Records of submarine natural hazards off SW Taiwan
Published:January 01, 2012
Chih-Chieh Su, Jing-Yi Tseng, Ho-Han Hsu, Cheng-Shing Chiang, Ho-Shing Yu, Saulwood Lin, James T. Liu, 2012. "Records of submarine natural hazards off SW Taiwan", Natural Hazards in the Asia–Pacific Region: Recent Advances and Emerging Concepts, J. P. Terry, J. Goff
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In the past few years, large earthquakes and torrential rain hit southern Taiwan and induced severe submarine hazards off the SW coast. Marine sediments (turbidites) provide valuable records with which to study and understand the formation of these submarine geo-hazards. The Pingtung Earthquake (two major events (ML=7.0) plus many aftershocks), on 26 December 2006, triggered turbidity currents that severed submarine cables in the Fangliao and Gaoping submarine canyons. This caused significant economic loss. In addition to earthquake activity, typhoons and torrential rains that induced flooding are also important mechanisms responsible for the formation of turbidites. On 8–9 August 2009 Typhoon Morakot brought heavy rains to southern Taiwan, causing serious landslides and flooding on land. The typhoon also caused submarine cable breaks in the Gaoping Canyon. All such events are likely to be recorded in the marine sediments of the canyon system, and by analysing these records we may be able to reconstruct the history of past earthquakes and floods in the region. Chirp sonar profiles, in conjunction with core analysis, including X-ray radiographs, grain size and 210Pb analysis, are used to identify the sources, transport and deposition of the turbidites (or hyperpycnite) and to reconstruct the history of earthquakes and flooding in the study area. Results indicate that these submarine hazards are not only related to earthquake and floods but that the unique geological and hydrological setting also plays an important role in the initiation of these submarine geo-hazards.
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Natural Hazards in the Asia–Pacific Region: Recent Advances and Emerging Concepts
Even a cursory glance at any map of the Asia–Pacific region makes a striking impression: in addition to the large continental landmass the region encompasses a truly vast expanse of ocean, dispersed over which are thousands of islands. Many might say that it could not be a worse time to live in this region. In the past few years we have experienced not only a number of devastating tsunamis (Indonesia, Solomon Islands, Samoa, Japan), but should not forget either the seemingly endless list of other natural hazards such as tropical cyclones and typhoons, volcanic eruptions, river floods and wildfires, amongst numerous others. This Special Publication represents an important collection of both conceptual and first-hand field investigations across the Asia–Pacific region. By highlighting some of the recent advances and emerging ideas in natural hazards research, the volume draws together these disparate lines of evidence into a clear regional focus.