Yesterday at open house in Almaden I was asked by a gentleman about earthquakes which is actually an infrequent question.  I commented to the man that the earthquake faults are disclosed in Natural Hazard Disclosure maps for all properties, but this seems to have little impact on Silicon Valley property values probably because everyone is aware that the Bay Area is “earthquake country”.  Most people know about the 1989 Loma Prieta earthquake.

Perhaps the gentleman was prescient about the 4.3 magnitude earthquake this morning 11 miles north of Morgan Hill at an “unnamed fault”.  Click>here for a link to the USGS map showing recent earthquake activity. Click>here for the Northern California Shake Map.

What is lesser know is that areas subject to liquifaction may also experience damage, not just those in a fault zones.  Much of Santa Clara County has “low to moderate” susceptibility of earthquake damage due to liquifaction.  The risk is very high in some neighborhoods that border right on the south bay.

Earthquake Fault Zone Maps (also known as the Alquist-Priolo Earthquake Fault Zone Maps) show active earthquake faults prone to surface ruptures and identify a 1,000 ft. wide zone with the fault line at the center. General maps of Bay Area faults are available online from USGS;  detail Alquist-Priolo maps are ordered from disclosure companies for every property for sale.

There are several things that should be done to minimize the damage from earthquakes such as strapping water heaters; adding anchor bolts to foundations if missing; strengthening cripple walls with plywood; strengthening pier and post foundations; replacing unreinforced masonry foundations; strengthening masonry chimneys, etc.  Click>here for general earthquake disclosure information.