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Optimal time alignment of tide‐gauge tsunami waveforms in nonlinear inversions: Application to the 2015 Illapel (Chile) earthquake
Author(s) -
Romano F.,
Piatanesi A.,
Lorito S.,
Tolomei C.,
Atzori S.,
Murphy S.
Publication year - 2016
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2016gl071310
Subject(s) - tide gauge , geology , waveform , seismology , bathymetry , inversion (geology) , nonlinear system , geodesy , slip (aerodynamics) , synthetic aperture radar , interferometry , tsunami earthquake , interferometric synthetic aperture radar , radar , remote sensing , computer science , tectonics , sea level , physics , oceanography , optics , telecommunications , quantum mechanics , thermodynamics
Tsunami waveform inversion is often used to retrieve information about the causative seismic tsunami source. Tide gauges record tsunamis routinely; however, compared to deep‐ocean sensor data, tide‐gauge waveform modeling is more difficult due to coarse/inaccurate local bathymetric models resulting in a time mismatch between observed and predicted waveforms. This can affect the retrieved tsunami source model, thus limiting the use of tide‐gauge data. A method for nonlinear inversion with an automatic optimal time alignment (OTA), calculated by including a time shift parameter in the cost function, is presented. The effectiveness of the method is demonstrated through a series of synthetic tests and is applied as part of a joint inversion with interferometric synthetic aperture radar data for the slip distribution of the 2015 M w 8.3 Illapel earthquake. The results show that without OTA, the resolution on the slip model degrades significantly and that using this method for a real case strongly affects the retrieved slip pattern.