Structures and high-velocity frictional properties of the Pingxi fault zone in the Longmenshan fault system, Sichuan, China, activated during the 2008 Wenchuan earthquake

Yao, Lu; Ma, Shuping; Shimamoto, Toshihiko; Togo, Tetsuhiro

doi:10.1016/j.tecto.2013.04.011

Cited by 59 publications

(122 citation statements)

References 56 publications

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“…The U layers consisted of ultrafine grains that were mostly less than 1 μm in diameter and appeared to be welded or sintered. Similar textures were reported previously (Sawai et al, 2012;Togo and Shimamoto, 2012;Yao et al, 2013aYao et al, , 2013b. These highly deformed zones consisting of ultrafine grains may be slip zones in which the shear deformation was concentrated.…”

Section: Microstructural Observationssupporting

confidence: 86%

“…Single or overlapping stratified structures of the U layer, CCA-bearing layers, and CCA-free layers were observed in air-dried samples and wet samples after large shear displacements (Boutareaud et al, 2010;Ferri et al, 2011;Han and Hirose, 2012;Sawai et al, 2012;Yao et al, 2013aYao et al, , 2013b. In conclusion, the microstructures of our sheared semi-wet fault gouges are similar to those of the dry samples.…”

Section: Microstructures Of Deformed Gougesupporting

confidence: 58%

“…Based on rotary shear tests of dry fault gouge samples, Yao et al (2013a) reported that a fine-grained deformation zone forms in the upper part of the fault gouge layer near the rotational side of the host rock with a slip displacement of 0.13 m at a normal stress of 2.5 MPa and a slip rate of 0.0014 m/s. Single or overlapping stratified structures of the U layer, CCA-bearing layers, and CCA-free layers were observed in air-dried samples and wet samples after large shear displacements (Boutareaud et al, 2010;Ferri et al, 2011;Han and Hirose, 2012;Sawai et al, 2012;Yao et al, 2013aYao et al, , 2013b.…”

Section: Microstructures Of Deformed Gougementioning

confidence: 99%

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Initiation, movement, and run-out of the giant Tsaoling landslide — What can we learn from a simple rigid block model and a velocity–displacement dependent friction law?

Yang

Dong

et al. 2014

Engineering Geology

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Tsaoling landslide is the largest and best documented landslide among several large landslides induced by the 1999 Taiwan Chi-Chi earthquake. Pliocene sedimentary rocks of about 125 Mm 3 in volume slid along very flat bedding planes dipping by 14°with an average speed of 35-40 m/s for about 1650 m, before hitting the bank of the Chinshui River during the landslide. Detailed analysis of DTMs before and after the earthquake using a GIS software leads to an accurate determination of the locations of the centroids of landslide mass, revealing the horizontal and vertical displacements of the 2524 m and 524 m, respectively. Those displacements and landslide mass give an apparent friction coefficient of 0.21 and the release of the potential energy of 1.6 × 10 15 J. We conducted rotary-shear high-velocity friction experiments on fault gouge from bedding-parallel faults under semi-wet conditions and at 3 MPa normal stress corresponding to the overburden pressure of the landslide mass. We also compiled reported data on the frictional properties on shale powders and fault gouge from the landslide site under both dry and wet conditions, and proposed a velocity-displacement dependent friction law that can describe most experimental data. Newmark analysis of landslide motion with six scenarios for different landslide materials and conditions, assuming a simple rigid block sliding and using measured frictional parameters, revealed that the landslide did not occur with dry frictional properties, and that the landslide occurred at 38-39 s with accumulated displacements of 0.62 m-1.09 m and reached at the river bank at 82-87 s after the generation of Chi-Chi earthquake at its epicenter. Those timings are consistent with highfrequency signals at 32-40 s and at 76 s recorded at a nearby seismic station and with a survivor's witness that the landslide initiated 10 s after he felt strong ground motion, possible S wave arrival at 25.2 s. Slipweakening is essential in initiating the landslide and low friction coefficient (0.08-0.1) allowed high-speed of the landslide possible. The landslide was caused by a few peaks of northeast-oriented strong accelerations of the ground motion. Frictional work during the sliding of the landslide mass was estimated to be of about 23% of potential energy, and the rest of the released energy is likely to have been consumed during the stopping phase of the landslide after hitting the river bank in complex processes such as fragmentation, heat dissipation, and spreading of the landslide deposits.

