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Living on the Hayward (and San Andreas) Fault Line
Many of the inspection I perform are within just a few miles
of the Northern Branch of the Hayward Fault. This fault has had only very small releases of energy over the last 139 years
with the last major earthquake having occurred in 1868 (magnitude 6.8-7.0).
Even with the tiny population of the
east bay at that time, 30 were left dead and 1/3 of a million in damage occurred (in 1868 dollars). Today, the east bay is
heavily populated, heavily forested (fuel for a post quake fire) and ill-prepared for an overdue quake. This fault is fairly
regular in providing large (~7.0) quakes and is overdue by roughly a decade.
While earthquake insurance might
provide some coverage, there is no substitute for a well braced house that can survive such an earthquake. I devote a substantial
portion to every residential and commercial inspection to this subject in several ways including an evaluation of the foundation
and its capacity to hold bolts, how bracing has been done, what will likely be needed and how the occupants can best respond
to the actual event.
My top recommendation for nearly every house is the installation of an automatic seismic shut-off
valve. While houses may survive destruction of their lower framing during violent shaking, a broken gas line can lead to an
avoidable catastrophe. My aim is to target the most dangerous potential hazards and address them with the easiest and lowest
cost solutions. These valves definitely fill the bill. The web address below is a local seller of these valves and diagram
below shows how the “Little Firefigher” valve operates. This is only one type but one I endorse.
http://www.gasvalvedoctor.com/valve.htm
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