Horizon 1 1 17 ACL : Articles dans des revues avec comité de lecture répertoriées par l'AERES Marine Geology 107116 [19 ] Tsunami deposits Paleotsunami New Caledonia Loyalty Islands Melanesia Pacific Islands NOUVELLE CALEDONIE PACIFIQUE ILES 2023 fdi:010090259 ENG Marine Geology 0025-3227 ISI:001071145500001 10.1016/j.margeo.2023.107116 https://www.documentation.ird.fr/hor/fdi:010090259 https://www.documentation.ird.fr/intranet/publi/2023-11/010090259.pdf 463 Horizon (IRD) This study aims to identify tsunamis in the coastal sedimentary archives of New Caledonia (Grande Terre and the Loyalty Islands) in the southwest Pacific, to extend a relatively short historical tsunami record (150 years), and to bring more constraints on the frequency of the main tsunamigenic earthquakes in the region. Using a combination of sedimentary and geochemical approaches on sediment core samples, we document three types of deposits related to marine inundation: (1) bioclastic sand layers; (2) crypto-deposits with a marine chemical signature; and (3) accumulations of rounded pumice lapilli. Most of the sampling sites being located outside the morpho-dynamic impact zone of the cyclones, a tsunami origin is preferred. The spatial distribution of the deposits suggests tsunami runups exceeding 2.5 m a.s.l. on the northeastern coast of Grande Terre, 6 m on the eastern coast of Maré Island, and 10 m on the northeastern coast of Lifou Island. Finally, at least six tsunamis were preserved in the sedimentary record: one event soon after 1000 BCE, two events during the first millennium CE, and at least three events during the last millenium (including a 15th century tsunami, the 28 March 1875 tsunami, and a tsunami possibly related to the 1729 earthquake in Vanuatu). 064 ; 032 UR163 / UR082