Numerical simulation study on recent changes in crustal deformation and seismicity in the Tokai area, central Japan
Abstract
Recently, Tada(1996) and Matsumura(2000) reported that crustal deformation rate and seismicity pattern have changed interestingly in the Tokai area, central Japan. We formulate a recurring earthquake model in the Tokai area based on the rate- and state dependent frictional law derived from laboratory experiments on rock friction and on the location of a seismically locked region. Using model parameters based on previous studies, we estimate the time when the next Tokai Earthquake will occur and the location of the plate interface by fitting a simulated calculation to observed data. Some of the results explain the recent decrease in the rate of uplift change, especially at the three observational points. We find that the mechanism of microearthquakes is explained well by the temporal change of the stress field. The present model shows the vertical rotation of the axes of principal stresses and predicts the precursory change of seismic activity in the depth range of 10-20km in the region where the distance from the assumed trench along the relative plate motion direction is about 150km. The present seismicity with P axis almost horizontal will become more inactive several years before the occurrence of a great earthquake, and/or the direction of P axis rotates abruptly about 80 degrees to be orthogonal to plate interface.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2001
- Bibcode:
- 2001AGUFM.S52C0630K
- Keywords:
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- 1242 Seismic deformations (7205);
- 7223 Seismic hazard assessment and prediction;
- 7230 Seismicity and seismotectonics