地震・噴火予知研究観測センター 趙大鵬教授が "Dapeng Zhao, M. Santosh and Akira Yamada, 2010. Dissecting large earthquakes in Japan: Role of arc magma and fluids. Island Arc, 19, 4-16" により、２０１４年度日本地質学会 Island Arc賞 を受賞しました。
"Dapeng Zhao, M. Santosh and Akira Yamada, 2010. Dissecting large earthquakes in Japan: Role of arc magma and fluids. Island Arc, 19, 4-16"
Dr. Zhao and the co-authors have tried to clarify causal mechanisms of large earthquakes in the Japanese Islands using high-resolution tomographic images of the crust and uppermost part of the mantle beneath the mainshock hypocenters of the large earthquakes during 1995 to 2008. They have found that the large earthquakes, as well as 164 additional crustal earthquakes, have occurred along low-velocity zones with high Poisson's ratio anomalies, which are considered to be represented by arc magma and fluid. The finding indicates that the generation of a large earthquake is not entirely a mechanical process, but is closely related to the physical and chemical properties of materials of the crust and upper mantle, such as magma and fluids, which are produced by a combination of subducting slab dehydration and corner flow in the mantle wedge. Furthermore, the authors have pointed out that the rupture nucleation zone should have a three-dimensional spatial extent and is not just limited to the two-dimensional surface of a fault as suggested by the previous studies. The outcome of this study should contribute to a better understanding of the origin and mechanisms of large earthquakes and also be indispensable for the mitigation of large earthquake-related disasters in the future.
This paper received the highest number of citations-based on the Thomson Science Index for the year 2013-amongst the entire candidate Island Arc papers published in 2010-2012. The first author has been active in the research of seismic tomography and the effects of fluids and magma on earthquakes. This paper adds to his many contributions and is a worthy receipt of the 2013 Island Arc Award.