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Photo-acoustic study of subshear and supershear ruptures in the laboratory
Author(s)
Language
English
Obiettivo Specifico
3.1. Fisica dei terremoti
Status
Published
JCR Journal
JCR Journal
Peer review journal
Yes
Title of the book
Issue/vol(year)
3-4/308 (2011)
Publisher
Elsevier
Pages (printed)
424–432
Issued date
August 15, 2011
Abstract
We report supershear ruptures observed in spontaneously nucleating laboratory microearthquakes and describe the signature of the associated Mach wavefront radiation. Transducers detect the wavefield both close and at a distance from the fault. The rupture velocities are inferred from either photoelastic high-speed imaging or using the acoustic recordings; both methods yield compatible estimates of sufficient accuracy to discriminate between sub-shear and supershear ruptures. The acoustic records allow to characterize the Mach wavefront radiated from the supershear rupture front, in particular its amplitude and decay. Velocity functions recovered by integrating high frequency accelerometer signals in the case of supershear ruptures, consist in a double-pulse function: a first pulse traveling at supershear velocity followed by a second pulse traveling at the Rayleigh wave velocity. Conversely, the sub-shear event is characterized by a single pulse. Finally, we perform numerical simulations of our experiment using a prescribed supershear rupture velocity. The synthetic waveforms obtained from these simulations, including the Mach wave amplitude and phase, yield a satisfactory fit to the experimental results. (C) 2011 Elsevier B.V. All rights reserved.
Sponsors
European Research Council (USEMS), AMRA, TRIGS
Type
article
File(s)
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Name
SchubnelEPSL2011.pdf
Description
main paper
Size
1.48 MB
Format
Adobe PDF
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