In a previous post Doug Miller says...
Well, Raymond, I live in Indiana, where we don't worry much about earthquakes,
and so my opinion on this subject may be worth exactly what you're paying for
it... but it seems obvious to me that a 40-50 year old building that's still
standing has proven that it's able to withstand whatever quakes have occurred
in that area in the last 40-50 years. And some of those have been pretty big.



Doug:

This is a misconception that many people have. It is entirely possible
that the structure has used up its "reserve" strength and will come
tumbling down in the next "Big One". There isn't a building yet
designed that can withstand every seismic event. The current
methodology uses a peak ground acceleration with a 10% probability of
exceedance in 50 years.

I just spent all of Saturday at a structural engineering seminar on the
seismic portion of the the new IBC2003. This code is the state of the
art in terms of how SE's understand seismic events, but the code is only
as good as the design team who implements it and the builder who
constructs the building according to the design.

BTW, Indiana is not immune. The SW corner of the state has some
relatively high seismic risk.

--
Bob Morrison
R L Morrison Engineering Co
Structural & Civil Engineering
Poulsbo WA