Earthquakes and volcanoes in Mayotte: conclusions of the second oceanographic campaign
A scientific team took part in a second oceanographic campaign entitled "MAYOBS2", from June 11th to 17th, 2019.
Publication date: 27/06/2019
Observatories, Press, Research
Related observatories : Volcanological and Seismological Monitoring Network of Mayotte (REVOSIMA)
Related themes : Natural Hazards
As part of a research program funded by the Ministry of Higher Education, Research and Innovation, the Ministry of Ecological Transition and Solidarity, the Ministry of the Interior, the Ministry of Overseas France and the scientific institutes involved (IPGP, IPGS, BRGM, IFREMER), several researchers took part in a second oceanographic campaign entitled “MAYOBS2”, from June 11th to 17th, 2019.
Under the responsibility of Stephan Jorry from IFREMER, the scientists on board were:
- IPGP: Romuald Daniel (IPGP/CNRS), Félix Leger, Eric Jacques, Philippe Kowalski (IPGP/CNRS), Anne Le Friant (IPGP/CNRS), Manon Bickert, Gaëlle Benatre
- BRGM: Anne Lemoine, Fabien Paquet
- IFREMER: Chastity Aiken, Sylvain Bermell, Charline Guérin, Pierre Guyavarch, Pascal Pelleau
The aim of this new mission was to continue acquiring data following the recent discoveries made during the MAYOBS1 mission, in particular by recovering and redeploying the seabed seismometers (OBS), carrying out new bathymetry and measuring reflectivity in the areas mapped during MAYOBS1 (from May 6th to 18th 2019), with the aim of detecting possible changes in the submarine relief.
These data were supplemented by rock samples and observations of fluid outflows in the area of the volcano and the swarm.
Analysis of the seismic data carried out on board confirms that the earthquakes are still relatively deep (between 25 and 50km below the surface), with the main swarm confirmed to be around 10km to the east of Petite-Terre. The OBSs were redeployed at the end of the mission, with the exception of one OBS that had a data recording problem and needs to be repaired on land before being put back in the water.
Bathymetric surveys carried out above the new volcano showed that its size had not changed since the MAYOBS 1 campaign a month ago. In addition, a new landform has been identified to the south of the volcano. This new zone of volcanic activity covers an area of more than 8 km² and its height varies between 25 and 75 metres (Figures A, B, C and D).
In both the main swarm and the volcano area, the new surveys have confirmed the presence of plumes visible in the water columns but not reaching the surface.
