SENSITIVITY OF TSUNAMI HEIGHT DISTRIBUTION TO FAULT MODEL PARAMETERS: CASE STUDY BASED ON THE 2016 OFF FUKUSHIMA EARTHQUAKE

Abstract

 The intraplate earthquake that occurred off the coast of Fukushima Prefecture on November 22, 2016 was a normal fault type earthquake whose fault extended in the northeast-to-southwest direction. The strike parameter of its seismic fault was different from that of the north-to-south direction assumed for this area by the tsunami database prepared, at that time, by the Japan Meteorological Agency for the tsunami warning operation. To examine the effect on the tsunami forecasting of the occurrence of an earthquake different from the assumption, this study analyzes the sensitivity of the tsunami height distribution to fault model parameters including the strike. According to the interpretation from the extent of sensitivity to each parameter obtained based on the case study of the 2016 off Fukushima earthquake, the typical prediction error of the tsunami height owing to the different strike assumption of approximately 45° is equivalent to the difference of tsunami heights owing to the wrong determination of the dip angle of 45° and vertical. Or, it is comparable to the prediction error when the centroid is mistakenly determined as approximately as half of the fault length apart.