. Find more information about impacts of past California earthquakes on buildings

Construction Type Data for Earthquake Scenarios Mobile Homes URM Wood
Multi-Family
Wood
1-3 Stories <1940 Single Family
Wood
1-3 Stories >1939 Single Family
Loma Prieta – actual data 101 1,936 2,901 301 75
1906 repeat – Entire Bay Area San Andreas 9,581 11,543 110,113 6,909 1,699
Entire Hayward 11,147 12,894 103,132 11,065 2,175

How many people will need shelter?

Source: Preventing the Nightmare, ABAG 1999

Graph of shelter populations over time from Northridge, Kobe and future Hayward fault scenario

What Can I Do to Prevent Housing Losses?

Residents and building owners
Local governments

Sources

Last updated: 07.24.2013