Progressive estimation of hypocentres and three dimensional crustal model

Abstract

The arrival times of a set of earthquakes at a seismic station network<br />contain information both on the hypocentres of earthquakes as well as on<br />the physical parameters of the area crossed by seismic ray paths. This<br />paper discusses an evaluation that renders possible the contemporary<br />reckoning of both the hypocentres and the model by means of a set-up ot<br />two computer program types which have separate characteristics but are<br />both capable of reckoning the arrival times at the stations with three-dimensional<br />variable speed models and the employment of a routine edited<br />by the CERN COMPUTER CENTRE so as to minimize residuals.<br />To do this, the work is carried out following a sequece of approximations:<br />on the basis of an initial model the hypocentres are worked out,<br />and on the basis of the latter a more detailed model than the former is<br />subsequently worked out; this process is repeated until a satisfactory solution<br />is obtained.<br />In this paper, in order to determine the efficiency of the method employed,<br />a theoretical simulation is used which gives encouraging results.