1. Institute of Earth Sciences, Academia Sinica, 128, Section 2, Academia Road, Nangang District, Taipei 11529, Taiwan, yenyulin@caltech.edu
2. Now at Seismological Laboratory, California Institute of Technology, 1200 East California Boulevard, MS 252‐21, Pasadena, California 91125.
3. Now at Department of Geological Sciences, San Diego State University, 5500 Campanile Drive, San Diego, California 92182.
4. Department of Earth Sciences, National Central University, No. 300, Jhongda Road, Jhongli District, Taoyuan 32001, Taiwan
5. Department of Earth Sciences, University College London, Gower Street, London WC1E 6BT, United Kingdom
6. Department of Geosciences, National Taiwan University, No. 1, Section 4, Roosevelt Road, Taipei 10617, Taiwan