Sediment distribution on the inner continental shelf off Khao Lak (Thailand) after the 2004 Indian Ocean tsunami
Sediment distribution on the inner continental shelf off Khao Lak (Thailand) after the 2004 Indian Ocean tsunami
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DOI：
10.5047/eps.2011.09.001
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发表时间：
2012-01-01
影响因子：
3
通讯作者：
Sompongchaiyakul, P.
中科院分区：
文献类型：
--
作者：
Feldens, P.;Schwarzer, K.;Sompongchaiyakul, P.
考拉克（泰国）的海岸线在 2004 年印度洋海啸中遭到严重破坏。陆上海啸沉积物和卫星图像显示大量沉积物被输送到近海，表明海底受到海啸上升和反冲洗的影响。在这项研究中，提供了沉积物分布模式和海底地质发育的高分辨率地图。这些地图基于考拉克近海的多波束、侧扫声纳和地震剖面调查。古礁石以及相关的巨石场和沙质沉积物主导着内陆架。水深小于 15 m 时存在细粒（淤泥至细砂）沉积物斑块。 2008 年至 2010 年间，除了细粒沉积物斑块边界出现小幅变化外，沉积物分布格局保持稳定。在一个沉积物岩心和几个抓取样本中记录了一个事件层，该事件层位于厚度仅几厘米的现代沉积物覆盖层下方。事件层可追溯到 18 m 水深。它主要由沙子组成，并含有陆源化合物。它被解释为 2004 年印度洋海啸沉积物。然而，在研究地点的大片区域，海啸的影响很难通过海底形态或沉积物分布来识别。
The coastline of Khao Lak (Thailand) was heavily damaged by the 2004 Indian Ocean tsunami. Onshore tsunami deposits and satellite images, which show large amounts of sediment transported offshore, indicate that the seafloor was impacted by tsunami run-up and backwash. In this study, high-resolution maps of sediment distribution patterns and the geological development of the seafloor are presented. These maps are based on multibeam, side-scan sonar and seismic profiling surveys offshore Khao Lak. Paleoreefs, with associated boulder fields and sandy sediment dominate the inner continental shelf. Patches of fine-grained (silt to fine sand) sediments exist in water depths of less than 15 m. The sediment distribution pattern is stable between 2008 and 2010, apart from small shifts regarding the boundaries of the fine-grained sediment patches. In one sediment core and several grab samples an event layer was documented, situated below a cover of modern sediments which is only a few cm thick. The event-layer is traced down to 18 m water depth. It consists mostly of sand and contains compounds of terrigenous origin. It is interpreted as a 2004 Indian Ocean tsunami deposit. However, over large areas of the study-site, the impact of the tsunami is hardly identifiable by seafloor morphology or sediment distribution.