Evolution of b-value during the seismic cycle: Insights from laboratory experiments on simulated faults

J. Rivière, Z. Lv, P. A. Johnson, C. Marone

Research output: Contribution to journalArticle

24 Citations (Scopus)

Abstract

We investigate the evolution of the frequency-magnitude b-value during stable and unstable frictional sliding experiments. Using a biaxial shear configuration, we record broadband acoustic emissions (AE) while shearing layers of simulated granular fault gouge under normal stresses of 2–8 MPa and shearing velocity of 11 μm/s. AE event amplitude ranges over 3–4 orders of magnitude and we find an inverse correlation between b and shear stress. The reduction of b occurs systematically as shear stress rises prior to stick–slip failure and indicates a greater proportion of large events when faults are more highly stressed. For quasi-periodic stick–slip events, the temporal evolution of b has a characteristic saw-tooth pattern: it slowly drops as shear stress increases and quickly jumps back up at the time of failure. The rate of decrease during the inter-seismic period is independent of normal stress but the average value of b decreases systematically with normal stress. For stable sliding, b is roughly constant during shear, however it exhibits large variability. During irregular stick–slip, we see a mix of both behaviors: b decreases during the interseismic period between events and then remains constant when shear stress stabilizes, until the next event where a co-seismic increase is observed. Our results will help improve seismic hazard assessment and, ultimately, could aid earthquake prediction efforts by providing a process-based understanding of temporal changes in b-value during the seismic cycle.

Original languageEnglish (US)
Pages (from-to)407-413
Number of pages7
JournalEarth and Planetary Science Letters
Volume482
DOIs
StatePublished - Jan 15 2018

Fingerprint

shear stress
Shear stress
cycles
acoustic emission
Acoustic emissions
Shearing
sliding
shearing
Experiments
fault gouge
earthquake prediction
shear
hazard assessment
temporal evolution
seismic hazard
tooth
Earthquakes
teeth
Hazards
hazards

All Science Journal Classification (ASJC) codes

  • Geophysics
  • Geochemistry and Petrology
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science

Cite this

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title = "Evolution of b-value during the seismic cycle: Insights from laboratory experiments on simulated faults",
abstract = "We investigate the evolution of the frequency-magnitude b-value during stable and unstable frictional sliding experiments. Using a biaxial shear configuration, we record broadband acoustic emissions (AE) while shearing layers of simulated granular fault gouge under normal stresses of 2–8 MPa and shearing velocity of 11 μm/s. AE event amplitude ranges over 3–4 orders of magnitude and we find an inverse correlation between b and shear stress. The reduction of b occurs systematically as shear stress rises prior to stick–slip failure and indicates a greater proportion of large events when faults are more highly stressed. For quasi-periodic stick–slip events, the temporal evolution of b has a characteristic saw-tooth pattern: it slowly drops as shear stress increases and quickly jumps back up at the time of failure. The rate of decrease during the inter-seismic period is independent of normal stress but the average value of b decreases systematically with normal stress. For stable sliding, b is roughly constant during shear, however it exhibits large variability. During irregular stick–slip, we see a mix of both behaviors: b decreases during the interseismic period between events and then remains constant when shear stress stabilizes, until the next event where a co-seismic increase is observed. Our results will help improve seismic hazard assessment and, ultimately, could aid earthquake prediction efforts by providing a process-based understanding of temporal changes in b-value during the seismic cycle.",
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Evolution of b-value during the seismic cycle : Insights from laboratory experiments on simulated faults. / Rivière, J.; Lv, Z.; Johnson, P. A.; Marone, C.

In: Earth and Planetary Science Letters, Vol. 482, 15.01.2018, p. 407-413.

Research output: Contribution to journalArticle

TY - JOUR

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