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Titel |
Submarine mass wasting and associated tsunami risk offshore western Thailand, Andaman Sea, Indian Ocean |
VerfasserIn |
J. M. Schwab, S. Krastel, M. Grün, F. Gross, P. Pananont, P. Jintasaeranee, S. Bunsomboonsakul, W. Weinrebe, D. Winkelmann |
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 ; 12, no. 8 ; Nr. 12, no. 8 (2012-08-17), S.2609-2630 |
Datensatznummer |
250011053
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Publikation (Nr.) |
copernicus.org/nhess-12-2609-2012.pdf |
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Zusammenfassung |
2-D seismic data from the top and the western slope of Mergui Ridge in water
depths between 300 and 2200 m off the Thai west coast have been investigated
in order to identify mass transport deposits (MTDs) and evaluate the
tsunamigenic potential of submarine landslides in this outer shelf area.
Based on our newly collected data, 17 mass transport deposits have been
identified. Minimum volumes of individual MTDs range between 0.3 km3
and 14 km3. Landslide deposits have been identified in three different
settings: (i) stacked MTDs within disturbed and faulted basin sediments at
the transition of the East Andaman Basin to the Mergui Ridge; (ii) MTDs within
a pile of drift sediments at the basin-ridge transition; and (iii) MTDs
near the edge of/on top of Mergui Ridge in relatively shallow water depths
(< 1000 m). Our data indicate that the Mergui Ridge slope area seems to have
been generally unstable with repeated occurrence of slide events. We find
that the most likely causes for slope instabilities may be the presence of
unstable drift sediments, excess pore pressure, and active tectonics. Most
MTDs are located in large water depths (> 1000 m) and/or comprise small
volumes suggesting a small tsunami potential. Moreover, the recurrence rates
of failure events seem to be low. Some MTDs with tsunami potential, however,
have been identified on top of Mergui Ridge. Mass-wasting events that may
occur in the future at similar locations may trigger tsunamis if they
comprise sufficient volumes. Landslide tsunamis, emerging from slope
failures in the working area and affecting western Thailand coastal areas
therefore cannot be excluded, though the probability is very small compared
to the probability of earthquake-triggered tsunamis, arising from the Sunda
Trench. |
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