1. Faculty of Civil and Environmental Engineering, University of Tun Hussein Onn Malaysia, 86400 Parit Raja, Batu Pahat, Johor, Malaysia.
2. School of Civil Engineering, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.
3. School of Electronic, Electrical and Computer Engineering, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.
4. British Geological Survey, Keyworth, Nottingham, NG12 5GG, UK.