Seabed gas emissions and submarine landslides off SW Taiwan

Shu Kun Hsu, Shiao Shan Lin, Shiou Ya Wang, Ching Hui Tsai, Wen Bin Doo, Song Chuen Chen, Jing Yi Lin, Yi Ching Yeh, Hsueh Fen Wang, Cheng Wei Su

Research output: Contribution to journalArticlepeer-review

14 Scopus citations

Abstract

Methane emissions out of the seabed could seriously affect Earth’s climate and are usually associated with the dissociation of gas hydrates stored in marine sediments on the continental margins. Spatially, gas emissions out of the seafloor are not evenly distributed in continental margins. Gas emissions out of the seabed generally occur through submarine mud volcanoes and gas seeps. To understand the seabed gas emissions off SW Taiwan, we investigate the distributions of active submarine mud volcanoes, gas seeps, and gas plumes off SW Taiwan. We examine all of the available sub-bottom profiler and EK echo sounder data. We identified 19 submarine mud volcanoes, 220 gas seeps, and 295 gas plumes. The gas emissions are generally distributed at the crests of mud diapiric ridges. Most of the active mud volcanoes and gas seeps cluster at the KASMVG (Kaoping submarine mud volcanoes group) area. We speculate that the intensive mud volcanism and gas seepage at the KASMVG area are ascribed to submarine channel erosion along the continental slope base. The erosion causes a deep V-shaped channel and a steep BSR (Bottom-Simulating Reflector) slope curve across the continental margin. The upward migration rate of free gas beneath the BSR is thus increased and intensifies mud volcanism and gas seepage at the KASMVG area. The gas seeps can reduce the slope stability and generate small-scale slides. The development of mud volcanoes in an area could effectively disturb the seabed morphology so that large-scale submarine landslides cannot easily happen.

Original languageEnglish
Pages (from-to)7-15
Number of pages9
JournalTerrestrial, Atmospheric and Oceanic Sciences
Volume29
Issue number1
DOIs
StatePublished - Feb 2018

Keywords

  • Gas hydrate
  • Gas plume
  • Gas seeps
  • Mud volcano
  • Submarine landslide

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