[Sca-cooks] Chilean Earthquake (OT)
Daniel & Elizabeth Phelps
dephelps at embarqmail.com
Sat Feb 27 08:18:19 PST 2010
I wonder how Suey is doing down there? It seems to have been as large a
quake or even a little stronger than the one that hit Haiti. The news report
I read sounded dire.
Please note that I'm not a seismologist but a coastal geologist who dabbles
in shallow marine geophysics. That being said quake magnitudes are
logarithmic, http://en.wikipedia.org/wiki/Richter_magnitude_scale . The
main Haitian quake was IIRC 7.0. The Chilean quake is reported to have
been 8.8. It is an under statement to say that the Chilean quake was more
powerful. The question is what was the apparent strength of the quake at
various cities at distance from the epicenter. Such can be rather quirky.
Second question, what are the strengths of the after shocks. Typically the
first round of after shocks are roughly a magnitude less then the first
quake, say 7.8 +/- .5 or so. Thus the first after shocks are likely to be
greater than the Haitian quake. The second round of subsequent after shocks
will likely to be more or less in the range of the Haitian quake, say 6.8
+/- .5. The third round of after shocks should ring in around 5.8 +/- .5.
See the pattern? This sequence does not take into account the possibility
of additional quakes in the strength of the original, triggered by the
original, occurring. They are in for a rather rough ride.
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