Experimental study on mechanical properties of plate interface of the northeastern Japan subduction zone

2014 Fiscal Year Final Research Report

• Project/Area Number: 24244077
• Research Category: Grant-in-Aid for Scientific Research (A)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Geology
• Research Institution: Tohoku University
• Principal Investigator: NAGAHAMA Hiroyuki 東北大学, 理学(系)研究科(研究院), 教授 (60237550)
• Co-Investigator(Kenkyū-buntansha): MUTO Jun 東北大学, 大学院理学研究科, 助教 (40545787) ; NAGASE Toshiro 東北大学, 学術資源公開センター, 准教授 (10237521) ; SHIMIZU Ichiko 東京大学, 大学院理学系研究科, 助教 (40211966)
• Project Period (FY): 2012-04-01 – 2015-03-31
• Keywords: 東北地方太平洋沖地震 / 沈み込み帯 / プレート境界地震 / レオロジー / 余効変動 / 岩石力学 / 固体圧岩石変形試験機 / ガス圧岩石変形試験機

Outline of Final Research Achievements

In order to reveal the mechanism of the 2011 Tohoku Oki earthquake and subsequent post-seismic deformation of the northeastern Japan, we have conducted deformation experiments of a wide variety of rocks composing subduction zones. By the friction experiments using gas rig, frictional stability of quartz gouge is observed to be correlated to energy ratio of the gouge controlled by internal structure of gouges. Moreover, rupture velocity of serpentinites and olivine gouges depends on the their frictional coefficients and normal stress, implying that the slow slip in subduction zones illuminates the stress state of the plate boundary. By the shear experiments using Griggs rig, deformation mechanisms and creep strengths of feldspars are significantly reduced by the presence of water added externally into the samples under the lower crustal condition. We also proposed rheological models of the NE Japan island arc-trench systems and plate boundary causing the 2011 Tohoku Oki earthquake.

Free Research Field

構造地質学