1. Department of Earth and Space Sciences; University of Washington; Seattle Washington USA
2. Department of Geological Sciences; University of Michigan; Ann Arbor Michigan USA
3. Department of Geosciences; Pennsylvania State University; University Park Pennsylvania USA
4. Now at College of Earth, Ocean and Atmospheric Sciences; Oregon State University; Corvallis Oregon USA
5. Division of Geological and Planetary Sciences; California Institute of Technology; Pasadena California USA
6. Now at U.S. Geological Survey; Reston Virginia USA
7. State Key Laboratory of Earthquake Dynamics; Institute of Geology, China Earthquake Administration; Beijing China
8. Lanzhou Institute of Seismology; China Earthquake Administration; Lanzhou China