HR: 09:15h
AN: V31A-06    [Abstracts]
TI: Causal link between Quaternary paleoclimatic changes and flank collapses on volcanic islands
AU: * Hildenbrand, A
EM: anthony.hildenbrand@u-psud.fr
AF: Laboratoire IDES, UMR 8148 CNRS-UPS, Departement des Sciences de la Terre, University Paris Sud 11, Batiment 504, Orsay, 91405, France
AU: Quidelleur, X
EM: xavier.quidelleur@u-psud.fr
AF: Laboratoire IDES, UMR 8148 CNRS-UPS, Departement des Sciences de la Terre, University Paris Sud 11, Batiment 504, Orsay, 91405, France
AU: Samper, A
AF: Laboratoire IDES, UMR 8148 CNRS-UPS, Departement des Sciences de la Terre, University Paris Sud 11, Batiment 504, Orsay, 91405, France
AB: Giant landslides and resulting tsunamis represent the main geologic hazards linked to volcanic island evolution. From bathymetric data and on-land geological studies, flank failures have been identified around numerous volcanic islands, in most geodynamic contexts. However, the enabling and triggering conditions are still poorly understood and several internal and external causes may act simultaneously to reach a critical threshold. We here present a compilation of well-dated flank destabilization events within the last 1 Myr from Tahiti, Hawaii, Canary Islands, Guadeloupe and Martinique (Lesser Antilles), and examine their relationships with global paleoclimatic changes evidenced by a global stack of benthic ?18O records. We show that a causal relationship between flank collapse of volcanic islands and global climatic changes has existed at least since 900 kyr. Moreover, high precision ages reported here favor the hypothesis that major flank collapse events occurred during the onset of glacial to interglacial transitions when a sudden influx of melt water from polar ice caps causes rapid sea level rise. We propose that following a sub aerial erosion interval during low sea level stands, rapid sea level rise induces enhanced coastal erosion and sudden changes of pore pressure conditions within basal layers, which favor edifice failure.
DE: 1105 Quaternary geochronology
DE: 1641 Sea level change (1222, 1225, 4556)
DE: 8408 Volcano/climate interactions (1605, 3309)
DE: 8488 Volcanic hazards and risks
DE: 8499 General or miscellaneous
SC: Volcanology, Geochemistry, and Petrology [V]
MN: 2007 Joint Assembly