HR: 0830h
AN: T51D-0188    [PDF]
TI: Rupture Areas Of Large Earthquakes In Papua New Guinea In 1971 And 2000
AU: * Park, S
EM: suncheon@rcep.dpri.kyoto-u.ac.jp
AF: Disaster Prevention Research Institute, Kyoto University, Gokasho, Uji, Kyoto, 611-0011 Japan
AB: Two large earthquakes with magnitudes greater than 7.0 (Mw) occurred near New Ireland and New Britain, Papua New Guinea, on November 16-17, 2000. Both earthquakes were thrust events with shallow dip angles in the New Britain subduction zone. Also, another two large earthquakes (both Ms 7.9) occurred in the same area on July 14 and July 26 in 1971, almost 30 years before the 2000 events. Aftershock zones of the 1971 events covered large areas, including the fault zones of the 2000 events. In this study we estimate the rupture areas of the 1971 and 2000 events using teleseismic waveform inversion and investigate their inter-relationships. To understand the rupture processes of the 1971 events, waveform inversions using Pdiff waves was carried out. Paper recordings of the Pdiff waveform data at seismic stations for distance between 100 and 140 degree were scanned from microfilm and digitalized. Synthetic seismograms were calculated with theoretical Green's Functions and the best fit between observed and synthetic seismograms was obtained by a least-square method. Fault mechanisms and rupture processes were obtained by the waveform inversion. Results of the waveform inversion showed that both earthquakes were thrust events having shallow dip angles. The July 14 event has two areas with large slip and the July 26 event has a single area of large slip. Teleseismic P wave inversions were previously carried out to understand the rupture processes of the 2000 events. P-wave data from stations at distance between 30 and 90 degree were retrieved from the IRIS data center and used for waveform inversion. As the result of the waveform inversion, both events seem to have fairly simple rupture patterns with a single area of large slip. Based on the result of the waveform inversions, we will discuss the relationships between the rupture areas of the 1971 and 2000 events, and their rupture mechanisms.
DE: 7200 SEISMOLOGY
DE: 7260 Theory and modeling
SC: Tectonophysics [T]
MN: 2003 Fall Meeting