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DOI	10.1073/pnas.2101469118
	Repeating caldera collapse events constrain fault friction at the kilometer scale
	Segall P.; Anderson K.
发表日期	2021
ISSN	0027-8424
卷号	118 期号:30
英文摘要	Fault friction is central to understanding earthquakes, yet laboratory rock mechanics experiments are restricted to, at most, meter scale. Questions thus remain as to the applicability of measured frictional properties to faulting in situ. In particular, the slip-weakening distance dc strongly influences precursory slip during earthquake nucleation, but scales with fault roughness and is challenging to extrapolate to nature. The 2018 eruption of K¯ılauea volcano, Hawaii, caused 62 repeatable collapse events in which the summit caldera dropped several meters, accompanied by MW 4.7 to 5.4 very long period (VLP) earthquakes. Collapses were exceptionally well recorded by global positioning system (GPS) and tilt instruments and represent unique natural kilometer-scale friction experiments. We model a piston collapsing into a magma reservoir. Pressure at the piston base and shear stress on its margin, governed by rate and state friction, balance its weight. Downward motion of the piston compresses the underlying magma, driving flow to the eruption. Monte Carlo estimation of unknowns validates laboratory friction parameters at the kilometer scale, including the magnitude of steady-state velocity weakening. The absence of accelerating precollapse deformation constrains dc to be ≤10 mm, potentially much less. These results support the use of laboratory friction laws and parameters for modeling earthquakes. We identify initial conditions and material and magma-system parameters that lead to episodic caldera collapse, revealing that small differences in eruptive vent elevation can lead to major differences in eruption volume and duration. Most historical basaltic caldera collapses were, at least partly, episodic, implying that the conditions for stick–slip derived here are commonly met in nature. © 2021 National Academy of Sciences. All rights reserved.
英文关键词	Caldera collapse; Fault friction; Kılauea volcano
语种	英语
来源期刊	Proceedings of the National Academy of Sciences of the United States of America
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/238849
作者单位	Geophysics Department, Stanford University, Stanford, CA 94305, United States; US Geological Survey, Volcano Science Center, Moffett Field, CA 94035, United States
推荐引用方式 GB/T 7714	Segall P.,Anderson K.. Repeating caldera collapse events constrain fault friction at the kilometer scale[J],2021,118(30).
APA	Segall P.,&Anderson K..(2021).Repeating caldera collapse events constrain fault friction at the kilometer scale.Proceedings of the National Academy of Sciences of the United States of America,118(30).
MLA	Segall P.,et al."Repeating caldera collapse events constrain fault friction at the kilometer scale".Proceedings of the National Academy of Sciences of the United States of America 118.30(2021).