論文

査読有り
2018年5月9日

Strain rate effect on fault slip and rupture evolution: Insight from meter-scale rock friction experiments

Tectonophysics
  • Shiqing Xu
  • ,
  • Eiichi Fukuyama
  • ,
  • Futoshi Yamashita
  • ,
  • Kazuo Mizoguchi
  • ,
  • Shigeru Takizawa
  • ,
  • Hironori Kawakata

733
開始ページ
209
終了ページ
231
記述言語
英語
掲載種別
研究論文(学術雑誌)
DOI
10.1016/j.tecto.2017.11.039
出版者・発行元
Elsevier B.V.

We conduct meter-scale rock friction experiments to study strain rate effect on fault slip and rupture evolution. Two rock samples made of Indian metagabbro, with a nominal contact dimension of 1.5 m long and 0.1 m wide, are juxtaposed and loaded in a direct shear configuration to simulate the fault motion. A series of experimental tests, under constant loading rates ranging from 0.01 mm/s to 1 mm/s and under a fixed normal stress of 6.7 MPa, are performed to simulate conditions with changing strain rates. Load cells and displacement transducers are utilized to examine the macroscopic fault behavior, while high-density arrays of strain gauges close to the fault are used to investigate the local fault behavior. The observations show that the macroscopic peak strength, strength drop, and the rate of strength drop can increase with increasing loading rate. At the local scale, the observations reveal that slow loading rates favor generation of characteristic ruptures that always nucleate in the form of slow slip at about the same location. In contrast, fast loading rates can promote very abrupt rupture nucleation and along-strike scatter of hypocenter locations. At a given propagation distance, rupture speed tends to increase with increasing loading rate. We propose that a strain-rate-dependent fault fragmentation process can enhance the efficiency of fault healing during the stick period, which together with healing time controls the recovery of fault strength. In addition, a strain-rate-dependent weakening mechanism can be activated during the slip period, which together with strain energy selects the modes of fault slip and rupture propagation. The results help to understand the spectrum of fault slip and rock deformation modes in nature, and emphasize the role of heterogeneity in tuning fault behavior under different strain rates.

リンク情報
DOI
https://doi.org/10.1016/j.tecto.2017.11.039
ID情報
  • DOI : 10.1016/j.tecto.2017.11.039
  • ISSN : 0040-1951
  • SCOPUS ID : 85039421094

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