[SSS04-P08] Source rupture process and strong motion generation areas for the 2018 Hokkaido Eastern Iburi earthquake
Keywords:The 2018 Hokkaido Eastern Iburi earthquake, Rupture process, Strong motion generation area
From the results of these source models and ground motion simulation, our principal findings are following. 1) The main large ground motions observed at near-source stations were generated by the up-dip rupture in the large slip area (i.e., the asperity area) identified at the depth shallower than the hypocenter, which coincides with the position of the SMGA1. 2) The SMGA2 and 3 played a key role to generate the observed later phases, which are not explained enough only by the SMGA1 or asperity area. 3) The estimated stress drop or short-period level, which control the high-frequency ground motion radiations, were larger than the average value of past large crustal earthquakes usually occurring in Japan. These findings are important to understand the source characteristics of the earthquakes occurring at deep depth in arc-arc collision tectonic zone.
Acknowledgements: The strong motion data from K-NET, KiK-net, and F-net were provided by the National Research Institute for Earth Science and Disaster Resilience (NIED). We also used the strong motion data from the seismic intensity observation networks of the JMA, Moment tensor solutions were routinely determined by F-net. The JMA unified earthquake catalog was produced by the JMA in cooperation with the Ministry of Education, Culture, Sports, Science and Technology (MEXT). This study was based on the 2019 research project “Examination for uncertainty of strong ground motion prediction for inland crustal earthquakes” by The Secretariat of the Nuclear Regulation Authority (NRA), Japan.