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Meteorological Research Institute, Japan Meteorological Agency, 1-1 Nagamine, Tsukuba, Ibaraki 305-0052, Japan
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- PublicationOpen AccessStructural control on the Tohoku earthquake rupture process investigated by 3D FEM, tsunami and geodetic data(2014-07-09)
; ; ; ; ; ; ; ; ; ; ;Romano, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Trasatti, E.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia ;Lorito, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Piromallo, C.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Piatanesi, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Ito, Y.; Disaster Prevention Research Institute, Kyoto University, Japan ;Zhao, D.; Department of Geophysics, Tohoku University, Sendai, Japan ;Hirata, K.; National Research Institute for Earth Science and Disaster Prevention, Ibaraki, Japan ;Lanucara, P.; CINECA, SuperComputing Applications and Innovation Department - SCAI, Rome, Italy ;Cocco, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; ; ; ; ; ; ; ; ; The 2011 Tohoku earthquake (Mw = 9.1) highlighted previously unobserved features for megathrust events, such as the large slip in a relatively limited area and the shallow rupture propagation. We use a Finite Element Model (FEM), taking into account the 3D geometrical and structural complexities up to the trench zone, and perform a joint inversion of tsunami and geodetic data to retrieve the earthquake slip distribution. We obtain a close spatial correlation between the main deep slip patch and the local seismic velocity anomalies, and large shallow slip extending also to the North coherently with a seismically observed low-frequency radiation. These observations suggest that the friction controlled the rupture, initially confining the deeper rupture and then driving its propagation up to the trench, where it spreads laterally. These findings are relevant to earthquake and tsunami hazard assessment because they may help to detect regions likely prone to rupture along the megathrust, and to constrain the probability of high slip near the trench. Our estimate of ~40 m slip value around the JFAST (Japan Trench Fast Drilling Project) drilling zone contributes to constrain the dynamic shear stress and friction coefficient of the fault obtained by temperature measurements to ~0.68 MPa and ~0.10, respectively.1288 127 - PublicationRestrictedClues from joint inversion of tsunami and geodetic data of the 2011 Tohoku-oki earthquake(2012-04-27)
; ; ; ; ; ; ; ; ;Romano, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Piatanesi, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Lorito, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;D'Agostino, N.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia ;Hirata, K.; Meteorological Research Institute, Japan Meteorological Agency, 1-1 Nagamine, Tsukuba, Ibaraki 305-0052, Japan ;Atzori, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia ;Yamazaki, Y.; Department of Ocean and Resource Engineering, University of Hawaii at Manoa, Honolulu, Hawaii, USA ;Cocco, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; ; ; ; ; ; ; The 2011 Tohoku-oki (Mw 9.1) earthquake is so far the best-observed megathrust rupture, which allowed the collection of unprecedented offshore data. The joint inversion of tsunami waveforms (DART buoys, bottom pressure sensors, coastal wave gauges, and GPS-buoys) and static geodetic data (onshore GPS, seafloor displacements obtained by a GPS/acoustic combination technique), allows us to retrieve the slip distribution on a non-planar fault. We show that the inclusion of near-source data is necessary to image the details of slip pattern (maximum slip ,48 m, up to ,35 m close to the Japan trench), which generated the large and shallow seafloor coseismic deformations and the devastating inundation of the Japanese coast. We investigate the relation between the spatial distribution of previously inferred interseismic coupling and coseismic slip and we highlight the importance of seafloor geodetic measurements to constrain the interseismic coupling, which is one of the key-elements for long-term earthquake and tsunami hazard assessment.340 26