Mechanism of the 2011 Tohoku-oki earthquake (Mw 9.0) and tsunami: Insight from seismic tomography |
| |
Institution: | 1. Institute of Geophysics, China Earthquake Administration, Beijing 100081, PR China;1. Instituto Geofísico y Sismológico Ing. Volponi, Universidad Nacional de San Juan, Ruta 12-Km17, San Juan, Argentina;2. Consejo Nacional de Investigaciones Cientifícas y Técnicas, CONICET, Argentina;3. Fondo Argentino Sectorial, Agencia de Promoción Científica y Tecnológica, FONARSEC, Argentina;4. INDEAN - Instituto de Estudios Andinos “Don Pablo Groeber”. Departamento de Cs. Geológicas - FCEN - Pab. II. Universidad de Buenos Aires, Argentina;5. Department of Mathematics and Geosciences, University of Trieste, Via Weiss, I-34127 Trieste, Italy |
| |
Abstract: | To clarify the generating mechanism of the 2011 Tohoku-oki earthquake (Mw 9.0) and the induced tsunami, we determined high-resolution tomographic images of the Northeast Japan forearc. Significant lateral variations of seismic velocity are visible in the megathrust zone, and most large interplate thrust earthquakes are found to occur in high-velocity (high-V) areas. These high-V zones may represent high-strength asperities at the plate interface where the subducting Pacific plate and the overriding Okhotsk plate are coupled strongly. A shallow high-V zone with large coseismic slip near the Japan Trench may account for the mainshock asperity of the 2011 Tohoku-oki earthquake. Because it is an isolated asperity surrounded by low-velocity patches, most stress on it was released in a short time and the plate interface became decoupled after the Mw 9.0 earthquake. Thus the overriding Okhotsk plate there was shot out toward the Japan Trench and caused the huge tsunami. |
| |
Keywords: | Tohoku-oki earthquake Northeast Japan Seismic tomography Megathrust zone Seismotectonics Asperity Plate coupling |
本文献已被 ScienceDirect 等数据库收录! |
|