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| Titel |
Earthquake related tsunami hazard along the western coast of Thailand |
| VerfasserIn |
F. Løvholt, H. Bungum, C. B. Harbitz, S. Glimsdal, C. D. Lindholm, G. Pedersen |
| 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 ; 6, no. 6 ; Nr. 6, no. 6 (2006-11-30), S.979-997 |
| Datensatznummer |
250003809
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| Publikation (Nr.) |
 copernicus.org/nhess-6-979-2006.pdf |
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| Zusammenfassung |
| The primary background for the present study was a project to assist the
authorities in Thailand with development of plans for how to deal with the
future tsunami risk in both short and long term perspectives, in the wake of
the devastating 26 December 2004 Sumatra-Andaman earthquake and tsunami. The
study is focussed on defining and analyzing a number of possible future
earthquake scenarios (magnitudes 8.5, 8.0 and 7.5) with associated return
periods, each one accompanied by specific tsunami modelling. Along the most
affected part of the western coast of Thailand, the 2004 tsunami wave caused a
maximum water level ranging from 5 to 15 m above mean sea level. These
levels and their spatial distributions have been confirmed by detailed
numerical simulations. The applied earthquake source is developed based on
available seismological and geodetic inversions, and the simulation using
the source as initial condition agree well with sea level records and run-up
observations. A conclusion from the study is that another megathrust
earthquake generating a tsunami affecting the coastline of western Thailand is not
likely to occur again for several hundred years. This is in part based on
the assumption that the Southern Andaman Microplate Boundary near the
Simeulue Islands constitutes a geologic barrier that will prohibit
significant rupture across it, and in part on the decreasing subduction
rates north of the Banda Ache region. It is also concluded that the largest
credible earthquake to be prepared for along the part of the Sunda-Andaman
arc that could affect Thailand, is within the next 50–100 years an
earthquake of magnitude 8.5, which is expected to occur with more spatial
and temporal irregularity than the megathrust events. Numerical simulations
have shown such earthquakes to cause tsunamis with maximum water levels up
to 1.5–2.0 m along the western coast of Thailand, possibly 2.5–3.0 m on a high
tide. However, in a longer time perspective (say more than 50–100 years) the
potentials for earthquakes of similar magnitude and consequences as the 2004
event will become gradually larger and eventually posing an unacceptable
societal risk. These conclusions apply only to Thailand, since the effects
of an M 8.5 earthquake in the same region could be worse for north-western
Sumatra, the Andaman and Nicobar Islands, maybe even for Sri Lanka and parts
of the Indian coastline. Moreover, further south along the Sunda arc the
potentials for large ruptures are now much higher than for the region that
ruptured on 26 December 2004. |
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