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DOI	10.1016/j.tecto.2020.228553
	Estimation of the heterogeneity of stress fields using misfit angles in focal mechanisms
	Yukutake Y.; Iwata T.; Iio Y.
发表日期	2020
ISSN	00401951
卷号	790
英文摘要	The stress field of the Earth's crust is spatially heterogeneous on various scales. The focal mechanism of an earthquake provides important information associated with the stress state at the seismogenic depths. These focal mechanisms are affected by the pore fluid pressure and/or friction coefficient. In this study, we focused on misfit angles, particularly the difference in the angle between the slip direction in an observed focal mechanism and the resolved shear stress direction that can be obtained using the directions of the principal stress axes and the stress ratio of a reference stress field. Resolved shear stress does not depend on the fault friction or pore fluid pressure, allowing us to use misfit angles to evaluate the heterogeneity of stress fields if the effect of an error in a focal mechanism has been properly removed. By statistically evaluating the error in focal mechanisms using a Bayesian approach, we evaluated the misfit angles of the aftershocks of the 2000 Western Tottori Earthquake, in which numerous focal mechanisms could be precisely determined using dense seismic observation. The spatial distribution of the misfit angles of the aftershocks suggested that the stress field in the aftershock region, particularly in the southern portion of the region, was in a heterogeneous state. We also demonstrated that this spatial variability cannot be explained solely by errors in the focal mechanisms. If we assume a uniform stress field before the mainshock, the observed cumulative curve of misfit angles can be explained by coseismic stress changes and the background stress field's depth gradient of differential stress of 3.2 MPa/km. © 2020 Elsevier B.V.
关键词	Aftershock Focal mechanism Heterogeneity in stress field The 2000 Western Tottori Earthquake Uncertainty of a focal mechanism
英文关键词	Bayesian networks; Errors; Friction; Shear flow; Shear stress; Structural geology; Aftershock regions; Bayesian approaches; Differential stress; Friction coefficients; Pore fluid pressure; Seismic observation; Spatial variability; Uniform stress fields; Earthquakes; aftershock; coseismic process; crustal structure; earthquake event; earthquake mechanism; focal mechanism; friction; heterogeneity; pore pressure; seismicity; slip rate; stress field; Chugoku; Honshu; Japan; Tottori [Chugoku]
语种	英语
来源期刊	Tectonophysics
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/207911
作者单位	Hot Springs Research Institute of Kanagawa Prefectural Government, 586 Iriuda Odawara Kanagawa, Japan; Comprehensive Education Center, Prefectural University of Hiroshima, 5562 Nanatsuka-cho Shobara Hiroshima, Japan; The Institute of Statistical Mathematics, 10-3 Midori-cho Tachikawa Tokyo, Japan; Disaster Prevention Research Institute Kyoto University, Gokasho Uji Kyoto, Japan
推荐引用方式 GB/T 7714	Yukutake Y.,Iwata T.,Iio Y.. Estimation of the heterogeneity of stress fields using misfit angles in focal mechanisms[J],2020,790.
APA	Yukutake Y.,Iwata T.,&Iio Y..(2020).Estimation of the heterogeneity of stress fields using misfit angles in focal mechanisms.Tectonophysics,790.
MLA	Yukutake Y.,et al."Estimation of the heterogeneity of stress fields using misfit angles in focal mechanisms".Tectonophysics 790(2020).