[meteorite-list] Estimating meteorite annual fall rates
From: Matson, Robert <ROBERT.D.MATSON_at_meteoritecentral.com>
Date: Thu Apr 22 09:42:00 2004 Message-ID: <AF564D2B9D91D411B9FE00508BF1C8692C5E58_at_US-Torrance.mail.saic.com> Hi Kelly and list, Kelly wrote: > In my post to the List about calculating the frequency of meteorite > infall from the data for targets that they strike, I wrote: "The data > for U.S. automobiles is 250% of expectation, suggesting a flux of 59,825 > meteorites per year..." > That was based on four hits on U.S. automobiles per century. This > incident, if verified, would raise that to five hits per century (two of > them within four years!) or three times the number expected from an > infall of roughly 24,000 meteorites per year, which implies about 72,000 > meteorites per year actually fall. > For the decade of the 1990's, taken separately, two hits is more > than five times the chance expectation for the "official" rate of 24,000 > meteorites per year, which would translate to an equivalent rate of > 125,000 meteorites per year! I recently performed an independent analysis and calculation of global annual fall rates based on southern California meteorite finds from a number of Meteorite Recovery Foundation (MRF) study areas. This calculation involved search surface areas, visual detection range vs. search velocity, total field manhours per study area, and a variety of assumptions about surface age, deflation and weathering. Using the most pessimistic assumptions, the global annual rate computed to ~160,000 for meteorites 10 grams or larger. The actual value is probably several times higher than this. --Rob Received on Tue 16 Jan 2001 05:52:20 PM PST |
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