Apports de la croissance des coraux à l'étude sismo-tectonique de Futuna (territoire de Wallis et

BA S6b 614 O 1999 Académie des sciences / Éditions scientifiques et médicales SAS. Tous droits reservés. e7 d""' #. 4_;b Tectonique / Tectonics 1 SslZd 254 aO 3 3 - Apports de la croissance des coraux à I'étude sismo-tectonique de Futuna (territoire de Wallis et Futuna, Pacifique Sud-Ouest) Data provided by coral growth for sismoteclonic studies in Futma (French Overseas Territoly of Wallis and Futuna, sozitlxuest Pacijk) Guy Cabioch, Sté hane Calmant, Robert Pillet, Bernard Pelletier, Marc Régnier, Pierre Lebellegar 8 Laboratoire de géologie et géophysique, UMR (( Geosciences Azur )) 6526, centre IRD de Nouméa, BP A5,98848 Nouméa cedex, Nouvelle-Calédonie ' 1 (Reçu le 5 avril 1999, accepté après révision le 19 juillet 1999) Abstract - The iiiorpliology ancl growth analysis of coral microatolls using X-rays indicates that a subsidence of 3 ciii from 1977 to 1993, an uplift of 5 ciii occurred in 1993 in the southeast of after Futuna (southwest Pacific). These vertical niotions are related to the strain accumulation followed by their relaxation during the earthquake (Mw: 6.4) on 12 March 1993. The locations published by the global network are not in agreement with tlie aftershocks recorded locally and the Co-seismic uplifts obseived on the reefs. The latter indicate instead that the rupture area is located below the southwest of Futuna at an average depth of S km. (O 1977 Académie des sciences / Éditions scientifiques et méclicales Elsevier SAS.) ...