Journal of Natural Disaster Science
Journal of Natural Disaster Science, Volume 16, Number 3, 1995, pp.21f.
THE SOURCE MECHANISM OF THE HYOGOKEN-NAMBU EARTHQUAKE OF JANUARY 17, 1995
(Received 23 February, 1995 and in revised form 6 June, 1995)
Abstract
The Hyogoken-nambu earthquake occurred along active faults in southern Hyogo Prefecture at 5:46 on January 17, 1995 (JST; JST=GMT+9 h) and caused severe damage to several cities, especially Kobe. We determined the source mechanism and size (seismic moment and magnitude) of the earthquake from analyses of broad-band and strong-motion seismograph data. The source mechanism obtained from a long-period CMT inversion is (strike, dip, slip)=(233 degr., 83 degr., 169 degr.) with a small CLVD component (l.5%), Mo=3.0 x 10^19 Nm, Mw=6.9. We compared synthetic strong-motion seismograms computed by application of the reflectivity method to the source mechanism from the long-period CMT inversion with the observed strong-motion seismograms at near distances. We infer that the main shock consisted of 3 subevents that had a seismic moments of 1.5 x 10^19 Nm (the first subevent), 1.0 x 10^19 Nm (the second), and 0.5 x 10^19 Nm (the third).
Key words
devastating earthquake, strong motion records, CMT inversion, right-lateral strike-slip faulting