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Re: Richter Magnitudes

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For my non-structural project I need data with regard to earthquakes which did

(1) within a 100 miles width limit on either side of the San Andreas fault,
(2) were magnitudes 4.5 and higher and
(3) occurred between 1994 and today. 

Specifically the following data is required:

1. Year of the quake
2. North Latitude
3. West Longitude
4. Richter Scale Magnitude
5. Location (say, near Watsonville)

Where can I get this information ??? 

When I approached the US Geological Survey they told me that the data can be
extracted from their mammoth database where already quakes Magnitude 0.2 are
listed but .... they have no time for requests by private individuals. They
have more important things to do, they say (I am not sure why I payed income
taxes for more than 30 years). I know that not too many magnitude 4.5 or
higher earthquakes occurred during this time-period so it should be quite
simple to extract it from USGS database except ..... they even will not allow
access to the database nor provide a printout of the database so that I can do
it myself.

If anyone has a suggestion I would very much appreciate it. 


Most competent Geotechnical Engineers can give you this information on a 
site-specific (map point) basis.  Blake and others have written programs to 
reduce the extensive earthquake epicenter database (e.g. EQSEARCH).  You 
however, are requesting epicenters for a strip or zone.  You also bring up a 
good point, in that few still use "Richter Magnitude".  Most prefer Moment 
Magnitude, since this has a more logical derivation.  Most epicenter databases 
are a combination of both.  For your 100-mile strip along the San Andreas, I 
would suggest writing a small program to loop through the database, with a 
magnitude and time (>1994) trigger, and a defined range of latitude and 
longitude (probably steps).  This could take a few hours to write.  
Unfortunately, I am unaware of any earthquake epicenter maps prepared since 
1994, if you would prefer a "graphical" solution.  Sounds like interesting 
research.  What do you plan to do with this data?

I'm surprised that USGS will not sell you a data disk.  You can also purchase 
epicenter files from NOAA or Tom Blake in Ventura.  Your local (or should I say 
most California) Geotechnical Engineer(s) may also be willing to help you.

Tom Benson at Lowney Associates