Large intraslab earthquake 2011 April 7, M 7.1 after the 2011 off the Pacific coast of Tohoku Earthquake M 9.0: Coseismic fault model based on the dense GPS network dataReport as inadecuate




Large intraslab earthquake 2011 April 7, M 7.1 after the 2011 off the Pacific coast of Tohoku Earthquake M 9.0: Coseismic fault model based on the dense GPS network data - Download this document for free, or read online. Document in PDF available to download.

Earth, Planets and Space

, Volume 63, Issue 12, pp 1207–1211

First Online: 21 February 2012Received: 09 June 2011Revised: 09 July 2011Accepted: 24 July 2011

Abstract

We propose a source fault model for the 2011, April 7, earthquake M 7.1 deduced from a dense GPS network. The coseismic displacements obtained by GPS data analysis clearly show the spatial pattern specific to intraslab earthquakes, not only in the horizontal components but also the vertical ones. A rectangular fault with uniform slip was estimated by a non-linear inversion approach. The results indicate that the simple rectangular fault model can explain the overall features of the observations. The amount of moment released is equivalent to Mw 7.17. The hypocenter depth of the main shock estimated by the Japan Meteorological Agency is slightly deeper than the neutral plane between down-dip compression DC and down-dip extension DE stress zones of the double-planed seismic zone. This suggests that the depth of the neutral plane was deepened by the huge slip of the 2011, M 9.0, Tohoku Earthquake, and the rupture of the thrust M 7.1 earthquake was initiated at that depth, although more investigations are required to confirm this idea. The estimated fault plane has an angle of ∼60 degrees from the surface of the subducting Pacific plate. It is consistent with the hypothesis that intraslab earthquakes are thought to be a reactivation of the pre-existing hydrated weak zones produced in the bending process of oceanic plates around outer-rise regions.

Key wordsIntraslab earthquake 2011 off the Pacific coast of Tohoku Earthquake GPS  Download fulltext PDF



Author: Yusaku Ohta - Satoshi Miura - Mako Ohzono - Saeko Kita - Takeshi Iinuma - Tomotsugu Demachi - Kenji Tachibana - Takashi Na

Source: https://link.springer.com/







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