1. Ph.D. Student, School of Engineering, Newcastle Univ., Newcastle upon Tyne NE1 7RU, UK.
2. Reader in Computational Geomechanics, School of Engineering, Newcastle Univ., Newcastle upon Tyne NE1 7RU, UK (corresponding author).
3. Professor of Earth Systems, School of Engineering, Newcastle Univ., Newcastle upon Tyne NE1 7RU, UK.