CDSA: A New Seismological Data Center for the French Lesser Antilles

Abstract

International audienc

Seismic activity offshore Martinique and Dominica islands (Central Lesser Antilles subduction zone) from temporary onshore and offshore seismic networks

“…Offshore Martinique different destructive and moderate earthquakes, with reported intensity between V to IX, occurred from 1702 to 1839 (Bernard and Lambert, 1988;Dorel, 1981;Dorel et al, 1971;Feuillet et al, 2002;Robson, 1964). Dorel (1981) and Bengoubou-Valérius et al (2008) noted that the northern sector of the arc (north of 14°N) was substantially more active than the southern one. Large instrumental earthquakes (M N 6) occurring in this portion of the arc (Fig.…”

“…Dorel, 1981). French volcanological and seismological observatories of Guadeloupe and Martinique continuously record seismicity since a long time and the general seismic pattern is well known (Bengoubou-Valérius et al, 2008). However locations of small magnitude earthquake east of the volcanic arc, over the potential seismogenic zone, are poorly constrained by the permanent seismic network deployed on the islands.…”

Probabilistic Seismic Hazard Assessment for Bridgetown-Barbados, Employing Subduction Interface Characteristic Earthquakes

“…Due to the proximity of Barbados to the interface subduction zone, we consider it is very important to improve the tectonic model by including a more realistic geometry of the inclined slab beneath the island in the hazard calculations. The focal mechanisms of deeper intra-plate events (> 50 km) indicate that there is normal faulting resulting from initial flexure of the down going Atlantic slab (Zone 4 and 5) with an average westward dipping angle of 50º [11]. Zones 2 and 4 cover the latitudes from 14.8º N to 20.0º N and they are characterized with a higher seismic activity than Zone 3 and 5 (from 11.0º N to 14.8º N latitude).…”

“…Zones 2 and 4 cover the latitudes from 14.8º N to 20.0º N and they are characterized with a higher seismic activity than Zone 3 and 5 (from 11.0º N to 14.8º N latitude). Bengoubou-Valeruis et al [11] and Russo et al [12] attribute the differences in the seismic activity to the following reasons: (1) changes in the tectonic structures mapped by Feuillet et al [13]; (2) there being enough sediments to lubricate or decouple the two plates in the subduction zone; (3) strengthening caused by thick accretionary prism overburden which lies above the shallow reach of the subduction zone. The quiescent area coincides with the deepest part of the Barbados accretionary wedge.…”

Validation of Teleseismic Inversion of the 2004 Mw 6.3 Les Saintes, Lesser Antilles, Earthquake by 3D Finite-Difference Forward Modeling

“…1). According to the importance of the regional seismic hazard, a dense local seismic network has been set up in the french territory (e.g., Bengoubou-Valérius et al, 2008;Pequegnat et al, 2008). The local network locates the hypocenter of the 2004 earthquake at 14 km depth and the epicenter at 15.76°N and 61:53°E (Bertil et al, , 2005 distribution implies the extent of the ruptured area but does not indicate a clear fault plane (Bertil et al, 2005).…”