Refined hypocenters and accurate reliability estimates

Abstract

A new method of correcting station arrival times for systematic source and station effects has been developed. The method yields source-region/station time (SRST) corrections which have a simple spatial variation and which are valid, in terms of yielding accurate focal depths and relative epicenters, over large areas. The method has been applied to over 200 earthquakes ranging in depth from about 10 to 650 km in the Kurile-Kamchatka-Okhotsk region. Resulting corrections are uniformly valid throughout an area of approximately one million square kilometers. Full utilization of the SRST corrections for the 25 close-in and 149 teleseismic stations was achieved by weighting each station's contribution to the computed hypocenters. The 95 per cent limits on the depth uncertainty cover the pP depth the appropriate percentage of the time regardless of the number or geometry of the stations in the observing network. The SRTS's for the close-in stations describe their arrival-time variations over the entire are structure and thus may be used in model studies to determine the structure and the epicenter bias.