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Tectonic tremor as friction-induced inertial vibration

Im, Kyungjae and Avouac, Jean-Philippe (2021) Tectonic tremor as friction-induced inertial vibration. Earth and Planetary Science Letters, 576 . Art. No. 117238. ISSN 0012-821X. doi:10.1016/j.epsl.2021.117238.

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Slow slip events are often accompanied by tremor but how tremor is generated is yet elusive. In this study, we test the possibility that it is an inertial vibration. In the case of a single-degree-of-freedom spring and slider system with mass per unit area M, governed by rate-and-state friction with effective normal stress σ′, excitation of inertial vibrations emerges when normal stress (σ′) is low, and loading rate (V_l) is high. Accordingly, tremor can be excited in a low effective normal stress (σ′) zone, for example, in a zone of high pore pressure, when the loading rate (V_l) is temporally increased, as can happen during a slow slip event. A high loading rate helps to sustain the vibration, but a long-lasting attenuating tremor can still be excited even with a moderate velocity perturbation as long as the normal stress is sufficiently small. We use numerical simulations to verify that this hypothesis holds for a one-dimensional fault. The dominant frequency of the tremor is close to the fundamental frequency of resonance of the frictionless shear crack at a low sliding rate. Higher frequency modes are excited at higher sliding velocity. We show simulations of spontaneous slow slip events associated with tremor radiated from inertial vibration of a fault patch with locally low effective normal stress. This model provides a possible explanation for tectonic tremor associated with slow slip events.

Item Type:Article
Related URLs:
URLURL TypeDescription
Im, Kyungjae0000-0003-0057-3119
Avouac, Jean-Philippe0000-0002-3060-8442
Additional Information:© 2021 Elsevier B.V. Received 18 December 2020, Revised 16 September 2021, Accepted 1 October 2021, Available online 14 October 2021. We thank two anonymous reviewers for their insightful and constructive evaluations and Jean-Paul Ampuero for valuable discussions. This study was supported by NSF EAR-1821853. CRediT authorship contribution statement: Kyungjae Im: Conceptualization, Methodology, Software, Writing – original draft. Jean-Philippe Avouac: Conceptualization, Validation, Writing – review & editing. The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Group:Center for Geomechanics and Mitigation of Geohazards (GMG), Division of Geological and Planetary Sciences, Seismological Laboratory
Funding AgencyGrant Number
Subject Keywords:tremor; slow slip; low frequency earthquake; rate and state friction; inertial vibration
Record Number:CaltechAUTHORS:20211025-190753665
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Official Citation:Kyungjae Im, Jean-Philippe Avouac, Tectonic tremor as friction-induced inertial vibration, Earth and Planetary Science Letters, Volume 576, 2021, 117238, ISSN 0012-821X,
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:111638
Deposited By: Tony Diaz
Deposited On:26 Oct 2021 17:29
Last Modified:15 Nov 2022 19:10

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