Fangliao Slide — a large slope failure in the upper Kaoping Slope off southwest Taiwan

  • Author(s): Song-Chuen Chen, Ching-Hui Tsai, Shu-Kun Hsu, Yi-Ching Yeh, Char-Shine Liu, San-Hsiung Chung, and Cheng-Yueh Wei
  • DOI: 10.3319/TAO.2017.06.14.01
  • Keywords: Submarine landslide, Mud diapir, Gas hydrate, Southwest Taiwan
  • A large submarine landslide, Fangliao Slide, is discovered and described
  • The Fangliao Slide is linked to mud diapirism and gas hydrate dissociation
  • The boundaries of the Fanglaio Slide can be delineated from seismic profiles
Abstract

Based on seismic reflection profiles and multi-beam bathymetric data, a large submarine landslide named Fangliao Slide is mapped for the first time off SW Taiwan. The Fangliao Slideoccurred on the continental slope to the west of the Fangliao Canyon at water depths between 420 m and 900 m. The seafloor of the Fangliao Slide has a gentle slope angle (~1° to 2°). The landslide covers an area of ~15 km length and ~10 km width and a volume of ~26 km3. The headwall of the landslide has ~30 m vertical offset at the southern flank of mud diapir MD7-1, and the sidewalls are bounded by fault A in the west and faults C and D in the east. The sliding area is composed of five bathymetric terraces, indicating that the slope failures have occurred several times. The Fangliao Slide can be divided into an upper domain and a lower domain, separated at the water depth of ~600 m where the gas hydrate off SW Taiwan becomes dissociate. The initial slope failure of the Fangliao Slide was probably linked to mud diapirism of MD7-1 and the slope failure in the lower domain was probably augmented by the gas hydrate dissociation. The seafloor morphology in the lower domain is therefore more corrugated than in the upper domain.

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