ABAG Shaken
Awake! Report
Northern Calaveras 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 Northern Calaveras Earthquake
This scenario earthquake is for a magnitude 7.1 earthquake on the northern segment of the Calaveras fault, extending from Danville in central Contra Costa County south to Calaveras Reservoir in northern Santa Clara County.
The overall damage estimate of 15,428 dwelling units for an event on the northern portion of the Calaveras fault is shared mainly between Alameda, Contra Costa, San Francisco, and Santa Clara counties. The impacts would be most severely felt in Alameda County, as 40% of the uninhabitable dwelling units would be located within this county. As with the southern portion of the Hayward fault which impacts a similar latitude of Alameda County, post-1939 wood frame housing three stories and under would account for the highest percentage of the total damaged units. This type of construction is also the most commonly impacted in Contra Costa County.
An event along the northern portion of the Calaveras fault would have the most significant housing impacts in Alameda County. Over 41% of the total shelter population would come from Alameda County alone. The expected peak shelter population is over 81% greater in Alameda County than in Contra Costa County and over two times greater than in Santa Clara County. This relationship is because the projected uninhabitable dwelling units in Alameda County are greater and also because of demographic factors. While in Alameda County the ratio between uninhabitable dwelling units and peak shelter population is 1.52, in Santa Clara County this ratio is 1.33 -- a greater number of uninhabitable dwelling units per each shelter-seeking individual is projected in Santa Clara County than in Alameda County.
In addition, the pattern described in the previous scenarios in which in the older and denser counties appear to generate shelter populations with less severe damage to their buildings is repeated here. This pattern is particularly evident when comparing San Francisco and Santa Clara counties' yellow and red-tagged peak shelter populations -- in San Francisco 79% would come from yellow-tagged buildings while in Santa Clara County the equivalent number is only 43%.
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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.
