DOI: 10.1016/j.tecto.2020.228501
论文题名: A reappraisal of the 2005 Kashmir (Mw 7.6) earthquake and its aftershocks: Seismotectonics of NW Himalaya
作者: Powali D. ; Sharma S. ; Mandal R. ; Mitra S.
刊名: Tectonophysics
ISSN: 00401951
出版年: 2020
卷: 789 语种: 英语
中文关键词: Aftershocks
; Coulomb failure stress
; High frequency back-projection
; Kashmir earthquake
; Seismo-tectonics
; Source mechanism
英文关键词: Faulting
; 2005 Kashmir earthquake
; Coulomb failure stress
; Coulomb stress changes
; Integrated sources
; Rupture propagation
; Rupture velocities
; Spatiotemporal evolution
; Waveform inversion
; Earthquakes
; aftershock
; earthquake event
; earthquake magnitude
; earthquake rupture
; fault zone
; seismic source
; seismic velocity
; seismotectonics
; India
; Jammu and Kashmir
英文摘要: We study the source properties of the 2005 Kashmir earthquake and its aftershocks to unravel the seismotectonics of the NW Himalayan syntaxis. The mainshock and larger aftershocks have been simultaneously relocated using phase data. We use back-projection of high-frequency energy from multiple teleseismic arrays to model the spatio-temporal evolution of the mainshock rupture. Our analysis reveal a bilateral rupture, which initially propagated SE and then NW of the epicenter, with an average rupture velocity of ~2 km s−1. The area of maximum energy release is parallel to and bound by the surface rupture. Incorporating rupture propagation and velocity, we model the mainshock as a line source using P- and SH-waveform inversion. Our result confirms that the mainshock occurred on a NE dipping (~35°) fault plane, with centroid depth of ~10 km. Integrated source time function show that majority of the energy was released in the first ~20 s, and was confined above the hypocenter. From waveform inverted fault dimension and seismic moment, we argue that the mainshock had an additional ~25 km blind rupture beyond the NW Himalayan syntaxis. Combining this with findings from previous studies, we conjecture that the blind rupture propagated NW of the syntaxis underneath a weak detachment, overlain by infra-Cambrian salt layer, and terminated in a wedge thrust. All moderate-to-large aftershocks, NW of the mainshock rupture, are concentrated at the edge of the blind rupture termination. Source modeling of these aftershocks reveal thrust mechanism with centroid depths of 2–10 km, and fault planes oriented sub-parallel to the mainshock rupture. To study the influence of mainshock rupture on aftershock occurrence, we compute Coulomb failure stress on aftershock faults. All these aftershocks lie in the positive Coulomb stress change region. This suggest that the aftershocks have been triggered by either co-seismic or post-seismic slip on the mainshock fault. © 2020 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/170684
Appears in Collections: 气候变化与战略
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作者单位: Department of Earth Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, West Bengal 741246, India; Center for Climate and Environmental Studies, Indian Institute of Science Education and Research Kolkata, Mohanpur, West Bengal 741246, India; Institute of Geosciences, University of Potsdam, Am Neuen Palais 10, Potsdam, 14469, Germany; GFZ German Research Centre for Geosciences, Potsdam, D-14473, Germany
Recommended Citation:
Powali D.,Sharma S.,Mandal R.,et al. A reappraisal of the 2005 Kashmir (Mw 7.6) earthquake and its aftershocks: Seismotectonics of NW Himalaya[J]. Tectonophysics,2020-01-01,789