1. Department of Civil Engineering, Kaohsiung Polytechnic Institute, Ta-Hsu Hsiang, Kaohsiung County, Taiwan 84008, Republic of China
2. Department of Civil & Environmental Engineering, University of Delaware, Newark, Delaware 19716
3. Department of Geology, University of Delaware, Newark, Delaware 19716
4. Division of Science & Research, New Jersey Department of Environmental Protection and Energy, Trenton, New Jersey 08625