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Re: Building on Fault Lines

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Yes there are restrictions on building over a fault line.  Look at the Alquist Priolo Act.  Minimum distances are set from specific evaluation of the site in a geotechnical exploration.  Faults are not clean lines in the sand, and in some cases the fault line width and minimum set-back can make the site unbuildable.  Typically the sites where we have done projects the set back has been as little as the identified fault zone width plus 25 feet.  No restriction on building type, but substantial design level increases due to near-source effects.
There are many buildings over or on fault lines built prior to the current regulations.  In some cases substantial development, like a large part of downtown LA.
I do not know of any restrictions on nuclear plants or critical facilities beyond what the Alquist Priolo requirements would be, maybe the NRC or Energy Department would have additional requirements.
As you know, existing building code compliance is based on a phased compliance approach.  As long as the building is not substantially modified or under a change of occupancy upgrade is not required (there are exceptions, like the URM program). 
If the structure was to be torn down and a new one proposed, Alquist Priolo would definitely apply.  I am not so sure on an extensive retrofit if the question would be asked.  This is a really good question.
Alquist Priolo is at the State level.
----- Original Message -----
Sent: Tuesday, April 18, 2006 5:25 AM
Subject: Building on Fault Lines

What restrictions do California (and other states) have as far as building near fault zones?

I.e.  is there a minimum required distance through the nominal fault line?

Is there a restriction on the type of construction within a certain distance of the fault line?  I.e. you can't build a nuclear reactor on top of a known fault line?

When did restrictions start going into place?

When existing buildings are renovated / converted does there distance to a fault line become an issue?

What document / code are there requirements/restrictions contained in?

At what level of government (city / county / state) is this type of restriction promulgated?

Gail Kelley