Illuminating the physics of dynamic friction through laboratory earthquakes on thrust faults

Large, destructive earthquakes often propagate along thrust faults including megathrusts. The asymmetric interaction of thrust earthquake ruptures with the free surface leads to sudden variations in fault-normal stress, which affect fault friction. Here, we present full-field experimental measuremen...

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Bibliographic Details
Published inProceedings of the National Academy of Sciences - PNAS Vol. 117; no. 35; pp. 21095 - 21100
Main Authors Tal, Yuval, Rubino, Vito, Rosakis, Ares J., Lapusta, Nadia
Format Journal Article
LanguageEnglish
Published United States National Academy of Sciences 01.09.2020
Subjects
Earthquakes
Fault lines
Free surfaces
Friction
Friction resistance
Geological faults
Ground motion
Physical Sciences
Response time
Seismic activity
Shear strength
Stress
Thrust
dynamic friction
thrust faults
laboratory earthquakes
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Summary:Large, destructive earthquakes often propagate along thrust faults including megathrusts. The asymmetric interaction of thrust earthquake ruptures with the free surface leads to sudden variations in fault-normal stress, which affect fault friction. Here, we present full-field experimental measurements of displacements, particle velocities, and stresses that characterize the rupture interaction with the free surface, including the large normal stress reductions. We take advantage of these measurements to investigate the dependence of dynamic friction on transient changes in normal stress, demonstrate that the shear frictional resistance exhibits a significant lag in response to such normal stress variations, and identify a predictive frictional formulation that captures this effect. Properly accounting for this delay is important for simulations of fault slip, ground motion, and associated tsunami excitation.
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Reviewers: P.H.G., University of Illinois at Urbana–Champaign; and Y.H., Northwestern University.
Contributed by Ares J. Rosakis, April 15, 2020 (sent for review March 11, 2020; reviewed by Philippe H. Geubelle and Yonggang Huang)
Author contributions: Y.T., V.R., A.J.R., and N.L. designed research; Y.T., V.R., A.J.R., and N.L. performed research; Y.T. analyzed data; and Y.T., V.R., A.J.R., and N.L. wrote the paper.
ISSN:0027-8424
1091-6490
DOI:10.1073/pnas.2004590117