ABAG Shaken
Awake! Report
Concord-Green Valley Earthquake
from
the 1996 report (NOT updated with 2003 data)
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ABAG Shaken
Awake! Report |
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from
the 1996 report (NOT updated with 2003 data)
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Regional Map of Ground Shaking Intensity from the Concord-Green Valley Earthquake
This scenario earthquake is for a magnitude 7.1 earthquake on the Concord-Green Valley fault in Contra Costa and Solano counties.
Unlike most of the other forecast scenarios outlined in this report in which the counties with the older housing stocks experience the most damage, during an event along the Concord-Green Valley fault, Contra Costa County would experience the most severe damage. Out of the total Bay Area damage of 23,431 uninhabitable dwelling units, 52% of these would occur in Contra Costa County.
In Contra Costa County, post-1939 single family dwellings and post-1939 under three story apartments are the two most common forms of housing. Together they account for almost 90% of the total stock for Contra Costa County. Of these two housing types, post-1939 one-to-three story multi-family dwellings account for most of the uninhabitable units in this earthquake scenario. In Contra Costa County, dwellings in this type of construction would account for 64% of the overall local housing that is uninhabitable.
Contra Costa County is expected to generate the largest numbers of both displaced populations (52% of the total) and of shelter populations (49% of the total). The majority of the shelter population in Contra Costa County (63%) would be generated by red-tagged dwelling units.
The pattern of a higher percentage of red-tagged generated shelter-seeking population seems to be followed by some of the other suburban counties, such as Napa, Solano and Sonoma counties. In each of these cases, 68%, 61%, and 73% of the total peak shelter population respectively, is generated by red-tagged units. On the other hand, in the more densely urbanized counties of Alameda and San Francisco, the majority of the shelter-seeking population is expected to come from yellow-tagged dwelling units -- 62% in Alameda County and 79% in San Francisco County. Because of demographic factors and because of their housing stock, it appears that the older and more densely populated counties are likely to generate shelter populations with less severe damage to their buildings.
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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.
