NetNews Usenet Archive 1992 #27/NN_1992_27.iso/spool/sci/geo/geology/2387

Internet Message Format | 1992-11-17 | 1.6 KB

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From: [e-mail] (Richard Stead)
Newsgroups: sci.geo.geology
Subject: Re: To John Hammer
Message-ID: <[e-mail]>
Date: 16 Nov 92 19:57:52 GMT
References: <[e-mail]>
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In article <[e-mail]>, [e-mail] (William Rivas) writes:
> Thanks so much for the information you were able to gather
> for me. I am curious as to the term "Intensity", does this
> indicate a Magnitude. Intensity IV, would that indicate a
> magnitude 4 seismic disturbance.

I can help here.  Intensity is how strong the shaking is at a particular place.
It changes depending on where you are relative to the quake.  Magnitude is
the size of the quake itself.  Think of it like a light bulb.  The Magnitude
is a bit like the wattage, the intensity is just like the light intensity -
as you get farther from the bulb, the light gets less and less, until far
enough from the bulb, you can really see much at all.

Given magnitude, the location of the quake and the location of the place
you are interested in, and a description of the geology in between,
you can make very accurate estimates of expected intensity.  Given
intensity at many places, evem without knowledge of the exact location
of the quake, you can get a good estimate of the quake's magnitude.


--
Richard Stead
Center for Seismic Studies
Arlington, VA
[e-mail]