Presentation

Léa POUSSE BELTRAN — 2025-06-02T15:40:16Z

POSITION ACTUELLE :

2022 Chargée de Recherche IRD / Active Tectonics

EDUCATION :

2013 - 2016
Thèse en Géologie à ISTerre
Titre : « L'aléa sismique le long des grands décrochements vénézuéliens ».
Soutenue le 8/12/2016
Directeurs de thèse : Dr. R. Vassallo et Pr. F. Jouanne.

2010 - 2012
Cycle d'ingénieur-géologue
École Nationale Supérieure de Géologie (ENSG, Nancy, France)
Spécialité Géotechnique.

Thèse : L'aléa sismique le long des grands décrochements vénézueliens

Léa POUSSE BELTRAN — 2014-06-02T08:20:29Z

Keyword : morphotectonics, cosmogenic nuclides dating, paleoseismology, geodesy, InSAR, GPR

Seismic hazard characterization of a region requires knowledge of (1) the return period of major earthquakes, (2) seismic/aseismic behavior of faults and possible roughness of the fault plane, (3) locking depths related to the crust rheology and (4) the fault rate. The proposed approach combines morphotectonic/paleoseismologic analysis, GPS and InSAR to address these issues using data on the active deformation on complementary time scales. Northern Venezuela (Fig.1), with major right strike-slip faults (Oca - Ancon - Bocono- San Sebastian - El Pilar), is a tectonically active and populated region, and we believe that the results of this study will be a fundamental part for a better understanding of the regional geodynamics and for the assessment of the seismic hazard.

Figure 1 : Location of major venezuelan faults, and of the Yaracuy valley.

In particular, we will focus these studies on the northernmost segment of Bocono Fault, in the Yaracuy valley (Fig. 1) where paleoseismologic calendar as of now is very incomplete and the distribution of deformation on this fault poorly known.To perform an acurrate determination of slip rate along this segment of the Bocono Fault we map, measure and sample the alluvial fans offset by fault (Fig. 2), in order to date them by 10Be TCN.

Paleoseismologic trenching through the same fault allow us to study the geometries of coseismic ruptures and date (14C, OSL) sedimentary horizons that surround these events. Three trenching sites (Fig. 2, 3) have been preselected on the field and through studies of spatial images.

Figure 2 : Location of the preselected trenching sites and sampled area in the Yaracuy Valley.

Figure 3 : 10Be quartz sampling of the Yaritagua alluvial fan offset by the Bocono Fault.

Acknowledgments :

We thank Fundacion Venezolana de Investigaciones Sismolgicas (FUNVISIS) in particular Franck Audemard for yielding aerial photos, topographic map, archives, and the logistical support given during the field trip. We acknowledge GIAME, Fondo Na-
cional de Ciencia Tecnolog—a e Innovaci—on (FONACIT) and Evaluation - Orientation de la COopration Scienti-que (ECOS) (proyect : FONACIT-ECOS Nord PI 2009000818, FONACIT 2012002202 and 2013000361), for economical support during the fi-eld trip. We would like to thank the Fundacion Instituto de Ingeniera Laboratorio de Procesamiento Avanzado de Imagenes Satelitales LPAIS and ISIS-CNES for providing satellite images.

Dans le lien ci dessous, les financements du projet, rédigé par Riccardo VASSALLO :http://isterre.fr/annuaire/pages-web-du-personnel/riccardo-vassallo/article/alea-sismique-le-long-des-grands

ISTerre - Institut des Sciences de la Terre

Presentation

Thèse : L'aléa sismique le long des grands décrochements vénézueliens