HR: 1340h
AN: S13A-1046    [Abstracts]
TI: Successful Forecast of the Place of Great Solomon Islands Earthquake of April 1, 2007, Mw8.1
AU: * Purcaru, G
EM: purcaru@geophysik.uni-frankfurt.de
AF: Univ. of Frankfurt/Main, Inst. of Geosciences, Rheinstr. 11, Frankfurt/Main, 60325, Germany
AB: Predicting the large and great earhquakes proved to remain at present a complicated and most difficult problem, regarding the place and magnitude, and especially the time, on medium- or long-term interval, which is the principal component of any prediction. As a result a few (scientific) predictions are really successful, with a desired precision. False alarms and failures are by far dominant. However, the incresed number of higher accuracy data, advancements in the rupture- imaging at a smaller scale, seimotectonics details, increase of GPS data, different deterministic and probabilistic methods and numerical experimnts, retrospective predictions, etc. All these have to contribute, to increase a knowledge necessary to find better prediction-laws and methods in order to make particular earthquakes in specified regions more predictable. Along this view, we present a successful prediction (deterministic prediction) of a large earthquake in the Solomon Islands subduction zone: 154°E to 165°le E, where large earthquakes are occurring. We analized in detail historical earthquakes and aftershock areas (Kelleher et al, 1973, 1974; McCann et al 1979; Lay and Kanamori, 1980) of large events, their distribution and space and time, and the fluctuations of earthquake activity. We identified, in 1984, a seismic gap in the Central region of the subduction zone, with the boundary to NW: 156°E and to SE: 157°E. Its dimension (L = 180Km) corresponds to a magnitude of 7.8-8.0. No time prediction was made. The gap bundaries were fixed to NW at the SE-end of aftershock areas of the Jan - Feb. 1974 earthquake doublet (M7.0, M7.1) and to SE at the location of the Jan. 30, 1939 (Ms7.9-8.0) and its aftersock area was not known. The 2007 Solomon epicenter is well inside the gap. No evidence or rationale at that times would at least suggest that a future large earthquake in the gap will possibly rupture further to NW, and if the contrary than it is only a coincidence. Therefore the forecasted earthquake has closed very well the gap. The 6-days (also the 8-days) earthquake aftershock zone (PDE - data), 155°E - 157.5°E, is grater than that of the gap. This interval is very well consistent with the lengths of rupture models based on different inversion methods (C. Ji, Sanchu, Y. Yagi). Also we found the gap remained very stable until the occurrence of the 2007 Solomon earthquake. Fnally, a new seismic gap, bounded 158°E - 160°E, is proposed following the 2007 event. If the 1939 earthquake occurred in this gap is, however, presently unknown to us. If strong evidence can support the 1939 rupture place in the gap, then the future earthquake will close the first known seismic cycle for this plate boundary segment. The space-time evolution of the gap must therefore be continously under observation and further analyzed.
UR: http://www.agu.org
DE: 1217 Time variable gravity (7223, 7230)
DE: 1240 Satellite geodesy: results (6929, 7215, 7230, 7240)
DE: 1242 Seismic cycle related deformations (6924, 7209, 7223, 7230)
DE: 1734 Seismology
SC: Union [U]
MN: 2007 Fall Meeting