气候变化领域集成服务门户(CCPortal): Rheology of the Fluid Oversaturated Fault Zones at the Brittle-Plastic Transition

CCPortal

DOI	10.1029/2020JB020804
	Rheology of the Fluid Oversaturated Fault Zones at the Brittle-Plastic Transition
	Okazaki K.; Burdette E.; Hirth G.
发表日期	2021
ISSN	21699313
卷号	126 期号:2
英文摘要	Large earthquakes and slow slip events typically nucleate along plate boundaries near the depth limit of the seismogenic zone, which is also recognized as the brittle-plastic transition zone (BPT). High Vp/Vs ratios are commonly observed at the BPT in subduction zones, indicating the presence of aqueous fluid in pore spaces. We conducted experiments to investigate the rheology of quartz with different fluid fractions at deformation conditions that cross the BPT. The strengths of quartz aggregates with fluid-filled porosities of 5–25 vol% are significantly lower than predicted by wet quartzite flow laws, and decrease with increasing fluid fraction. Recovered samples deformed in the ductile regime exhibit S-C´ mylonitic structures characterized by elongate grains, shear localization and fluid segregation. Variations in strength are explained by a combination of a constitutive law for dislocation creep that includes the geometric effects of fluid fraction, a friction law that includes the effect of fluid fraction through its role on the real area of contact, and an empirical function to describe the smooth brittle-plastic transition. Our results indicate that the presence of fluid-filled porosity promotes significant weakening in shear zones, and that variations in fluid fraction (together with temperature) can explain transitions in the spectrum of slip behaviors observed along plate boundaries. © 2021. American Geophysical Union. All Rights Reserved.
英文关键词	brittle-plastic transition; earthquake; fluid; quartz; rheology; subduction zone
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/187389
作者单位	Kochi Institute for Core Sample Research, Japan Agency for Marine-Earth Science and Technology (Kochi, X-star, JAMSTEC), Nankoku, Kochi, Japan; Department of Earth, Environmental and Planetary Sciences, Brown University, Providence, RI, United States
推荐引用方式 GB/T 7714	Okazaki K.,Burdette E.,Hirth G.. Rheology of the Fluid Oversaturated Fault Zones at the Brittle-Plastic Transition[J],2021,126(2).
APA	Okazaki K.,Burdette E.,&Hirth G..(2021).Rheology of the Fluid Oversaturated Fault Zones at the Brittle-Plastic Transition.Journal of Geophysical Research: Solid Earth,126(2).
MLA	Okazaki K.,et al."Rheology of the Fluid Oversaturated Fault Zones at the Brittle-Plastic Transition".Journal of Geophysical Research: Solid Earth 126.2(2021).