Accession Number : ADA323774

Title :   Path Calibration, Source Estimation and Regional Discrimination for the Middle East and Western Mediterranean.

Descriptive Note : Scientific rept. no. 2,

Corporate Author : WOODWARD-CLYDE FEDERAL SERVICES PASADENA CA

Personal Author(s) : Saikia, C. K. ; Thio, H. K. ; Woods, B. B. ; Song, X. ; Zhu, L.

PDF Url : ADA323774

Report Date : 01 JUL 1996

Pagination or Media Count : 216

Abstract : In our efforts to calibrate regional crustal paths and upper-mantle teleseismic effects for the Middle East and North Africa we have extended the coverage to include the Western Mediterranean and North Africa, a region of sharp lateral variations in the crustal waveguide. Such calibration is for use in regional magnitude corrections and path attenuation relations. We have established a regionalized zonation of surface wave paths at longer periods (T> 15 secs) and presently have a first-order working model for Pnl propagation across old oceanic paths. In the area previously calibrated -- centered about the Pamir-Hindu Kush region, and covered by the IMS b-stations NIL and AAK, we have analyzed the performance of our source location and characterization methods to smaller (4 > ML> 3) earthquakes using data from co-located or nearby temporary arrays. We establish from this analysis that two broadband three-component stations can provide useful location and depth estimates for small regional events with few (1 or 2), if any, teleseismic observations. A serendipitous result of this work is a depth estimator based on a signal's S-wave complexity. This technique is also complimentary to the short- period:long-period (Esp-pz:Eip-3) discriminant.

Descriptors :   *SEISMOLOGY, EARTH CRUST, SEISMIC WAVES, CALIBRATION, SEISMIC DISCRIMINATION, EARTH MODELS, NORTH AFRICA.

Subject Categories : Seismology

Distribution Statement : APPROVED FOR PUBLIC RELEASE