Presenter: Yi-Chen Chen
Date: 2017/01/05
Abstract
Margin basins in tectonically active areas typically contain turbidites that have been deposited from turbidity currents generated by seismic events. Some slope failures are triggered by earthquakes, and turbidites may provide a valuable long-term record of major earthquakes. Understanding the frequency of these flows, and their timing and triggers, is therefore important for understanding how sediment is transferred globally, effective recovery of oil and gas reserves, hazards of strategic cable networks, and the recurrent intervals of tsunamis and earthquakes. The result of sedimentary structures do not yield direct clues about the triggering force. We may therefore rely on other characteristics to define the probable trigger mechanism. This can be tested in modern locations where a dated turbidite can be matched with an historic earthquake or flood. Box and gravity coring have defined the areal distribution and volumes of turbidites laid down during historic time. The deposits have been dated by radiometric methods ( 210 Pb, 14 C), and by counting annual primary laminations. In the stratigraphic record, it would appear that the best criteria for defining seismo-turbidites from turbidites of other generating mechanisms are observed directly time of individual turbidites.
Reference
Chris Goldfinger. “Submarine paleoseismology based on turbidite records”, Annual Review of Marine Sciences, 3, pp. 35-66, 2011.
Chris Goldfinger, C. Hans Nelson, and Joel E. Johnson. “Holocene earthquake records from the Cascadia subduction zone and northern San Andreas fault based on precise dating of offshore turbidites”, Annual Review of Earth and Planetary Sciences, 31, 1, pp. 555-577, 2003.
Peter J. Talling, “On the triggers, resulting flow types and frequencies of subaqueous sediment density flows in different settings”, Marine Geology, 352, pp. 155-182, February 2014.
曾世霖，「台灣西南外海高屏峽谷沉積物及沉積機制研究」，國立中央大學，碩士論文，民國100年。
鄭屹雅，「臺灣西南海域沈積物重力流引發之海底電纜斷裂事件」，國立臺灣大學，碩士論文，民國101年。