Terr. Atmos. Ocean. Sci., Vol. 19, No. 6, 767-772, December 2008

doi: 10.3319/TAO.2008.19.6.767(PT)

Turbidity currents, submarine landslides and the 2006 Pingtung earthquake off SW Taiwan

Shu.-Kun Hsu1,*, Jackie Kuo2, Chung-Liang Lo1, Ching-Hui Tsai1, Wen-Bin Doo1, Chia-Yen Ku1 and Jean-Claude Sibuet3

1 Institute of Geophysics, National Central University , 300 Chungda Road , Chung-Li 32001, Taiwan
2 Chung Hwa Telcom Co. Ltd., 468 Sietian Road , Toucheng, Yilan 261, Taiwan
3 Institute of Applied Geosciences, National Taiwan Ocean University , 2 Pei-Ning Road Keelung 202, Taiwan


     Submarine landslides or slumps may generate turbidity currents consisting of mixture of sediment and water. Large and fast-moving turbidity currents can incise and erode continental margins and cause damage to artificial structures such as telecommunication cables on the seafloor. In this study, we report that eleven submarine cables across the Kaoping canyon and Manila trench were broken in sequence from 1500 to 4000 m deep, as a consequence of submarine landslides and turbidity currents associated with the 2006 Pingtung earthquakes offshore SW Taiwan. We have established a full-scale scenario and calculation of the turbidity currents along the Kaoping canyon channel from the middle continental slope to the adjacent deep ocean. Our results show that turbidity current velocities vary downstream ranging from 20 to 3.7 and 5.7 m s-1, which demonstrates a positive relationship between turbidity current velocity and bathymetric slope. The violent cable failures happened in this case evidenced the destructive power of the turbidity current to seafloor or underwater facilities that should not be underestimated.

Keywords: Submarine landslide, Turbidity current, Pingtung earthquake, SW Taiwan, Cable break

Citation: Hsu, S. K., J. Kuo, C. L. Lo, C. H. Tsai, W. B. Doo, C. Y. Ku, and J. C. Sibuet, 2008: Turbidity currents, submarine landslides and the 2006 Pingtung earthquake off SW Taiwan. Terr. Atmos. Ocean. Sci., 19, 767-772, doi: 10.3319/TAO.2008.19.6.767(PT)