Automatic determination of source parameters of the 2007 Noto Hanto earthquake
© The Society of Geomagnetism and Earth, Planetary and Space Sciences (SGEPSS); The Seismological Society of Japan; The Volcanological Society of Japan; The Geodetic Society of Japan; The Japanese Society for Planetary Sciences. 2008
Received: 29 June 2007
Accepted: 5 December 2007
Published: 7 November 2008
Large earthquakes have been observed to be caused by the rupture of several asperities. The rapid determination of source parameters is hence of great importance for correctly determining shaking intensities or evaluating the strong motion distribution generated by a large earthquake. This study shows that we can automatically preprocess strong motion data using automatic P- and S-phase pickers, determine the focal mechanism, and identify the fault plane from two nodal planes. A real-time simulation is performed for the 2007 Noto Hanto earthquake. Using our automatic fault plane identificator, we were able to identify one of the nodal planes with a strike of 62° and a dip of 70° within a 30-s interval from the beginning of focal mechanism determination to the end of waveform inversion. Results from automatic inversions showed that the slip was confined to a shallow portion with a maximum slip of about 3 m. The total seismic moment released in 10 s was 2.0×1018 N m, which corresponds to a moment magnitude of 6.8.