DOI: 10.1002/2016GL070283
论文题名: Evidence for Moho-lower crustal transition depth diking and rifting of the Sierra Nevada microplate
作者: Smith K.D. ; Kent G.M. ; von Seggern D.P. ; Driscoll N.W. ; Eisses A.
刊名: Geophysical Research Letters
ISSN: 0094-8488
EISSN: 1944-8219
出版年: 2016
卷: 43, 期: 20 起始页码: 10738
结束页码: 10744
语种: 英语
英文关键词: Basin and Range
; diking
; Moho-transition depth seismicity
; rifting
; Sierra microplate
Scopus关键词: Earthquakes
; Geophysics
; Hydraulic structures
; Levees
; Structural geology
; Basin and range
; diking
; Microplates
; Moho-transition depth seismicity
; rifting
; Tectonics
英文摘要: Lithospheric rifting most often initiates in continental extensional settings where “breaking of a plate” may or may not progress to sea floor spreading. Generally, the strength of the lithosphere is greater than the tectonic forces required for rupture (i.e., the “tectonic force paradox”), and it has been proposed that rifting requires basaltic magmatism (e.g., dike emplacement) to reduce the strength and cause failure, except for the case of a thin lithosphere (<30 km thick). Here we isolate two very similar and unprecedented observations of Moho-lower crustal transition dike or fluid injection earthquake swarms under southern Sierra Valley (SV: 2011–2012) and North Lake Tahoe (LT: 2003–2004), California. These planar distributions of seismicity can be interpreted to define the end points, and cover ~25% of the length, of an implied ~56 km long structure, each striking N45°W and dipping ~50°NE. A single event at ~30 km depth that locates on the implied dipping feature between the two swarms is further evidence for a single Moho-transition depth structure. We propose that basaltic or fluid emplacement at or near Moho depths weakens the upper mantle lid, facilitating lithospheric rupture of the Sierra Microplate. Similar to the LT sequence, the SV event is also associated with increased upper crustal seismicity. An 27 October 2011, Mw 4.7 earthquake occurred directly above the deep SV sequence at the base of the upper crustal seismogenic zone (~15 km depth). ©2016. The Authors. URL: https://www.scopus.com/inward/record.uri?eid=2-s2.0-84995554266&doi=10.1002%2f2016GL070283&partnerID=40&md5=befd1314a931c3d831b83e67366207c1
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资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/9451
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: Nevada Seismological Laboratory, University of Nevada, Reno, Reno, NV, United States
Recommended Citation:
Smith K.D.,Kent G.M.,von Seggern D.P.,et al. Evidence for Moho-lower crustal transition depth diking and rifting of the Sierra Nevada microplate[J]. Geophysical Research Letters,2016-01-01,43(20).