Broad-band moment tensor inversion from single station, regional surface waves for the 1990, NW-Iran earthquake sequence

Abstract

e present a method for the inversion of complete waveforms in the 5-30 mHz frequency band for moment tensor determination. The method is based on the calibration of phase and group velocity dispersion curves for Rayleigh and Love fundamental modes to account for heterogeneous lithospheric structure, and is applied to the analysis of single station records of the VSL MEDNET station for the 1990 NW Iran earthquake sequence (the events of June 20, 21 and 24). The revised seismic moment of the June 20, 1990 Iranian earthquake is Mo = 1.56 x 1027 dyne-cm, corresponding to Mw = 7.4. The method proves to be a very robust tool for the analysis of moderate and large earthquakes at regional distances, producing consistent moment tensor solutions trom single station inversions in narrow (2-4 mHz) and wide (up to 20 mHz) frequency bands across the whole band of interest.

Keywords

• seismic moment
• inversion techniques
• regional waveform analysis
• 1990 NW-Iran seismicity