Earthquake location by a sparse seismic network

Abstract

Hypocentral locations, and depths in particular, are affected by large uncertainties in situations where the available seismic network is sparse and with a small number of local stations recording Pg phases as first arrival (Pg phase is direct wave in the upper crust). In this study, we consider the variability of locations because of the errors associated with arrival time picks, analyzing how this variability, for a constant standard deviation in arrival times, depends on the azimuthal distribution of stations and the number of available Pg phases in the input dataset. Our analysis was carried out on real cases and confirmed the importance of including local stations in the earthquake location process, quantifying how the removal of an increasing number of local stations increased the dispersion of hypocenters.