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Titel |
Internal structure of event layers preserved on the Andaman Sea continental shelf, Thailand: tsunami vs. storm and flash-flood deposits |
VerfasserIn |
D. Sakuna-Schwartz, P. Feldens, K. Schwarzer, S. Khokiattiwong, K. Stattegger |
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 Sciences ; 15, no. 6 ; Nr. 15, no. 6 (2015-06-12), S.1181-1199 |
Datensatznummer |
250119529
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Publikation (Nr.) |
copernicus.org/nhess-15-1181-2015.pdf |
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Zusammenfassung |
Tsunami, storm and flash-flood event layers, which have been deposited over
the last century on the shelf offshore Khao Lak (Thailand, Andaman Sea), are
identified in sediment cores based on sedimentary structures, grain size
compositions, Ti / Ca ratios and 210Pb activity. Individual offshore
tsunami deposits are 12 to 30 cm in thickness and originate from the 2004
Indian Ocean Tsunami. They are characterized by (1) the appearance of sand
layers enriched in shells and shell debris and (2) the appearance of mud and
sand clasts. Storm deposits found in core depths between 5 and 82 cm could
be attributed to recent storm events by using 210Pb profiles in
conjunction with historical data of typhoons and tropical storms. Massive
sand layers enriched in shells and shell debris characterize storm deposits.
The last classified type of event layer represents reworked flash-flood
deposits, which are characterized by a fining-upward sequence of muddy
sediment. The most distinct difference between storm and tsunami deposits is
the lack of mud and sand clasts, mud content and terrigenous material
within storm deposits. Terrigenous material transported offshore during the
tsunami backwash is therefore an important indicator to distinguish between
storm and tsunami deposits in offshore environments. |
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