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Titel |
Sensitivity of the adjoint method in the inversion of tsunami source parameters |
VerfasserIn |
C. Pires, P. M. A. Miranda |
Medientyp |
Artikel
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Sprache |
Englisch
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ISSN |
1561-8633
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Digitales Dokument |
URL |
Erschienen |
In: Natural Hazards and Earth System Science ; 3, no. 5 ; Nr. 3, no. 5, S.341-351 |
Datensatznummer |
250001233
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Publikation (Nr.) |
copernicus.org/nhess-3-341-2003.pdf |
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Zusammenfassung |
This paper tests a methodology for
tsunami wave-form inversion, based on the adjoint method. The method is
designed to perform the direct optimization of the tsunami fault
parameters, from tide-gauge data, imposing strong geophysical constrains
to the inverted solutions, leading to a substantial enhancement of the
signal-to-noise ratio, when compared with the classical technique based on
Green’s functions of the linear long-wave model. A 4-step inversion
proce-dure, which can be fully automated, consists (i) in the source area
delimitation by adjoint backward ray-tracing, (ii) ad-joint optimization
of the initial sea state, from a vanishing first-guess, (iii) non-linear
adjustment of the fault model and (iv) final adjoint optimization in the
fault parameter space. That methodology is systematically tested with four
different idealized bathymetry and coastline setups (flat bathymetry in an
open domain, closed conical circular lake, islands in an open domain and
submarine mountains in an open domain) and different amounts of synthetic
observation data, and of observational and bathymetric errors. Results
show that the method works well in the presence of reasonable amounts of
error and it provides, as a by-product, a resolution matrix that contains
information on the inversion error, identifying the combinations of source
parameters that are best and worst resolved by the inversion |
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