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INTRODUCTION

In recent years, numerous efforts have been made to improve the accuracy of regional event location from single station data by using travel time and azimuth information Magotra et al. (1987); Ruud et al. (1988); Thurber et al. (1989). Ruud et al. 1988, and Thurber et al. 1989 claimed that not only the epicenter but also the source depth can be constrained accurately with this information. Furthermore, Langston 1987, and Dreger and Helmberger 1991 showed that additional waveform modeling can increase the precision of the depth estimates and yield information on focal mechanism. The purpose of my study is to explore the utility of new IRIS data recorded at Garm, Tadjikistan, for locating regional earthquakes and determining source parameters by using travel times, azimuth data and detailed waveform analysis. Three intermediate depth earthquakes from the Hindu Kush seismic zone are used for this purpose. Because relatively little is known of the wave propagation in this region from past geophysical studies, it is essential to investigate the structure effect. This is attempted by performing a receiver function study of four teleseismic events. P, S, SsPmp phases and azimuth data are then used to determine possible depths and distances of the regional events. Travel time curves and synthetic seismograms generated by a wavenumber integration method put constraints on the source parameter estimates. Fault plane solutions are obtained by a grid search comparing relative amplitudes in the real data with those in the synthetic Green's functions.


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Next: SOURCE PARAMETER DETERMINATION Up: Ecker: Source parameters Previous: Ecker: Source parameters
Stanford Exploration Project
11/17/1997