MODELING FAULT-ZONE GUIDED-WAVES OF MICROEARTHQUAKES IN A GEOTHERMAL RESERVOIR

Fault-zone guided waves have been identified in microearthquake seismo grams recorded at the Coso Geothermal Field, California. The observed guided waves have particle motions and propagation group velocities si milar to Rayleigh wave modes, A numerical method has been employed to simulate the guided-wave propagation through the fault zone, By compar ing observed and synthetic waveforms the fault-zone width and its P- a nd S-wave velocity structure have been estimated, It is suggested here that the identification and modeling of such guided waves is an effec tive tool to locate fracture-induced, low-velocity fault-zone structur es in geothermal fields.