M155 Fogo
Summary M155 - May 26th to June 30th, 2019 Pointe-á-Pitre (Guadeloupe) to Mindelo (Cape Verde)
RV Meteor-Cruise M155 realized two proposals with different objectives. The main part of the cruise was assigned to the proposal ‘The tsunamigenic gravitational flank collapse of Fogo volcano, Cape Verde Islands’. The cruise contributes to the assessment of poorly constrained and heavily debated tsunamigenic potential of large volcanic island flank collapses. The recent discovery of tsunamigenic deposits in the Cape Verdes shows that Fogo collapsed catastrophically at ~73 ka, resulting in a mega-tsunami. More This provides a unique opportunity to reconstruct the generation and impact of a mega-tsunami, directly linked to a study of its trigger mechanism. Accordingly, offshore collapse deposits were investigated by means of (1) high-resolution mapping with multibeam and side-scan sonar to accurately determine the run-out distance, and the number of collapse events; (2) seismic profiling to image the deposits’ thicknesses and internal structure; and (3) coring to establish a stratigraphy of collapse events. This study will put us at a critical juncture where the latest developments in tsunami modelling can be integrated with physical evidence from both the offshore and onshore. A smaller part of the cruise was assigned to the proposal ‘Seismic pre-site survey for an IODP site on the Cape Verde Plateau’. The IODP full-proposal ‘Cenozoic climate, productivity, and sediment transport at the NW African continental margin’ (IODP proposal 933-full) addresses Neogene climate, sedimentation and ocean productivity along the continental margin of NW Africa. A central site is proposed on the Cape Verde Plateau close to ODP Site 659 but no modern high-resolution seismic data are available for this area. A seismic survey around Site 659 would have aimed in identifying a location where the Plio-Pleistocene is thinner and the Miocene is thicker than at Site 659. This would allow to APC-XCB deeper into the Miocene. This part of the proposal, however, could not be realized due to a failure of the ship’s compressor.