Probing the slip‐weakening mechanism of earthquakes with electrical conductivity: Rapid transition from asperity contact to gouge comminution

Yamashita, Futoshi; Fukuyama, Eiichi; Mizoguchi, Kazuo

doi:10.1002/2013gl058671

Cited by 13 publications

(16 citation statements)

References 29 publications

(54 reference statements)

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“…In contrast, the transmitted wave amplitudes are related to the distribution of voids that become scatterers of the elastic waves. Therefore, the observations by Yamashita et al (2014) are complementary to those in the present study. At this moment, unfortunately, we could not measure the transmitted waves and electric conductivity simultaneously in the same experiment because of the electric isolation issue.…”

Section: Discussionsupporting

confidence: 81%

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Voids and Rock Friction at Subseismic Slip Velocity

Fukuyama

Yamashita

Mizoguchi

2017

Pure Appl. Geophys.

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Abstract-We found that the amplitudes of transmitted waves across the sliding surfaces are inversely correlated to high slip rate friction, especially when the interfaces slide fast ([ 10 -3 m/s). During the rock-rock friction experiments of metagabbro and diorite at sub-seismic slip rate (* 10 -3 m/s), friction does not reach steady state but fluctuates within certain range. The amplitudes of compressional waves transmitted across the slipping interfaces decrease when sliding friction becomes high and it increases when friction is low. Such amplitude variation can be interpreted based on the scattering theory; small amplitudes in transmitted waves correspond to the creation of large-scale (* 50 lm) voids and large amplitudes correspond to the smallscale (* 0.5 lm) voids. Thus, large-scale voids could be generated during the high-friction state and low-friction state was achieved by grain size reduction caused by a comminution process. This was partly confirmed by the experiments with a synthetic gouge layer. The result can be interpreted as an extension of force chain theory to high-velocity sliding regime; force chains were built during the high friction and they were destroyed during the low friction. This mechanism could be a microscopic aspect of friction evolution at sub-seismic slip rate.

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Section: Discussionsupporting

confidence: 81%

“…Recently, Yamashita et al (2014) measured electric conductivity across the sliding interface during high slip velocity friction experiments. They showed apparent temporal correlation between conductivity and friction coefficient during the experiment.…”

Section: Discussionmentioning

confidence: 99%

Voids and Rock Friction at Subseismic Slip Velocity

Fukuyama

Yamashita

Mizoguchi

2017

Pure Appl. Geophys.

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“…The melt patches as small as ~5 µm might be the product of flash heating at elevated temperatures (Figures c and S4), and the larger ones (~100–200 µm in size) might have formed by the growth of smaller ones. The melt patch formation and growth appear to be correlated with fault strengthening (Figure ) [ Hirose and Shimamoto , ; Kim et al ., ; Otsuki et al ., ; Yamashita et al ., ]. Further bulk temperature increases during the strengthening may lead to the formation of a melt layer (Figure e) and, consequently, fault weakening (or melt lubrication) [e.g., Hirose and Shimamoto , ; Nielsen et al ., ].…”

Section: Discussionmentioning

confidence: 99%

Frictional melting of clayey gouge during seismic fault slip: Experimental observation and implications

Han

Hirose

Jeong

et al. 2014

Geophysical Research Letters

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Clayey gouges are common in fault slip zones at shallow depths. Thus, the fault zone processes and frictional behaviors of the gouges are critical to understanding seismic slip at these depths. We conducted rotary shear tests on clayey gouge (~41 wt % clay minerals) at a seismic slip rate of 1.3 m/s. Here we report that the gouge was melted at 5 MPa of normal stress and room humidity conditions. The initial local melting was followed by melt layer formation. Clay minerals (e.g., smectite and illite) and plagioclase were melted and quenched to glass with numerous vesicles. Both flash heating and bulk temperature increases appear to be responsible for the melting. This observation of clayey gouge melting is comparable to that of natural faults (e.g., Chelungpu fault, Taiwan). Due to heterogeneous fault zone properties (e.g., permeability), frictional melting may be one of the important processes in clayey slip zones at shallow depths.

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“…Such instabilities are often observed in laboratory experiments [1][2][3][4][5][6][7][8][9]. At much larger scales, these instabilities may explain how aftershocks can be triggered by acoustic waves from earthquakes elsewhere [10][11][12][13][14][15].…”

Section: Introductionmentioning

confidence: 90%

Stick-slip instabilities in sheared granular flow: The role of friction and acoustic vibrations

et al. 2015

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We propose a theory of shear flow in dense granular materials. A key ingredient of the theory is an effective temperature that determines how the material responds to external driving forces such as shear stresses and vibrations. We show that, within our model, friction between grains produces stick-slip behavior at intermediate shear rates, even if the material is rate-strengthening at larger rates. In addition, externally generated acoustic vibrations alter the stick-slip amplitude, or suppress stick-slip altogether, depending on the pressure and shear rate. We construct a phase diagram that indicates the parameter regimes for which stick-slip occurs in the presence and absence of acoustic vibrations of a fixed amplitude and frequency. These results connect the microscopic physics to macroscopic dynamics, and thus produce useful information about a variety of granular phenomena including rupture and slip along earthquake faults, the remote triggering of instabilities, and the control of friction in material processing.

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Probing the slip‐weakening mechanism of earthquakes with electrical conductivity: Rapid transition from asperity contact to gouge comminution

Cited by 13 publications

References 29 publications

Voids and Rock Friction at Subseismic Slip Velocity

Voids and Rock Friction at Subseismic Slip Velocity

Frictional melting of clayey gouge during seismic fault slip: Experimental observation and implications

Stick-slip instabilities in sheared granular flow: The role of friction and acoustic vibrations

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