Detection of asperities and barriers East off Tohoku.

在三维动态裂隙模型的基础上，结合前人的波形反演结果，研究了1968年东京奥基地震的动态破裂过程。在断层滑动边界条件下，通过求解三维平衡方程，估算了应力降的分布。并估算了强度过剩分布和断裂韧度(临界应力强度因子)分布。高应力降区域和高强度过剩区域分别对应于粗糙度和势垒。我们为这次活动找到了两个障碍和三个凹凸不平的地方。与地形、地震活动、重力和热流资料对比，似乎障碍之一位于复杂的地表地形上。

Dynamic rupture process of the 1968 Tokachi-Oki earthquake has been investigated on the bais of a three-dimensional dynamic crack model with constraints of the results of previous waveform inversion. The stress drop distribution has been estimated by solving 3D equilibrium equations with the boundary condition of slip on the fault. The strength excess distribution and fracture toughness (critical stress intensity factor) distribution have been also estimated. The high stress drop regions and high strength excess regions, correspond asperities and barrier, respectively. We found two barriers and three asperities for the event. Comraring with topography, seismicity, gravity, and heat flow data, it seems that one of the barriers locates at the complicated surface topography.