The geometry and temporal structure of a high frequency source: The Olyutorskii earthquake of April 20, 2006

摘要

We have determined the parameters of the high frequency radiator for the M (W) = 7.6, April 20, 2006 Olyutorskii earthquake using P-wave high frequency power signal (HFPS), as recorded at 57 distant stations. Our data processing was done, first, to correct the HFPSs by inverse filtering using the aftershock HFPS as an empirical power Green's function. In this way, we found the source HFPS for each station, separately for the frequency bands 0.7-1.7 and 1.5-2.5 Hz. These data were used to determine parameters of the radiator model as a segment with the rupture propagating to both sides of the hypocenter at constant velocity. The parameters are as follows: length 128 +/- 52 km, the strike of the longer arm of the rupture 225A degrees +/- 19A degrees SW, the distance from the epicenter to the centroid 23 +/- 9 km, and rupture velocity 2.5 +/- 0.8 km/s. The rupture was bilateral with a moderate asymmetry. The rupture duration was 35.0 +/- 1.6 s for the southwestern arm and about 23 s for the northeastern.