Time Reversal Imaging of Tsunami Source
Traditional source inversion using tsunamis waves is based on finite-fault slip modeling. Such inversion methods suffer from the uncertainty of fault parameters or crustal rigidity. Moreover, the heavy computational burden of calculating Green’s functions result in limited spatial resolution and hinders the real-time applicability of the traditional methods to tsunami early warning. Time reversal imaging aims at reconstructing the initial water elevation by back-propagation and constructive interference of the recorded tsunami waveforms (An and Meng, 2017). This method does not rely on pre-defined fault parameters, and is suitable for tsunami-generating earthquakes with unknown fault geometry. This method efficiently handles dense mesh grid and is capable of resolving small-scale secondary tsunami sources, such as the seafloor landslide or secondary ruptures on splay faults. We valid this approach with synthetic tsunami sources, and apply it to the 2014 Iquique tsunami event, and the 2015 Illapel event. The Time Reversal Imaging method is of high resolution and produces little artifacts. Time reversal imaging provides independent verification of the finite-fault models.