2017 Volume 17 Issue 2 Pages 2_1-2_22
This study is aiming to construct source model for simulating long-period motions (2-10 seconds) that cause damage of long-period structures (e.g. Skyscrapers, and large petroleum storage tanks) for mega-thrust subduction earthquakes. The large slip area caused catastrophic tsunamis was located on the shallow area near the Japan trench during the 2011 Tohoku earthquake. On the other hand, the strong motion generation area (SMGA) generating the strong motions were located west of the hypocenter and along the down-dip edge of the source fault. We clarified that ground motions from the SMGAs have the omega-squared spectral characteristics including long-periods from 2 to 10 s of engineering interest, analyzing the observed records identified as wavepackets from the SMGAs Then, we propose a method of evaluating the long-period ground motions from the SMGAs using an appropriate subfault size and slip velocity time functions to be able to follow the omega-square scaling model.
