Xiaohua Xu¹, Lauren Ann Ward², Bridget R Smith-Konter², Christopher William Douglas Milliner³, Peng Fang¹, Yehuda Bock¹ and David T Sandwell¹, (1)Scripps Institution of Oceanography, Institute of Geophysics and Planetary Physics, La Jolla, CA, United States, (2)University of Hawaii at Manoa, Earth Sciences, Honolulu, HI, United States, (3)Univserity of Southern California, Venice, CA, United States