DOI: 10.1002/2015GL067173
论文题名: Constraints on the source parameters of low-frequency earthquakes on the San Andreas Fault
作者: Thomas A.M. ; Beroza G.C. ; Shelly D.R.
刊名: Geophysical Research Letters
ISSN: 0094-9372
EISSN: 1944-9103
出版年: 2016
卷: 43, 期: 4 起始页码: 1464
结束页码: 1471
语种: 英语
英文关键词: low-frequency earthquake
; San Andreas Fault
; slow slip
; stress drop
Scopus关键词: Drops
; Earthquakes
; Faulting
; Geophysics
; Shear flow
; Shear waves
; Strike-slip faults
; Velocity
; Low-frequency earthquakes
; Orders of magnitude
; Repeating earthquake
; Rupture velocities
; San Andreas fault
; Slow slip
; Source parameters
; Stress drop
; Fault slips
英文摘要: Low-frequency earthquakes (LFEs) are small repeating earthquakes that occur in conjunction with deep slow slip. Like typical earthquakes, LFEs are thought to represent shear slip on crustal faults, but when compared to earthquakes of the same magnitude, LFEs are depleted in high-frequency content and have lower corner frequencies, implying longer duration. Here we exploit this difference to estimate the duration of LFEs on the deep San Andreas Fault (SAF). We find that the M ~ 1 LFEs have typical durations of ~0.2 s. Using the annual slip rate of the deep SAF and the average number of LFEs per year, we estimate average LFE slip rates of ~0.24 mm/s. When combined with the LFE magnitude, this number implies a stress drop of ~104 Pa, 2 to 3 orders of magnitude lower than ordinary earthquakes, and a rupture velocity of 0.7 km/s, 20% of the shear wave speed. Typical earthquakes are thought to have rupture velocities of ~80-90% of the shear wave speed. Together, the slow rupture velocity, low stress drops, and slow slip velocity explain why LFEs are depleted in high-frequency content relative to ordinary earthquakes and suggest that LFE sources represent areas capable of relatively higher slip speed in deep fault zones. Additionally, changes in rheology may not be required to explain both LFEs and slow slip; the same process that governs the slip speed during slow earthquakes may also limit the rupture velocity of LFEs. ©2016. American Geophysical Union. All Rights Reserved. URL: https://www.scopus.com/inward/record.uri?eid=2-s2.0-84959423028&doi=10.1002%2f2015GL067173&partnerID=40&md5=81126a5f93b14e9b90f7be0b1d0a3bf8
Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/10335
Appears in Collections: 科学计划与规划 气候变化与战略
There are no files associated with this item.
作者单位: Department of Geological Sciences, University of Oregon, Eugene, OR, United States
Recommended Citation:
Thomas A.M.,Beroza G.C.,Shelly D.R.. Constraints on the source parameters of low-frequency earthquakes on the San Andreas Fault[J]. Geophysical Research Letters,2016-01-01,43(4).