On Tuesday, March 27, 2018, Sirel Colon Useche, a PhD student in Earth and Universe and Environmental Sciences at theInstitute of Earth Sciences (ISTerre), will submit her thesis "Recent sedimentation on the northern Venezuelan margin (central coastline): superimposed record of climate-induced instabilities and consequences of seismic activity (landslides, tsunamis)".
The defense will take place at 2:30 pm, in the Jean-Paul Gidon room on the Bourget-du-Lac campus.
Summary of the thesis
The northern edge of Venezuela (southern edge of the Caribbean Plate) corresponds essentially to a relay of large active strike-slip faults, generating a steep, rugged margin (Southern Caribbean Sea, Cariaco Trough and Gulf, Fig. 1). This region is therefore exposed to three sources of natural hazards: 1) earthquakes and their direct effects, 2) tsunamis (linked to these faults, to the more distant activity of the Arcs Antillais, or to submarine landslides), 3) airborne landslides and flows, sometimes linked to sudden climatic events (cf. Vargas flash flood, December 1999). The second and third types of phenomena directly affect sedimentation, either marine (coastline and platform) or in lagoons and lakes. In addition, the latest (rapid) global variations in sea level have subdivided and structured the sedimentary pile. The recent part of these deposits (approx. 150,000 to 200,000 years ago) has been the subject of two preliminary high-resolution seismic imaging campaigns, the first dedicated to the eastern part (Gulf of Cariaco; Audemard et al., 2007; Van Daele et al., 2010) and the second to the central coastline (between Cabo Codera and Golfe Triste, Fig. 2). This second mission will be completed by a new acquisition of imagery and the taking of short cores at sea and in coastal lagoons.