Study about High Resolution Tsunami Inversion for Chile Earthquake in 2010

Abstract

We investigate the feasibility of inverting higher solution vertical seafloor displacement from tsunami waveforms. An inversion method named "SUTIM" (small unit tsunami inversion method) is developed to meet this goal. This paper improves the inversion resolution by using the Grid-Shifting method in addition to the traditional least-square inversion. In order to achieve stability, a smooth constraint is used. SUTIM is employed to analyze the 2010 Chile earthquake following a number of validation and performance tests. Based upon data quality and azimuthal distribution, we select tsunami waveforms from 6 GLOSS stations and 1 DART buoy record. In total, 157 sub-faults are utilized for the highresolution inversion. The resolution reaches 10 sub-faults per wavelength. The result is compared with the distribution of the aftershocks and waveforms at each gauge location with very good agreement. The inversion result shows that the source profile features a non-uniform distribution of the seafloor displacement. The highly elevated vertical seafloor is mainly concentrated in two areas: one is located in the northern part of the epicentre, between 34\(^{\circ}\)s and 36\(^{\circ}\)s; the other is in the southern part, between 37\(^{\circ}\)s and 38\(^{\circ}\)s. The study demonstrate the performance of SUTIM by simulating a fictitious earthquake event in which the seafloor motion is known. Good SUTIM performance can be seen.