1. Institute for Geophysics, Jackson School of Geosciences; University of Texas; Austin Texas USA
2. Now at Center for Earthquake Research and Information; University of Memphis; Memphis Tennessee USA
3. Institute of Earth Sciences; Academia Sinica; Taipei Taiwan
4. Department of Geological Sciences, Jackson School of Geosciences; University of Texas; Austin Texas USA
5. King Abdullah University of Science and Technology (KAUST), Center for Numerical Porous Media, Applied Mathematics & Computational Science, and Earth Science & Engineering; Thuwal Saudi Arabia