Voon Hui Lai, CalTech Seismological Laboratory, Pasadena, CA, United States, Zhongwen Zhan, California Institute of Technology, Seismological Laboratory, Pasadena, CA, United States and Quentin Brissaud, Institut Supérieur de l'Aéronautique et de l'Espace, SSPA/DEOS, Toulouse Cedex 04, France