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Discrimination between earthquakes and chemical explosions in Eastern Russia using amplitude ratios obtained from analog records

Posted on:2007-10-15Degree:M.SType:Thesis
University:Michigan State UniversityCandidate:Linkimer, LepoltFull Text:PDF
GTID:2440390005472167Subject:Geophysics
Abstract/Summary:
Amplitudes information from 237 earthquakes (1.5Amplitudes information from 237 earthquakes (1.5<mb<4.9, 10<Delta<916 km) and 247 explosions (1.4<mb<3.9, 6<Delta<752 km) recorded by short period analog seismometers in Eastern Russia were used to calculate 1164 amplitude phase ratios of five different types: Pg(h)/Sg(h), Pg(z)/Sg(z), Pg(h)/Sg(z), Pg(z)/Sg(h), and full vector. These amplitude ratios were analyzed in two regions of the Yakutia and Magadan regions of Eastern Russia as earthquake-explosion discriminants in four different ways: the raw phase ratio, the distance-corrected phase (DCP) ratio, the network-averaged phase (NAP) ratio, and the network-averaged distance-corrected phase (NADCP) ratio.; There is a tendency of chemical explosions to have higher values than earthquakes for all types of amplitude ratios studied. The best earthquake-explosion discriminants found for both regions were Pg(h)/Sg(h), Pg(z)/Sg(h), and full vector NAP and NADCP ratios. These discriminants allow for the classification of 86-92% of the ratios as being either earthquakes or explosions. Distinct separations were also found analyzing stations separately.
Keywords/Search Tags:Earthquakes, Explosions, Ratios, Amplitude, Eastern russia
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