S/P Travel Time Ratio in Central Asia
Semiannual technical rept. 1 Oct 1973-31 Mar 1974
TELEDYNE GEOTECH GARLAND TX
Pagination or Media Count:
The SP travel time ratio for intermediate depth Hindu-Kush earthquakes is investigated, using S and P arrival times at six World Wide Standard Seismograph Network stations and 19 other close-in stations. Station mean values of the ratio range from 1.74 to 1.81, with an overall mean value of 1.78. The SP travel time ratio increases slowly with increasing distance over the distance range 4.5 to 13.0 degrees, and increases rapidly with decreasing distance for distances less than 4.5 degrees. Variation of the ratio with focal depth is weak. The standard deviation of SP origin time deviations from origin times based on locations restrained to pp depth is about 1.0 second, implying a standard deviation of SP depth error, relative to pp depth, of 10 to 12 km.