23-25 September 2013
GEOMAR East shore
Europe/Berlin timezone
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Characteristics and mechanisms of the submarine landslides off SW Taiwan

Presented by Prof. Shu-Kun HSU on 23 Sep 2013 from 17:15 to 19:15
Type: Poster presentation
Session: Poster session

Content

The area off SW Taiwan is situated in an active convergent margin where the Eurasian Plate subducts eastwards beneath the Philippine Sea Plate. Because of the collision of the Luzon Arc (situated on the Philippine Sea Plate) against the Eurasian Plate margin, the area off SW Taiwan is also in an initial stage of orogeny. On the other hand, the area off SW Taiwan has a wide distribution of BSR (Bottom Simulating Reflector) indicating a high potential area of gas hydrate reservoir. Because of above two factors, submarine mud volcanoes, mud diapirs, pockamrks and gas seepages are widely distributed off SW Taiwan. As shown by the gas plumes (or gas “flares”) from 38 kHz echo sounder above some mud volcanoes, the gas emissions in the area off SW Taiwan are quite active. In consequence, several submarine landslides can be triggered. To understand the characteristics and mechanisms of the submarine landslides, we have compiled the distributions of the mud diapirs, mud volcanoes, gas seep sites and gas plumes locations. We have also conducted several multi-channel seismic reflection profilers across the continental margins. We also use multi-beam bathymetric data. We find that the submarine landslides generally occur along two main traces. The first trace is near continental break. The scales of those submarine landslides are general small. The submarine landslides are due to gravity instability near the continental break. Thus, the mass slumping is observed. Marked by the distribution of gas seeps, the second trace is near the bathymetric contour of 500 m. This water depth is close to the possible gas hydrate dissociation depth (pressure). A distinctive seafloor subsidence or faulting is present along this trace. This trace can be further separate into western and eastern portions. In the western portion, the mud volcanoes and gas plumes are not so active. Thus, clear failure surface in the seabed and displaced masses can be clearly observed. In contrast, in the eastern portion, the submarine mud volcanoes and gas plumes are very active. The gas supply from the free gas could be sufficiently. Clear failure surfaces can be observed only in the deeper part. However, the mass transport deposit (MTD) can be found at the feet of the active mud volcanoes. In our study area, the development of the submarine canyons is related to the occurrence of the mud diapirs. The channels of the submarine canyons have cut the continental slopes and also provide the lateral boundaries of the submarine landslides.

Place

Location: GEOMAR East shore
Address: Wischhofstr. 1-3 / D-24148 Kiel
Room: Lithothek

Primary authors

  • Prof. Shu-Kun HSU Department of Earth Sciences, National Central University, Taiwan
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Co-authors

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