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Re: Near source maps

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In a message dated 98-02-28 18:03:55 EST, Fred Turner writes:

<< Tom Long mentioned the USGS zip code web page as the place to find the 97
 Near source maps. This is not quite correct and could get some readers into
 trouble. I understand that the USGS map is purely probabilistic, whereas the
 97 UBC are hybrid probabilistic/deterministic maps. Bob Bachman, Tom Hale, or
 someone active on the Seismology Committee could give us an update on the UBC
 map printing progress.

[Bill Cain]  Another problem with these USGS maps is that they are based on a
uniform grid of points that are spaced at distances greater than the width of
the nearest near fault zone in th '97 Code.  Also, parts of more than one zone
may be in a given zipcode.  The best use of these maps is as a very gross
check on reasonableness of more site specific data.  

At the SEAONC seminar last fall on the '97 UBC, it was announced that the maps
were expected to be available later this year.

Bill Cain, SE
Albany, CA