[S-SS04] Earthquake prediction and forecast

[SSS04-P05] Validation of forecast experiment on the Kamaishi repeating earthquakes based on numerical simulations

*Shingo Yoshida¹, Jun'ichi Fukuda¹, Toshihiro Igarashi¹ (1.Earthquake Research Institute, University of Tokyo)

Keywords: Kamaishi repeating earthquakes, forecast experiment

Repeating M5-class earthquakes occurred with a regular recurrence interval on the plate boundary offshore Kamaishi before the 2011 M9 Tohoku-oki earthquake. Since this event, repeating events of M5 to M6 occurred with shorter recurrence intervals than before the M9 event. We performed a forecast experiment on the Kamaishi repeaters after the Tohoku-oki earthquake based on numerical simulations assuming a large patch containing a small patch on a fault model that undergoes continuous afterslip.Simulations were conducted for various parameter values to produce time history of repeated ruptures.To forecast the Ith event, we selected several modeled sequences that are able to accurately reproduce the observed event sequence up to the (I-1)th event. The averages of the occurrence times and magnitudes over the selected sequenceswere used as ensemble forecasts. Yoshida, Kato, and Fukuda (2016) attempted to predict the 7th event to the 11th event. In addition, the occurrence time of the 12th event, which did not occur before the publication of this paper, was forecasted. In this study, we discuss the forecast result.