1994 Fiscal Year Final Research Report Summary

Detection of asperities and barriers East off Tohoku.

Research Project

Project/Area Number	05640462
Research Category	Grant-in-Aid for General Scientific Research (C)
Allocation Type	Single-year Grants
Research Field	固体地球物理学
Research Institution	University of Tokyo
Principal Investigator	MIYATAKE Takashi Univ.of Tokyo, Earthq.Res.Inst., Associate Professor, 地震研究所, 助教授 (60126183)
Project Period (FY)	1993 – 1994
Keywords	Seismic source process / Dynamic rupture / Tokachi-Oki earthquake / Asperity / Barrier
Research Abstract	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.

(2 results)