1. Rock Mechanics Group, Amirkabir University of Technology, Tehran, 1591634311 Iran
2. Western Australian School of Mines (WASM), Curtin University, 6907 Australia
3. Rock Mechanics Group, Tarbiat Modares University, Tehran, 14117-13116 Iran
4. Physics Department, Shiraz University, Shiraz, 71964-84334 Iran