Thanks Bob;

Guess Im thinking of the military
that does not share with anyone
and its like pulling teeth just to
look at those notes you took in class.


----- Original Message ----- 
From: "Bob Hancock" 
To: 
Sent: Wednesday, September 09, 2009 8:38 PM
Subject: Re: Earthquake Wave Attenuation


> Hi Geoff -
> 
> There are programs called artificial seismogram programs.  They are  
> normally run on UNIX based computers such as a MAC or in LINUX.  They  
> are use by seismologists and geophysicists in studying the earth's  
> interior.  You are correct in that they use generic earth models.   
> These models are constantly being revised and updated by seismologists  
> and geophysicists as they study the earth.  These models are openly  
> shared in the scientific community.  To learn more about them do a  
> google search for PREM EARTH MODELS.  The word PREM is an acronym for  
> Primary Reference Earth Model.
> 
> Cheers
> 
> Bob Hancock
> 
> 
> 
> On Sep 9, 2009, at 7:59 PM, Geoffrey wrote:
> 
>> It is my experience that with a SPZ located
>> in a noisy area you should be able to have
>> an MDL (minimum discernable level) for a
>> regional quake of 4.0 Ml (richter) at a
>> distance of 6 degrees great circle.
>> Unless you are in a quiet area do not
>> expect much better than this.
>> Im not sure what math you use but this magnitude
>> and distance can be translated from your own
>> location to 180 degrees. Spreading losses
>> and heat losses and reflection/refraction losses
>> relating to the velocity changes across various boundaries.
>> They (USGS) most likely have some kind of ideal math model of all this
>> which may be a closely guarded secret so like
>> you and I will never see the real thing to run in our
>> computers.
>>
>> Well probably only see the old stuff from like the 1950s.
>>
>>
>>
>>
>> ----- Original Message ----- From: "Richard Webb" > >
>> To: "PSN-L Mailing List" 
>> Sent: Wednesday, September 09, 2009 9:33 AM
>> Subject: Earthquake Wave Attenuation
>>
>>
>>> Hi,
>>> I am interested in locating a paper which describes the  
>>> relationship between earthquake detectability, magnitude and  
>>> distance.  Assumptions are a generalized earth model and  
>>> seismometers, with respect to sensitivity, available to "amateurs".  
>>> Dick
>>> -- 
>>> Richard Webb
>>> Raleigh, NC
>>> Farr and Webb Family Genealogy site:  http://Genequake.com/Genealogy
>>> Family and Seismology site:  http://Genequake.com
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> 
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