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Section: Microstructural Observationssupporting

confidence: 86%

Section: Microstructures Of Deformed Gougesupporting

confidence: 58%

Section: Microstructures Of Deformed Gougementioning

confidence: 99%

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Initiation, movement, and run-out of the giant Tsaoling landslide — What can we learn from a simple rigid block model and a velocity–displacement dependent friction law?

Yang

Dong

et al. 2014

Engineering Geology

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“…We record outputs from torque gauge, axial force gauge, axial displacement transducer, rotary encoder, and potentiometer in Kyowa Universal Recorder EDX-100A with a sampling frequency up to 10 kHz for 8 channels. We record data mostly with 1 kHz sampling rate and analyze them following the procedures described in Yao et al (2013a).…”

Section: Constitution Of the Apparatusmentioning

confidence: 99%

“…YG is one of the beststudied gouges from the Longmenshan fault system, Sichuan province, China, after the earthquake (see Yao et al 2013a;Chen et al 2013a, c) for the description of the fault-zone structures at this outcrop and the gouge used in experiments). YG is composed of calcite (59 %), quartz (21 %), dolomite (11 %), illite (5 %), barite (3 %), and other subsidiary minerals, with a grain size of 8.0 lm at a frequency of 50 vol% Fig.…”

Section: Velocity-jump Tests On Pingxi Fault Gougementioning

confidence: 99%

A rotary-shear low to high-velocity friction apparatus in Beijing to study rock friction at plate to seismic slip rates

Shimamoto

Yao

et al. 2014

Earthq Sci

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This paper reviews 19 apparatuses having highvelocity capabilities, describes a rotary-shear low to highvelocity friction apparatus installed at Institute of Geology, China Earthquake Administration, and reports results from velocity-jump tests on Pingxi fault gouge to illustrate technical problems in conducting velocity-stepping tests at high velocities. The apparatus is capable of producing plate to seismic velocities (44 mm/a to 2.1 m/s for specimens of 40 mm in diameter), using a 22 kW servomotor with a gear/belt system having three velocity ranges. A speed range can be changed by 10 3 or 10 6 by using five electromagnetic clutches without stopping the motor. Two cam clutches allow fivefold velocity steps, and the motor speed can be increased from zero to 1,500 rpm in 0.1-0.2 s by changing the controlling voltage. A unique feature of the apparatus is a large specimen chamber where different specimen assemblies can be installed easily. In addition to a standard specimen assembly for friction experiments, two pressure vessels were made for pore pressures to 70 MPa; one at room temperature and the other at temperatures to

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Triggering and runaway processes of catastrophic Tsaoling landslide induced by the 1999 Taiwan Chi-Chi earthquake, as revealed by high-velocity friction experiments

Togo

Shimamoto

Dong

et al. 2014

Geophys. Res. Lett.

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Pliocene sedimentary rocks of about 130 Mm 3 in volume slid along bedding planes dipping by 14°, with an average speed of about 35 m/s, during the Tsaoling landslide. We conducted friction experiments to reproduce the initiation processes of this landslide, by idealizing landslide movements during the earthquake as accelerating/decelerating motion. Experiments were done on shale from the field, at 3 MPa normal stress corresponding to the overburden pressure. Results indicate that the accelerating/decelerating motion causes weakening and strengthening at each oscillation cycle and results in overall slip weakening which can be approximated as an exponential slip weakening. Behaviors during oscillatory slip are fairly similar to those during sliding at constant slip rates. Newmark analysis with measured frictional properties reveals that the landslide can be triggered with wet gouge properties, but the landslide motion stops with parameters for dry shale gouge. Delayed initiation of the landslide is consistent with a survivor's witness.

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Structures and high-velocity frictional properties of the Pingxi fault zone in the Longmenshan fault system, Sichuan, China, activated during the 2008 Wenchuan earthquake

Cited by 59 publications

References 56 publications

Initiation, movement, and run-out of the giant Tsaoling landslide — What can we learn from a simple rigid block model and a velocity–displacement dependent friction law?

Initiation, movement, and run-out of the giant Tsaoling landslide — What can we learn from a simple rigid block model and a velocity–displacement dependent friction law?

A rotary-shear low to high-velocity friction apparatus in Beijing to study rock friction at plate to seismic slip rates

Triggering and runaway processes of catastrophic Tsaoling landslide induced by the 1999 Taiwan Chi-Chi earthquake, as revealed by high-velocity friction experiments

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