HR: 1330h
AN: S22A-0431    [PDF]
TI: Experimental Study of the Failure Procedure of Echelon Fault Structure Using Digital Speckle Correlation Method (DSCM)
AU: * Ma, S
EM: masp@pku.edu.cn
AF: Dept of Geophysics, Peking University, Beijing, 100871 China
AU: * Ma, S
EM: masp@pku.edu.cn
AF: Dept of Engineering Mechanics, Tsinghua University, Beijing, 100084 China
AU: Liu, S
EM: Liusj@263.net
AF: Dept of Mining Eng \& Surveying, China University of Mining \& Technology, Beijing, 100083 China
AU: Zhao, Y
EM: Zhaoyh@pku.edu.cn
AF: Dept of Geophysics, Peking University, Beijing, 100871 China
AB: The echelon fault structure is one of the most important structures in the earth's crust because it often initializes earthquakes. Therefore, the mechanism for the failure of this fault structure is of great importance to the understanding of earthquakes. In this study, the failure procedure of echelon fault structures are experimentally studied using digital speckle correlation method (DSCM). The specimen is a marble plate 400 mm x 400 mm x 40 mm in size. In order to simulate the echelon fault structure, 2 parallel slits are cut and then filled with gypsum. The specimens are loaded on a 500 T large scale double-axis test machine. During the experiment, the specimen is loaded laterally with a pressure of 40 MPa first and then compressed axially under the constant displacement rate of 0.02 mm/min. The DSCM system captures speckle images during the test process at 1 frame/sec. About 900 images were captured during the 15 minute compression test for each sample. 4 samples are tested with the same structure and loading in this experiment. The whole failure procedure of echelon fault structure and the field deformation on the surface of the sample was revealed by DSCM system. It is clearly shown by the evolution of the deformation field that the deformation is firstly localized at the fault zones and then the echelon area, where the two faults are interactive with each other. The failure also finally evolved in this echelon area. Based on these experimental results, a detailed failure procedure and the mechanism of failure were analyzed. Moreover, the deformation field during loading is statistically studied and a quantitative Cv-value, which expresses the characteristics of deformation localization, is an indicator for the failure of the echelon fault structure.
DE: 5104 Fracture and flow
DE: 5194 Instruments and techniques
DE: 7209 Earthquake dynamics and mechanics
DE: 7218 Lithosphere and upper mantle
SC: Seismology [S]
MN: 2003 Fall Meeting