On Apr 15, 6:25*am, dave wrote:
On 04/14/2011 03:04 PM, bpnjensen wrote:



Being in a seismically active area is not quite the same as being on a
fault line. *Fault rupture is, at any given time, a more serious issue
to local buildings than the ensuing ground shaking - it will break
your structure in two; but if you are not on a fault line, then
shaking is your key problem if you are not in danger of a landslide,
tsunami or liquefaction. *A building can be built to withstand almost
any foreseeable level of shake.

Surface cracking is localized. It is not the actual fault opening up.
EQs occur a mile or more below the surface.

Correct, but you may want to come up to the Bay Area and see what has
happened at Point Reyes, Los Trancos and elsewhere. It may be surface
cracking, but the ground does open up, and the two sides exhibit
significant displacement in three dimensions. Whether it is the
actual fault is immaterial - it will disassemble structures. I'm sure
you guys have examples in SoCal, and there are some seriously
spectacular scarps in Nevada and down near Carrizo Plain, if I'm not
mistaken.