RATZOV , Gueorgui

The aim of this study is to constrain recent deformation of an active margin, using superficial structures deposits on the medium (Quaternary) to short (kyr to a century) term.The Ecuadorian margin is characterised by a tectonic erosion regime evolving northward, in Colombia, to a tectonic accretion. The margin undergoes strong seismicity, with...

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The morphology of Patia and Mira canyons on the South Colombian convergent margin reflects an interplay between tectonic deformation, sea-level variation and canyon evolution, and provides new insight into the age and location of margin deformation over the last ~ 150 ka. Multibeam bathymetry, seismic, and sedimentary data reveal that...

Shelf promontories exhibit very specific bathymetric features with regards to tsunamis. Because of their submerged cape morphology, a potential tsunami generated seawards of the promontory will exhibit a specific mode of propagation and coastal impact. To identify this peculiar tsunami signature, the Atacames Promontory, Ecuador, was chosen as...

Investigations of Mass-Transport Deposits (MTDs) and turbidite deposition in the confined North Ecuador subduction trench provide access to paleoseismic information and insights into long-term mechanisms for frontal tectonic erosion at a convergent margin. The studied trench has been the site of four great subduction earthquakes (7.7 ≤ Mw ≤...

Recent deep marine sedimentation in subduction trenches ischaracterized by the inter-stratification of hemipelagic and turbiditesediments locally interbedded with debris flows, which canresult from continental slope shaking by large earthquakes. Theobjective of this study is to describe the morphologic complexityon the Ecuadorian border of the...

The active margin of Ecuador is characterized by strong tectonic erosion that contributes to the formation of adeep trench filled by a complex suite of sedimentary facies. Gravity flow sedimentation is ubiquitous along themargin and facies range from laterally continuous m-thick mass transport deposits to isolated cm-thick...

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International audience

The initial sediment lithification reactions start with complex interactions involving all components of the sedimentary material (minerals, surface water, decomposing organic matter and living organisms). This is the eogenesis domain (0 to 2000 m below seafloor), covering a burial interval ranging from the interface with the biosphere down to...

International audience

International audience

Ongoing evidence for earthquake clustering calls for records of numerous earthquake cycles to improve seismic hazard assessment, especially where recurrence times overstep historical records. We show that most turbidites emplaced at the Africa-Eurasia plate boundary off west Algeria over the past ∼8 k.y. correlate across sites fed by...

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The Taiwan area, where the Philippine Sea Plate collides with Eurasia, is one of the most seismically active areas in the world and has been consequently struck repeatedly by destructive earthquakes. To better constrain the occurrence of large earthquakes, we have conducted two cruises in 2012 and 2013 from which five piston, gravity and...

La ride de Carnegie est un plateau océanique résultant de l'interaction Miocène à actuel entre lepoint chaud des Galápagos et la dorsale Nazca-Cocos. Sur les flancs de cette ride, la couverturesédimentaire carbonatée montre des zones parsemées de champs de dépressions sub-circulaires fermées,de 2 à 3 km de diamètre, parfois de 300 à 400 m de...

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Recent sedimentary facies and processes along the offshore slope of east Taiwan are investigated using a large set of geophysical and sedimentological data. The Taiwan orogen is often considered as one of the most tectonically active regions in the world and also suffers important climatic activity with an average of four typhoons per year. We...

The tectonic evolution of the Black Sea (BS) is a subject of debate, there are several unsolved questions: 1) the timing and the spatial progression of the BS basin opening and 2) the timing of Cenozoic shortening along the northern margin of the Eastern BS basin. The timing of the main compressional deformations, related to the inversion of...

Three main types of factors commonly control the nature of the clasts, the arrangement of the distinctive lithologies, and the general architecture of turbidite systems: sedimentation rate and carbonate production; climates and glacio-eustatism; and morphology and tectonics. The coexistence of adjacent systems of distinctive nature is, however,...

A morphometric analysis of submarine landslides on the continental slope of north Colombia – south Ecuador convergent margin provides insights into hazards, including mass movements locations, size of failures and location control. Bathymetric and seismic data acquired in 2005 revealed three distinctive types of locations with the occurrence of...

Northern Algeria is threatened by moderate to large magnitude earthquakes resulting from the slow convergence between the African and European plates. Main active faults are located offshore along the Algerian coast, as exemplified by the 2003 Mw 6.8 Boumerdès earthquake. This event triggered numerous and widespread turbidity currents over ∼...

Taiwan is a young and seismically active mountain belt, where a series of strong earthquakes (M>7) have occurred over the past hundred years. Identifying historical earthquakes around Taiwan is a key to better constrain the geodynamic of this active region. Sedimentological and geochemical analyses of surface sediments from one station offshore...

The relative motion of the Pacific plate with respect to the North America plate is partitioned between transcurrent faults located along the western margin of Baja California and transform faults and spreading ridges in the Gulf of California. However, the amount of right lateral offset along the Baja California western margin is still...