[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: Abstracts on impacts from 29th LPSC
Hello Peter,
Thank you for your posting. I do have a question. In your message, the
following was mentioned:
"Verification of the comprehensive test ban treaty (forbidding underground
nuclear bomb tests) includes seismic detectors that could be triggered by a
meteorite impact. 50 of these detectors, across the globe, can detect
seismic magnitudes of 3 or 4. This has already been an issue of concern;
in 1993, a seismic event of mag 3.6 in W. Australia occurred just north of
์where members of the Aum Shinrikyo terrorist cult had been trying to mine
uranium, and carrying out tests with chemical weapons.๎ The conclusion was
that the seismic event was probably an iron meteorite, creating a crater
over 100 meters in diameter [no mention of discovery of such a crater].
Ablation & deceleration in the atmosphere, frequency of iron & stony
meteorites, water surface of the earth, and other factors were considered.
It is concluded that meteorite impacts that could trigger the seismic
detectors occur on a time scale of decades. The existing seismic records
probably include meteorite impacts misidentified as earthquakes. (Chyba)"
Peter, if an iron meteorite fell causing a 3.6 shock, wouldn't it be
possible to use the recordings of three seismic stations, and triangulate
the information to find the crater?
It is also my understanding that two measures are provided by the
seismographs, the earth-surface location of the movement, and the depth of
the mechanics causing the movement. Since most earthquakes originate many
kilometers below the surface, there should be a clear, or at least
reasonable distinction between an impact seismic fingerprint and that of an
earthquake.
Any thoughts?
Martin
Follow-Ups:
References: