2015 Volume 15 Issue 7 Pages 7_141-7_156
Using the waveform inversion results of recent eighteen crustal earthquakes (Mw5.4-6.9) in Japan, which happened after the 1995 Hyogo-ken Nanbu earthquake, we extracted the source parameters (entire rupture area (S) and asperity area (Sa)) from the inverted heterogeneous slip distributions following the criterion of Somerville et al.(1999). We recognized that the scaling relationship of entire rupture area S versus seismic moment M0 obtained in this study coincides with that of Somerville et al.(1999) for earthquakes with Mw <6.5 and does with that of Irikura and Miyake (2001) for earthquakes with Mw>6.5, respectively. The combined area of asperities over the entire rupture area (Sa/S) is about 0.16 in average for eighteen earthquakes, which is smaller than previous result (0.22) by Somerville et al.(1999). We examined the relationship between source fault length L estimated from the waveform inversion results and seismic moment M0. The scaling relationship of L versus M0 for earthquakes smaller than Mw6.5 is consistent with that of Takemura (1998), whereas those larger than Mw6.5 is consistent with the scaling relation of HERP (Headquarters for Earthquake Research Promotion). We further re-examined the source fault lengths estimated from the waveform inversion results of damaging earthquakes (Mw>6.5), which happened before the 1995 Hyogo-ken Nanbu earthquake. We find that re-examined relationship between source fault length L and seismic moment M0 for earthquakes with Mw>6.5 before the 1995 Hyogo-ken Nanbu earthquake also coincide with that of HERP.
