DOI: 10.1016/j.epsl.2019.115986
论文题名: Migration of shallow and deep slow earthquakes toward the locked segment of the Nankai megathrust
作者: Uchida N. ; Takagi R. ; Asano Y. ; Obara K.
刊名: Earth and Planetary Science Letters
ISSN: 0012821X
出版年: 2020
卷: 531 语种: 英语
中文关键词: Nankai earthquake
; preseismic slip
; repeating earthquake
; slow earthquake
; slow slip
; southwestern Japan subduction zone
英文关键词: Earthquake effects
; Global positioning system
; Locks (fasteners)
; Offshore oil well production
; Nankai earthquake
; preseismic slip
; Repeating earthquake
; slow slip
; Subduction zones
; Faulting
; earthquake event
; earthquake recurrence
; fault slip
; microtremor
; seismic migration
; spatial distribution
; subduction zone
; temporal distribution
; thrust
; Japan
; Kyushu
; Nankai Trough
; Pacific Ocean
; Shikoku
英文摘要: The Nankai megathrust is located offshore Shikoku and Kyushu, Japan and is characterized by various kinds of slow earthquakes whose relative motions across the plate boundary faults are slower than regular earthquakes. In the area, the interplate locking is stronger in the northern area (offshore Shikoku) than in the southern area (offshore Kyushu) and Mw ∼8 earthquakes (Nankai earthquakes) have occurred repeatedly in the northern area. In this paper, the spatio-temporal distributions of slow earthquakes (very low frequency earthquakes, tremors and slow-slip events) are examined based on the analyses of repeating earthquakes and slow earthquakes with special focus on the interaction between different activities. A comprehensive analysis of the seismic and geodetic data from 2003 to 2016 indicates complementary distribution of various types of slow earthquakes down to 35–50 km depth outside the Nankai main locking area. We also found interactions between different kinds of activities. The interactions between the repeating earthquakes and slow earthquakes suggest that the area of the repeating earthquakes activity can be divided into deeper (depth ≥ 20 km) and shallower (depth < 20 km) areas. The analyses of deep repeating earthquakes and the inland Global Navigation Satellite System (GNSS) data suggests slow northward migrations of long-term slow slip events (SSEs) in 20–50 km (offshore Kyushu) and 20–35 km (under Shikoku) depths along the plate boundary. These migrations occurred during a period of 2–3 years that includes the 2003 and 2010 large slow-slip events in the Bungo channel located in between Kyushu and Shikoku. The analysis has also shown interaction between shallow repeating earthquakes and shallow very low frequency earthquakes which indicates faster northward migrations of short-term SSEs from the shallow plate boundary offshore Kyushu to the deeper area under Shikoku over the duration of a month during the 2010 long-term slow-slip episode. The deep slow migration and the shallow to deep fast migration of SSEs in a ∼300 km area towards and around the source area of the recurrent Nankai earthquake (Mw 8.0–8.6) indicates the occurrence of a widespread non-steady stress build-up process around the source area of the Nankai megathrust earthquake. © 2019 The Authors Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/165318
Appears in Collections: 气候变化与战略
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作者单位: Graduate School of Science, Tohoku University, 6-6 Aramaki-aza-aoba, Aoba-ku, Sendai, 980-8578, Japan; National Research Institute for Earth Science and Disaster Resilience, 3-1 Tennodai, Tsukuba, Ibaraki 305-0006, Japan; Earthquake Research Institute, University of Tokyo, Bunkyo, Tokyo, 113-0032, Japan
Recommended Citation:
Uchida N.,Takagi R.,Asano Y.,et al. Migration of shallow and deep slow earthquakes toward the locked segment of the Nankai megathrust[J]. Earth and Planetary Science Letters,2020-01-01,531