Seismic Source and Structure in Iran from Joint Seismic Program Array Data

摘要

Our Final Report consists of the paper titled Discrimination of Earthquakes andExplosions in Southern Russia using Regional High-Frequency Three-Component Data from the IRIS/JSP Caucasus Network. In this paper, we analyzed high-frequency regional records from small earthquakes (magnitude <4.5), and comparable magnitude chemical explosions to find a reliable seismic discriminant in southern Russia near Kislovodsk. The digital, three-component seismograms recorded during 1992 by the Caucasus Network operated by Lamont-Doherty Earth Observatory since 1991 in the distance ranges 15 to 233 km are used. We find that the PgILg spectral ratios of rotated, three-component regional records improve the discrimination power of the spectral ratio method over the vertical-component Pg/Lg ratios by about 4%. But we find that an even better discriminant is the Pg/Lg spectral ratio of the three-component regional records corrected for the free surface effect. In the frequency band 8-18 Hz, the free surface corrected three-component Pg/Lg spectral ratio provides discrimination power with a total misclassification probability of only 2.6%. Free surface corrected and network averaged Pg/Lg spectral ratios provide transportability of the spectral ratio method to various regions worldwide.