Electric potential changes associated with nucleation of stick-slip of simulated gouges

Kumi Onuma, Jun Muto, Hiroyuki Nagahama, Kenshiro Otsuki

Research output: Contribution to journalArticlepeer-review

18 Citations (Scopus)

Abstract

Our friction experiments using simulated gouges detected premonitory changes in electric potential before stick-slip events. These precursor electric signals have been detected both in piezoelectric quartz and non-piezoelectric gabbroic gouges. The changes in the potential were locally detected by electrodes set very close to the fault surface associated with slow slip prior to stick-slip events. The magnitude of electrification is proportional to fault slip associated with gradual stress releases, indicating that the electrification is slip-dependent process. From the detailed microstructural analyses on a representative sample, Riedel (R1) shears known to be formed during stable sliding were the most densely developed around the electrode pair which detected the precursory voltage changes. This indicates that local increases in the voltages were likely caused by frictional electrification due to slow slip on R1 shears in nucleation phases of stick-slip events. Our experimental results imply that natural faults with thicker gouge zones would require greater precursory slips, resulting in larger electric signals in the nucleation phase of earthquakes.

Original languageEnglish
Pages (from-to)308-314
Number of pages7
JournalTectonophysics
Volume502
Issue number3-4
DOIs
Publication statusPublished - 2011 Apr 20

Keywords

  • Electromagnetic signals
  • Friction experiment
  • Seismoelectromagnetic phenomena
  • Simulated gouges
  • Stick-slips

ASJC Scopus subject areas

  • Geophysics
  • Earth-Surface Processes

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