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International Journal of Geophysics
Volume 2012 (2012), Article ID 142069, 10 pages
http://dx.doi.org/10.1155/2012/142069
Research Article

Experimental Studies on the Changes in Resistivity and Its Anisotropy Using Electrical Resistivity Tomography

Institute of Geophysics, China Earthquake Administration, Beijing 100081, China

Received 10 March 2011; Revised 10 July 2011; Accepted 8 August 2011

Academic Editor: Sabatino Piscitelli

Copyright © 2012 Tao Zhu et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Three measuring lines were arranged on one of free planes of magnetite cuboid samples. Apparent resistivity data were acquired by MIR-2007 resistivity meter when samples were under uniaxial compression of servocontrol YAW-5000F loadingmachine in laboratory. Then we constructed the residual resistivity images using electrical resistivity tomography (ERT) and plotted the diagrams of apparent resistivity anisotropy coefficient (ARAC) and the included angle α between the major axis of apparent resistivity anisotropy ellipse and the axis of load with pressure and effective depth. Our results show that with increasing pressure, resistivity and the decreased (D region) and increased (I region) resistivity regions have complex behaviors, but when pressure is higher than a certain value, the average resistivity decrease and the area of D region expand gradually in all time with the increase of pressure, which may be significant to the monitoring and prediction of earthquake, volcanic activities, and large-scale geologic motions. The effects of pressure on and α are not very outstanding for dry magnetite samples.