A better understanding of climate and the workings of major subduction faults thanks to corals
Coral microatolls are massive corals living in the intertidal zone (area within the tidal range). Already studied in the Pacific and Indian oceans, the microatoll tool has enabled us to advance our understanding of the climate and functioning of major subduction faults.
Panorama of the Belloc microatolls site in Haiti after the earthquake of January 12th, 2010
Publication date: 13/04/2016
Press, Research
Related teams :
Marine Geosciences
Related themes : Earth System Science
These corals have a flattened shape with a living crown surrounding a dead central part. This characteristic shape reflects the fact that coral growth is controlled by relative fluctuations in sea level.
The discovery of coral microatolls in the West Indies has led to a proposal to study these massive corals, which are likened to natural tide gauges. The study of microatolls in Haiti has made it possible to precisely quantify the uplift associated with the destructive earthquake of January 12th 2010.
The stratigraphic analysis of coral slices over a period of one hundred years has provided valuable information on the relative fluctuations in sea level in the region, as well as on the natural variability of these corals, the record of which is not identical from one coral to another.
Along the Caribbean arc, the study of microatolls in Martinique has enabled us to reconstruct relative fluctuations in sea level since 1800. We have shown that the island has been sinking progressively since that period as a result of deep earthquakes, loading of the subduction interface during interseismic periods (between two earthquakes) and the global rise in sea level.
Réf:
- Two hundred thirty years of relative sea level changes due to climate and megathrust tectonics recorded in coral microatolls of Martinique (French West Indies), Weil-Accardo, Jennifer and Feuillet, Nathalie and Jacques, Eric and Deschamps, Pierre and Beauducel, Francois and Cabioch, Guy and Tapponnier, Paul and Saurel, Jean-Marie and Galetzka, John, Journal of Geophysical Research: Solid Earth, 2016
- Relative sea-level changes during the last century recorded by coral microatolls in Belloc, Haiti, Weil-Accardo, J and Feuillet, N and Jacques, E and Deschamps, P and Saurel, J-M and Thirumalai, K and Demeza, S and Anglade, D, Global and Planetary Change, Vol 139,pp1–14, 2016 DOI:10.1016/j.gloplacha.2015.12.019
