摘要:Repeating M 5-class earthquakes occurred with a regular recurrence interval on the plate boundary offshore Kamaishi before the 2011 M 9 Tohoku-oki earthquake.Since this event, 11 repeating events of M 5– M 6 have occurred with shorter recurrence intervals than before the M 9 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 I th 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 sequences were used as ensemble forecasts.We attempted to predict the 7th event to the 11th event and discussed the obtained forecast spreads and errors.
关键词:Kamaishi repeating earthquakes; Forecast experiment; Afterslip; The 2011 Tohoku-oki earthquake