Mass wasting at the base of the south central Chilean continental margin: the Reloca Slide

Offshore south central Chile (35° S-42° S), the morphology of the lowermost continental slope and trench floor witnesses a voluminous submarine mass-wasting event. The blocky slide body deposited in the Chile Trench at 73°46ʹ W 35°35ʹ S was targeted for study during RRS JAMES COOK Cruise JC23 and termed Reloca Slide. Its size of about 24 km3, its steep and high headscarp, the spatial distribution of slide deposits and the cohesive nature of major slide blocks make it interesting to address the issue of tsunami generation. We have obtained seismic reflection data that partly reveal the internal structure of the slide body. Gravity core samples were retrieved that will allow the slide to be dated and linked to the history of sedimentation and slope stability along this particular segment of the Chilean convergent margin. At present we assume a Holocene age for the sliding event.