On Tuesday, March 27, 2018, Sirel Colon Useche, a doctoral student in Earth, Universe, and Environmental Sciences atthe Institute of Earth Sciences (ISTerre), will defend her dissertation titled “Recent Sedimentation on the Northern Venezuelan Margin (Central Coast): a superimposed record of climate-induced instabilities and the consequences of seismic activity (landslides, tsunamis).”
The defense will take place at 2:30 p.m. in the Jean-Paul Gidon Room on the Bourget-du-Lac campus.
Thesis summary
The northern margin of Venezuela (the southern margin of the Caribbean Plate) essentially consists of a series of large active strike-slip faults, which form a steep and rugged margin (southern Caribbean Sea, Cariaco Trench 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 more distant activity in the Antilles Arcs, or to submarine landslides), 3) landslides and debris flows, sometimes linked to extreme weather events (e.g., the Vargas flash flood, December 1999). The second and third types of phenomena directly affect sedimentation, whether marine (coastal and continental shelf) or lagoon and lake-based. Furthermore, recent (rapid) global sea-level fluctuations have subdivided and structured the sedimentary sequence. The recent portion of these deposits (approx. 150,000 to 200,000 years old) has been the subject of two preliminary high-resolution seismic imaging campaigns, the first focused on the eastern part (Gulf of Cariaco; Audemard et al., 2007; Van Daele et al., 2010) and the second to the central coast (between Cabo Codera and the Golfe Triste, Fig. 2). This second mission will be supplemented by new imaging data and the collection of short cores at sea and in coastal lagoons.