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| Titel |
Tsunami risk assessment in the Marquesas Islands (French Polynesia) through numerical modeling of generic far-field events |
| VerfasserIn |
H. Hébert, F. Schindelé, P. Heinrich |
| 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.233-242 |
| Datensatznummer |
250000228
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| Publikation (Nr.) |
 copernicus.org/nhess-1-233-2001.pdf |
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| Zusammenfassung |
| Earthquakes
occurring at the Pacific Rim can trigger tsunamis that propagate across
the ocean and can produce significant damages far away from the source. In
French Polynesia, the Marquesas Islands are the most exposed to the
far-field tsunami hazards, since they are not protected by any outer coral
reef and since submarine slopes are less steep than in other islands.
Between 1994 and 1996, four tsunamis have reached the bays of the
archipelago, among them, the tsunami initiated by the Chilean Mw 8.1
earthquake, produced up to 3 m high waves in Tahauku Bay. Numerical
modeling of these recent events has already allowed us to validate our
method of resolution of hydrodynamics laws through a finite-difference
scheme that simulates the propagation of the tsunamis across the ocean and
computes the inundation heights (run-up) in remote bays. We present in
this paper the simulations carried out to study potentially threatening
areas located at the Pacific Rim, on the seismogenic Aleutian and Tonga
subduction zones. We use a constant seismic moment source (that of the Mw
8.1 Chile 1995 earthquake, M0 = 1.2 1021 N.m)
located at several potential epicenters, with the fault strike adapted
from the regional seismotectonics pattern. Our results show that the
sources chosen in the Aleutian trench do not produce large inundations in
the Marquesas bays, except for the easternmost source (longitude 194° E).
Sources located in the Tonga trench do not produce high amplifications
either, except for the northernmost one (latitude 16° S). We also discuss
the behaviour of the tsunami waves within the archipelago, and evidence
contrasting responses depending on the arrival azimuths. These results
show that, for a given initial seismic energy, the tsunami amplification
in remote bays is highly dependent on the source location and fault
strike. |
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