caa a22 4500 463172264 CHVBK 20180406164816.0 cr unu---uuuuu 170326e20071001xx s 000 0 eng 10.1007/s10950-007-9059-x doi (NATIONALLICENCE)springer-10.1007/s10950-007-9059-x Mocquet Antoine Université de Nantes, Nantes Atlantique Universités, CNRS, Laboratoire de Planétologie et Géodynamique UMR 6112 UFR des Sciences et des Techniques, 2 rue de la Houssinière, BP 92208, 44322, Nantes Cedex 3, France aut Analysis and interpretation of the October 21, 1766 earthquake in the Southeastern Caribbean [Elektronische Daten] [Antoine Mocquet] The October 21, 1766 earthquake is the most widely felt event in the seismic history of Trinidad and Venezuela. Previous works diverged on the interpretation of the historical data available for this event. They associated the earthquake either with the Lesser Antilles subduction zone, with strike-slip motion along El Pilar fault, or with intraplate deformation at the edge of Guyana shield. Isoseismal areas are proposed after a new search and analysis of primary and secondary sources of historical information. Two of the largest earthquakes of the twentieth century which occurred in the region, the 1968 (M S 6.4, h = 103km), and the 1997 (M W 6.9, h = 25km) events, for which both intensity data and instrumentally determined source parameters are available, are used to calibrate the isoseismal areas and to interpret them in terms of source depth and magnitude. It is concluded that the large extent of intensity values higher than V is diagnostic of the depth (85 ± 20km) of the 1766 source, and of local amplifications of ground motion due to soft soil conditions and to strong contrasts of impedance at the edge of Guyana shield. It is proposed that the event occurred either in slab, or close to the bottom lithospheric interface between the Caribbean and South American plates (∼11°N; ∼62.5°W). The value of the magnitude is estimated at 6.5 < M S < 7.5 depending on the source depth and on the decay of ground motion as a function of distance. Deep and intermediate depth earthquakes can induce important casualties in Trinidad, Venezuela, and Guyana, possibly more damaging than those induced by shallower earthquakes along the strike of El Pilar Fault. Springer Science+Business Media B.V., 2007 Historical seismicity nationallicence Venezuela nationallicence Subduction nationallicence Intensity nationallicence Source depth nationallicence Local site effects nationallicence Journal of Seismology Springer Netherlands 11/4(2007-10-01), 381-403 1383-4649 11:4<381 2007 11 10950 https://doi.org/10.1007/s10950-007-9059-x text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s10950-007-9059-x text/html Onlinezugriff via DOI NATIONALLICENCE 100 1- Mocquet Antoine Université de Nantes, Nantes Atlantique Universités, CNRS, Laboratoire de Planétologie et Géodynamique UMR 6112 UFR des Sciences et des Techniques, 2 rue de la Houssinière, BP 92208, 44322, Nantes Cedex 3, France aut NATIONALLICENCE 773 0- Journal of Seismology Springer Netherlands 11/4(2007-10-01), 381-403 1383-4649 11:4<381 2007 11 10950 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer