1. Institute for Geophysics, Jackson School of Geosciences University of Texas at Austin Austin TX USA
2. Cecil H. and Ida M. Green Institute of Geophysics and Planetary Physics, Scripps Institution of Oceanography University of California, San Diego La Jolla CA USA
3. Nevada Seismological Laboratory University of Nevada, Reno Reno NV USA
4. School of Oceanography University of Washington Seattle WA USA