DOI: 10.1002/2015GL067034
论文题名: Improving back projection imaging with a novel physics-based aftershock calibration approach: A case study of the 2015 Gorkha earthquake
作者: Meng L. ; Zhang A. ; Yagi Y.
刊名: Geophysical Research Letters
ISSN: 0094-9456
EISSN: 1944-9187
出版年: 2016
卷: 43, 期: 2 起始页码: 628
结束页码: 636
语种: 英语
英文关键词: aftershock calibration
; back projection
; Gorhka earthquake
Scopus关键词: Calibration
; Geophysics
; Location
; Uncertainty analysis
; Back projection
; Back-projection imaging
; Inter-seismic periods
; Propagation direction
; Regional networks
; Seismogenic zones
; Spatial uncertainty
; Technical improvement
; Earthquakes
; aftershock
; calibration
; decollement
; dip
; earthquake rupture
; Gorkha earthquake 2015
; seismic zone
; three-dimensional modeling
; Australia
; Bihar
; Europe
; Himalayas
; India
; Nepal
; North America
英文摘要: The 2015 Mw 7.8 Nepal-Gorkha earthquake with casualties of over 9000 people was the most devastating disaster to strike Nepal since the 1934 Nepal-Bihar earthquake. Its rupture process was imaged by teleseismic back projections (BP) of seismograms recorded by three, large regional networks in Australia, North America, and Europe. The source images of all three arrays reveal a unilateral eastward rupture; however, the propagation directions and speeds differ significantly between the arrays. To understand the spatial uncertainties of the BP analyses, we analyze four moderate size aftershocks recorded by all three arrays exactly as had been conducted for the main shock. The apparent source locations inferred from BPs are systematically biased from the catalog locations, as a result of a slowness error caused by three-dimensional Earth structures. We introduce a physics-based slowness correction that successfully mitigates the source location discrepancies among the arrays. Our calibrated BPs are found to be mutually consistent and reveal a unilateral rupture propagating eastward at a speed of 2.7 km/s, localized in a relatively narrow and deep swath along the downdip edge of the locked Himalayan thrust zone. We find that the 2015 Gorkha earthquake was a localized rupture that failed to break the entire Himalayan décollement to the surface, which can be regarded as an intermediate event during the interseismic period of larger Himalayan ruptures that break the whole seismogenic zone width. Thus, our physics-based slowness correction is an important technical improvement of BP, mitigating spatial uncertainties and improving the robustness of single and multiarray studies. © 2016. American Geophysical Union. All Rights Reserved. URL: https://www.scopus.com/inward/record.uri?eid=2-s2.0-84958068735&doi=10.1002%2f2015GL067034&partnerID=40&md5=f398ea3fae6ef25b2a813cc74a792ec3
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资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/10419
Appears in Collections: 科学计划与规划 气候变化与战略
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作者单位: Earth, Planetary, and Space Sciences, University of California, Los Angeles, CA, United States
Recommended Citation:
Meng L.,Zhang A.,Yagi Y.. Improving back projection imaging with a novel physics-based aftershock calibration approach: A case study of the 2015 Gorkha earthquake[J]. Geophysical Research Letters,2016-01-01,43(2).