Abstract

3-D seismic reflection data and a variance cube are used to determine the architecture and investigate the triggering processes of submarine landslides affecting the flanks of a Miocene carbonate platform in the Luconia Province, Malaysia. The slide masses exhibit, in time-slice displays, chaotic, patchy seismic patterns, in otherwise smooth reflections. They lie basinward of the slide scar, tend to widen in the transport direction, and end in indistinct lobes. Slide scars appear as crescent-shaped embayments in otherwise straight or oval platform-edge contours. However, slide scars show planar morphology where they coincide with a fault zone. In vertical sections, the basal surfaces of the slides are steep concave slope segments (slide scar) that rapidly flatten where they dip under the slide masses. Slide masses appear as zones of discontinuous wavy reflections that wedge out in both upslope and downslope directions, extend for 1.5 km into the basin, and have a maximum thickness of 130 m. The slide deposit on the western flank is the result of at least two individual sliding events. Two seismically chaotic bodies are separated by a smooth reflection interpreted as an intercalation of hemipelagic mud between carbonaterich slide masses. Syndepositional faulting affects the geometry of the platform and the platform margins, particularly at the time of slope failure. We suggest that the slides were generated by the interplay of steep-slope progradation and faulting accompanied by seismic shocks.