Earth Planets Space, Vol. 52 (No. 1), pp. 3-11, 2000

An imaging technique for subsurface faults using Teleseismic-Wave Records II —Improvement in the detectability of subsurface faults—

Takumi Murakoshi¹, Hiroshi Takenaka¹, and Daisuke Suetsugu²

¹Department of Earth and Planetary Sciences, Kyushu University, Fukuoka 812-8581, Japan
²IISEE, Building Research Institute, Tachihara1, Tsukuba 305-0032, Japan

(Received April 15, 1999; Revised October 13, 1999; Accepted October 13, 1999)

Abstract: We have developed an imaging algorithm for subsurface faults on the basis of the steepest descent method in our previous paper. In this paper we introduce two new techniques, the multi-event stacking and multi-master stacking, to improve detectability for subsurface faults. The multi-event stacking is a technique using data from plural earthquakes with different incident angles. The multi-master stacking is a technique using data of a single earthquake, in which the images obtained by employing different master receiver are stacked. We examined the feasibility of our approach using several trial models and synthetic data with different signal to noise ratios, different pulse durations and different incident angles in the two dimensional SHcases. In the numerical experiments, we could recover the image of the subsurface fault for all the trial models used, which indicates our method has a potential for sensing real subsurface faults.