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| Titel |
Tsunami waveform inversion by numerical finite-elements Green’s functions |
| VerfasserIn |
A. Piatanesi, S. Tinti, G. Pagnoni |
| 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 ; 1, no. 4 ; Nr. 1, no. 4, S.187-194 |
| Datensatznummer |
250000223
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| Publikation (Nr.) |
 copernicus.org/nhess-1-187-2001.pdf |
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| Zusammenfassung |
| During the
last few years, the steady increase in the quantity and quality of the
data concerning tsunamis has led to an increasing interest in the
inversion problem for tsunami data. This work addresses the usually
ill-posed problem of the hydrodynamical inversion of tsunami tide-gage
records to infer the initial sea perturbation. We use an inversion method
for which the data space consists of a given number of waveforms and the
model parameter space is represented by the values of the initial water
elevation field at a given number of points. The forward model, i.e. the
calculation of the synthetic tide-gage records from an initial water
elevation field, is based on the linear shallow water equations and is
simply solved by applying the appropriate Green’s functions to the known
initial state. The inversion of tide-gage records to determine the initial
state results in the least square inversion of a rectangular system of
linear equations. When the inversions are unconstrained, we found that in
order to attain good results, the dimension of the data space has to be
much larger than that of the model space parameter. We also show that a
large number of waveforms is not sufficient to ensure a good inversion if
the corresponding stations do not have a good azimuthal coverage with
respect to source directivity. To improve the inversions we use the
available a priori information on the source, generally
coming from the inversion of seismological data. In this paper we show how
to implement very common information about a tsunamigenic seismic source,
i.e. the earthquake source region, as a set of spatial constraints. The
results are very satisfactory, since even a rough localisation of the
source enables us to invert correctly the initial elevation field. |
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