On the evolution of elastic properties during laboratory stick-slip experiments spanning the transition from slow slip to dynamic rupture

E. Tinti, M. M. Scuderi, L. Scognamiglio, G. Di Stefano, C. Marone, C. Collettini

Research output: Contribution to journalArticlepeer-review

25 Scopus citations

Abstract

The physical mechanisms governing slow earthquakes remain unknown, as does the relationship between slow and regular earthquakes. To investigate the mechanism(s) of slow earthquakes and related quasi-dynamic modes of fault slip we performed laboratory experiments on simulated fault gouge in the double direct shear configuration. We reproduced the full spectrum of slip behavior, from slow to fast stick slip, by altering the elastic stiffness of the loading apparatus (k) to match the critical rheologic stiffness of fault gouge (kc). Our experiments show an evolution from stable sliding, when k > kc, to quasi-dynamic transients when k ~ kc, to dynamic instabilities when k < kc. To evaluate the microphysical processes of fault weakening we monitored variations of elastic properties. We find systematic changes in P wave velocity (Vp) for laboratory seismic cycles. During the coseismic stress drop, seismic velocity drops abruptly, consistent with observations on natural faults. In the preparatory phase preceding failure, we find that accelerated fault creep causes a Vp reduction for the complete spectrum of slip behaviors. Our results suggest that the mechanics of slow and fast ruptures share key features and that they can occur on same faults, depending on frictional properties. In agreement with seismic surveys on tectonic faults our data show that their state of stress can be monitored by Vp changes during the seismic cycle. The observed reduction in Vp during the earthquake preparatory phase suggests that if similar mechanisms are confirmed in nature high-resolution monitoring of fault zone properties may be a promising avenue for reliable detection of earthquake precursors.

Original languageEnglish (US)
Pages (from-to)8569-8594
Number of pages26
JournalJournal of Geophysical Research: Solid Earth
Volume121
Issue number12
DOIs
StatePublished - Dec 1 2016

All Science Journal Classification (ASJC) codes

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

Fingerprint Dive into the research topics of 'On the evolution of elastic properties during laboratory stick-slip experiments spanning the transition from slow slip to dynamic rupture'. Together they form a unique fingerprint.

Cite this