RRS Charles Darwin Cruise 108, 14 Sep-16 Oct 1997. TOBI and MULTIBEAM surveys of submarine landslides around the Canaries

The overall objective of the cruise was to examine the contribution of large-scale landsliding to the evolution of the western Canary Islands. Aims included the production of a comprehensive assessment of the effects of catastrophic landslides, including analysis of their frequency, triggering mechanisms and volumes, as well as studies of landsliding processes. The main tools used included swath bathymetry, TOBI high-resolution sidescan sonar and 3.5 kHz and seismic profiling. The survey programme concentrated on three areas where landsliding was believed to be most active: the northern flank of Tenerife, the flanks of the island of La Palma and the flanks of the island of El Hierro. The cruise was highly successful, obtaining swath bathymetry and EM12 sidescan sonar data covering much of the flanks of Tenerife, El Hierro and La Palma. Large-scale slope failures are more abundant on these island flanks than had previously been recognised and at least ten slope failure events can be recognised from the new data. TOBI sidescan sonar images from key areas show varied flow processes including debris avalanche, sediment slide and debris flow.