Separated determination of the velocity structure and earthquake hypocenter parameters on the basis of the differentiated approach

Abstract

The problem of seismic tomography, in its linearized statement, is characterized by models consisting of many parameters for velocity structures and hypocenters. The standard approach solves this problem by simultaneously finding both seismic parameters. In the present communication, we present evidence that the velocity structure can be determined at fixed values of the earthquake hypocenter parameters. Instead of the standard approach, we use differential one, which allows us to built inversion solutions stable in relation to significant noise, including errors in the hypocenter parameters as well. We conclude that the greater the number of hypocenters involved in inversion, the better the tomography result. This conclusion is proved by testing the Tjornes fault zone in the northeast of Iceland.