A rotary-shear low to high-velocity friction apparatus in Beijing to study rock friction at plate to seismic slip rates
Shengli Ma1, Toshihiko Shimamoto1, Lu Yao1, Tetsuhiro Togo1,2, Hiroko Kitajima2,3
1 State Key Laboratory of Earthquake Dynamics, Institute of Geology, China Earthquake Administration, Beijing 100029, China 2 Institute of Earthquake and Volcano Geology, Advanced Institute for Industrial Science and Technology (AIST), Tsukuba Central 7, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8567, Japan Department of Geology and Geophysics, Center for Department of Geology and Geophysics, Center for Tectonophysics, Texas A&M University, College Station, TX 77843, USA
A rotary-shear low to high-velocity friction apparatus in Beijing to study rock friction at plate to seismic slip rates
Shengli Ma1, Toshihiko Shimamoto1, Lu Yao1, Tetsuhiro Togo1,2, Hiroko Kitajima2,3
1 State Key Laboratory of Earthquake Dynamics, Institute of Geology, China Earthquake Administration, Beijing 100029, China 2 Institute of Earthquake and Volcano Geology, Advanced Institute for Industrial Science and Technology (AIST), Tsukuba Central 7, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8567, Japan 3 Department of Geology and Geophysics, Center for Tectonophysics, Texas A&M University, College Station, TX 77843, USA
摘要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 103 or 106 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 500 _C. Velocity step tests are needed to see if the framework of rate-and-state friction is applicable or not at high velocities. We report results from velocity jump tests from 1.4 mm/s to 1.4 m/s on yellowish gouge from a Pingxi fault zone, located at the northeastern part of the Longmenshan fault system that caused the 2008 Wenchuan earthquake. An instantaneous increase in friction followed by dramatic slip weakening was observed for the yellowish gouge with smooth sliding surfaces of host rock, but no instantaneous response was recognized for the same gouge with roughened sliding surfaces. Instantaneous and transient frictional properties upon velocity steps cannot be separated easily at high velocities, and technical improvements for velocity step tests are suggested.
Abstract：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 103 or 106 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 500 _C. Velocity step tests are needed to see if the framework of rate-and-state friction is applicable or not at high velocities. We report results from velocity jump tests from 1.4 mm/s to 1.4 m/s on yellowish gouge from a Pingxi fault zone, located at the northeastern part of the Longmenshan fault system that caused the 2008 Wenchuan earthquake. An instantaneous increase in friction followed by dramatic slip weakening was observed for the yellowish gouge with smooth sliding surfaces of host rock, but no instantaneous response was recognized for the same gouge with roughened sliding surfaces. Instantaneous and transient frictional properties upon velocity steps cannot be separated easily at high velocities, and technical improvements for velocity step tests are suggested.
Shengli Ma, Toshihiko Shimamoto, Lu Yao, Tetsuhiro Togo, Hiroko Kitajima. A rotary-shear low to high-velocity friction apparatus in Beijing to study rock friction at plate to seismic slip rates[J]. 《地震学报》英文版, 2014, 27(5): 469-497.
Shengli Ma, Toshihiko Shimamoto, Lu Yao, Tetsuhiro Togo, Hiroko Kitajima. A rotary-shear low to high-velocity friction apparatus in Beijing to study rock friction at plate to seismic slip rates. Earthquake Science, 2014, 27(5): 469-497.
