Submarine landslides of the Antarctic Peninsula accretionary wedge: competing effects of tectonics, gas hydrates and glaciomarine sedimentation

High-latitude continental margins host some of the largest submarine landslide worldwide. Much speculation has focused on their relationship to glaciomarine sedimentation, gas hydrates and seismic shaking and, ultimately, the climatic variations that link to the former three factors. In this study we aim to better understand the causal mechanisms of such events in high-latitude margins. We focus on the Antarctic continental margins, particularly the Pacific Margin of the Antarctic Peninsula, which have been less studied than its Arctic counterparts. We use a combined dataset of archive and recently acquired swath bathymetry and seismic data. Two distinct submarine landslide groups are identified according to the water depth they show up. The shallowest cluster has mode depth centered around 1500 mwd, while the deepest cluster mode depth is centered around 4500 mwd. Most of their source areas are in 15-20 º slopes and, opposed to the Arctic counterparts, exhibit relatively small magnitudes, ranging from 0.1 to 10 km² in areal extent and between 0.1 to 1 km³ in volume. The identified submarine landslides are mainly located in tectonically active environments. In addition to glaciomarine sedimentation, both tectonics and gas hydrates, may act as triggering mechanisms for submarine landslides in the Antarctic Peninsula margin. Few landslides occur in gas hydrate bearing sediments, as evidenced by the occurrence of a BSR, and there is no evidence of submarine landslides rooted at the base of the gas hydrate stability zone. Approximately one half of the landslides occur along the area dominated by the glaciomarine sedimentary wedge, but the location of the deepest landslide cluster lays outside this wedge. Overall, high-exponents of a power-law fit to the frequency-magnitude relationship and fault-landslide neighborhood relationships suggest a potential seismic control on submarine landslide occurrence.