气候变化领域集成服务门户(CCPortal): Improved 3-D P Wave Azimuthal Anisotropy Structure Beneath the Tokyo Metropolitan Area, Japan: New Interpretations of the Dual Subduction System Revealed by Seismic Anisotropy

CCPortal

DOI	10.1029/2020JB021194
	Improved 3-D P Wave Azimuthal Anisotropy Structure Beneath the Tokyo Metropolitan Area, Japan: New Interpretations of the Dual Subduction System Revealed by Seismic Anisotropy
	Ishise M.; Kato A.; Sakai S.; Nakagawa S.; Hirata N.
发表日期	2021
ISSN	21699313
卷号	126 期号:3
英文摘要	The Tokyo metropolitan area, in the Kanto region of Japan, lies on the Okhotsk plate. Historically, the city has suffered severe damage as a result of megathrust ruptures and intra-plate earthquakes (M ≥ 7) caused by the dual subduction of the Philippine Sea (PHS) slab and the Pacific slab. To understand the unique seismotectonics of the region, we constrain the three-dimensional (3-D) P wave isotropic and azimuthal anisotropic velocity structure beneath the Kanto district, by applying a high-resolution anisotropic tomography method to travel time data from a dense seismic network consisting of ∼500 stations (including the Metropolitan Seismic Observation network, MeSO-net). The seismic structure, derived from 1,877 local earthquakes, suggests that the basement of the Okhotsk plate consists of an old accretionary zone formed when the NE Japan arc was part of the Asian continent. The anisotropy observed in the oceanic crust of the subducting PHS slab suggests the presence of a well-developed system of bending-related faults, oriented parallel to the axis of the Sagami Trough. We identify a low-velocity anomaly within the PHS slab mantle, located beneath the Boso Peninsula, which has previously been interpreted as representing the overlying continental plate or the oceanic crust of the PHS slab. Lateral variations in the anisotropy structure suggest that the NE limit of the PHS slab lies farther south than previously thought. Anisotropy directions can be used to identify heterogeneities embedded in low-velocity anomalies within the PHS slab, which have not been identified in previous studies using only isotropic velocity models. © 2021. American Geophysical Union. All Rights Reserved.
英文关键词	Japan subduction zone; metropolitan area; Philippine Sea plate; seismic anisotropy; tomography
语种	英语
来源期刊	Journal of Geophysical Research: Solid Earth
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/187277
作者单位	Earthquake Research Institute, The University of Tokyo, Bunkyo City, Japan; Interfaculty Initiative in Information Studies, The University of Tokyo, Bunkyo City, Japan; Research Center for Enhancing Metropolitan Resilience, National Research Institute for Earth Science and Disaster Resilience, Tsukuba, Japan
推荐引用方式 GB/T 7714	Ishise M.,Kato A.,Sakai S.,et al. Improved 3-D P Wave Azimuthal Anisotropy Structure Beneath the Tokyo Metropolitan Area, Japan: New Interpretations of the Dual Subduction System Revealed by Seismic Anisotropy[J],2021,126(3).
APA	Ishise M.,Kato A.,Sakai S.,Nakagawa S.,&Hirata N..(2021).Improved 3-D P Wave Azimuthal Anisotropy Structure Beneath the Tokyo Metropolitan Area, Japan: New Interpretations of the Dual Subduction System Revealed by Seismic Anisotropy.Journal of Geophysical Research: Solid Earth,126(3).
MLA	Ishise M.,et al."Improved 3-D P Wave Azimuthal Anisotropy Structure Beneath the Tokyo Metropolitan Area, Japan: New Interpretations of the Dual Subduction System Revealed by Seismic Anisotropy".Journal of Geophysical Research: Solid Earth 126.3(2021).