气候变化领域集成服务门户(CCPortal): Precursory Slow Slip and Foreshocks on Rough Faults

CCPortal

DOI	10.1029/2020JB020430
	Precursory Slow Slip and Foreshocks on Rough Faults
	Cattania C.; Segall P.
发表日期	2021
ISSN	21699313
卷号	126 期号:4
英文摘要	Foreshocks are not uncommon prior to large earthquakes, but their physical mechanism remains controversial. Two interpretations have been advanced: (1) foreshocks are driven by aseismic nucleation and (2) foreshocks are cascades, with each event triggered by earlier ones. Here, we study seismic cycles on faults with fractal roughness at wavelengths exceeding the nucleation length. We perform 2-D quasi-dynamic, elastic simulations of frictionally uniform rate-state faults. Roughness leads to a range of slip behavior between system-size ruptures, including widespread creep, localized slow slip, and microseismicity. These processes are explained by spatial variations in normal stress (σ) caused by roughness: regions with low σ tend to creep, while high σ regions remain locked until they break seismically. Foreshocks and mainshocks both initiate from the rupture of locked asperities, but mainshocks preferentially start on stronger asperities. The preseismic phase is characterized by feedback between creep and foreshocks: episodic seismic bursts break groups of nearby asperities, causing creep to accelerate, which in turns loads other asperities leading to further foreshocks. A simple analytical treatment of this mutual stress transfer, confirmed by simulations, predicts slip velocities and seismicity rates increase as 1/t, where t is the time to the mainshock. The model reproduces the observed migration of foreshocks toward the mainshock hypocenter, foreshock locations consistent with static stress changes, and the 1/t acceleration in stacked catalogs. Instead of interpreting foreshocks as either driven by coseismic stress changes or by creep, we propose that earthquake nucleation on rough faults is driven by the feedback between the two. © 2021. American Geophysical Union. All Rights Reserved.
英文关键词	earthquake nucleation; fault roughness; foreshocks
语种	英语
来源期刊	Journal of Geophysical Research: Solid Earth
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/187245
作者单位	Department of Geophysics, Stanford University, Stanford, CA, United States; Now at Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA, United States
推荐引用方式 GB/T 7714	Cattania C.,Segall P.. Precursory Slow Slip and Foreshocks on Rough Faults[J],2021,126(4).
APA	Cattania C.,&Segall P..(2021).Precursory Slow Slip and Foreshocks on Rough Faults.Journal of Geophysical Research: Solid Earth,126(4).
MLA	Cattania C.,et al."Precursory Slow Slip and Foreshocks on Rough Faults".Journal of Geophysical Research: Solid Earth 126.4(2021).