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In order to improve our understanding of the marine slope instability of hydrate-bearing sediments in the offshore southwestern Taiwan, P- and S-waves seismic data generated by P-S conversion on reflection from airgun shots recorded from a multi-component Ocean Bottom Seismometer (OBS) survey were used to construct two-dimensional velocity model. The investigated profile lies above a structural high of the Yuan-An ridge, proposed as a high priority drilling site for gas hydrate investigations off southwest Taiwan. The locations of the OBSs were determined with high accuracy by an inversion based on the shot traveltimes. Traveltime inversion and forward modeling of seismic data result in general trends P- and S-wave velocities of sediments. Generally, P- and S-wave velocities are high beneath topographic ridges which might represent a series of thrust-cored anticlines develop in the accretionary wedge. P-wave velocities of the sea floor are about ~1.58 km s-1, increasing to the bottom simulating reflectors (BSR), reaching values of about ~2 km s-1. Below it, a low velocity layer (1.62 - 1.74 km s-1) is observed, which indicates the presence free gas in the sedimentary layer. S-wave velocities of the sediments over the entire section range from 0.3 to ~0.6 km s-1. Significant lateral velocity variations were found beneath the eastern flank of the Yuan-An ridge, probably represents thrust faults that extend from seafloor to hydrate-bearing layer. We suggest that the BSR has been disturbed by the thrust faults and further rupture of the fault could potentially trigger failures in the study area.
|Number of pages||12|
|Journal||Terrestrial, Atmospheric and Oceanic Sciences|
|State||Published - Feb 2018|
- Marine slope instability
- Ocean bottom seismometer
- Seismic velocity
FingerprintDive into the research topics of 'Imaging P- and S-wave velocity structures in hydrate bearing sediments along an OBS profile across the Yuan-An Ridge, off southwest Taiwan'. Together they form a unique fingerprint.
- 1 Finished
Marine geology and seabed stability study for the potential gas-hydrate area off SW Taiwan(I)
1/01/16 → 31/12/16