Relocating the 2011 Tohoku-oki earthquakes (M 6.0-9.0)

详细信息    查看全文

• 作者：Zhouchuan Huang ; ^{zhouchuan.huang@gmail.com} ; Dapeng Zhao ; ^{zhao@aob.gp.tohoku.ac.jp}
• 关键词：Earthquake location ; Subduction zones ; Pacific slab ; Megathrust zone ; Asperity ; Stress field
• 刊名：Tectonophysics
• 出版年：2013
• 出版时间：26 February, 2013
• 年：2013
• 卷：586
• 期：Complete
• 页码：35-45
• 全文大小：2761 K

文摘

The great Tohoku-oki earthquake (Mw 9.0) on 11 March 2011 was accompanied by nearly 100 large foreshocks and aftershocks (M ¡Ý 6.0) in the Northeast Japan forearc. In this study we relocated 77 of these large events using three different velocity models. An updated three-dimensional velocity model significantly reduced the travel-time residuals in the earthquake relocation. We found that the large thrust earthquakes are generally located in or around high-velocity patches, suggesting that the generation of the large thrust earthquakes is controlled by structural heterogeneities in the megathrust zone. The high-velocity patches may represent asperities in the megathrust zone where the subducting Pacific plate and the overriding Okhotsk plate may be coupled strongly. Many non-thrust earthquakes occurred in the crust of the overriding Okhotsk plate, indicating that the stress field there has been changed by the Tohoku-oki mainshock. The present results may improve our understanding of the subduction dynamics and seismotectonics of the Northeast Japan arc.