A new mechanical perspective on a shallow megathrust near-trench slip from the high-resolution fault model of the 2011 Tohoku-Oki earthquake

• DOI: 10.1186/s40645-022-00524-0
• Publication Date: 2022-12-05T09:03:47Z
• Authors: Tatsuya Kubota; Tatsuhiko Saito; Ryota Hino
• Keywords: QE1-996.5; Tsunami; Geology; The 2011 Tohoku-Oki earthquake; 01 natural sciences; G; Geography. Anthropology. Recreation; Ocean-bottom pressure gauge; Stress drop; Frictional strength of megathrust; Plate mechanical coupling; 0105 earth and related environmental sciences

Abstract The 2011 Tohoku-Oki earthquake generated a surprisingly large near-trench slip, and earth scientists have devoted significant attention to understanding why. Some studies proposed special rupture mechanisms, such as extensive dynamic frictional weakening; others simulated this slip behavior without supposing the weakening. However, we not reached decisive conclusion for question due limited spatial resolution. Hence, in study use new tsunami data recorded just above area addition offshore onshore geodetic improve resolution of stress release quantitatively examine mechanical state plate interface. A maximum 53 m reaching trench an insignificant drop (< 3 MPa) at shallowest portion fault were estimated. Based on our modeling results past experimental studies, it is suggested that friction shallow should be inherently low both before during earthquake. This result provides perspectives along boundary, which strain energy accumulation deep accounts anomalous but coupling does not. has been considered sufficiently interface, suggest slips similar may occur any subduction zones where accumulates only deeper portion.