日本9.0级地震断层分布和错动方式探讨

摘要

The dynamic environment of the Ms9.0 earthquake off the east coast of Honshu,Japan preliminarily discussed by using Japanese lacal geological structure, plate tectonics, post and co-smemic displacement at GPS stations in Japan area, focal mechanisms and so on. It can be compresses judged that the earthquake might happen in this way that the Pacific plate dives and compresses to below Eurasian plate, the stress between Pacific plate and Eurasian plate accumulates along with time, when the stress/strain intensity exceeds friction intensity or stress intensity of rock,thus the fault which at the depth of 10 -20 km in the Eurasian plate became a thrust fault whose dip angle less than Wadati-Benioff belt's, and the earthquake occared. This earthquake makes a fault zone with about 600 km length and nearly the same strike as Wadati-Benioff' s. The fault zone located at the boundary between Pacific plate and Eurasian plate close to south-north strike.%结合日本区域地质构造、板块运动、震源附近日本区域GPS站点同震位移,及余震震源机制解,对日本9.0级地震的断层分布和错动方式进行了探讨,初步推断此次地震可能是太平洋板块向欧亚板块下方俯冲和挤压,造成板块边界附近应力不断集中,当应力/应变强度超过摩擦强度或岩石的破裂强度时,在欧亚板块内部深度为10～20 km范围内、倾角略低于Wadati-Benioff带俯冲倾角的断层面上产生逆冲错动而致,同时形成了和Wadati-Benioff带走向一致、长达约600 km的破裂带.