COmoros & maYotte: vOlcanism, TEctonics and Seismicity – COYOTES
COYOTES (Comoros & maYotte: vOlcanism, Tectonics and Seismicity)
To understand the unprecedented telluric event of the Mayotte seismo-volcanic crisis, it appears essential to reach a critical level of knowledge on the evolution of the seismic, volcanic and geodetic deformation, but also on the geodynamic context, including the kinematics and the characterization of the lithospheric and crustal structures, including both short and long-term and regional and local scales. The results would allow to assess better the volcanic and seismic hazards of the area.
Regional geodynamic context of the North Mozambique channel, distribution of the deformations, the tectono-sedimentary evolution and the role of the inheritance to better assess the hazards and risks
The COYOTES project aims to better understand the regional geodynamic and geological context of the northern Mozambique channel. The main objectives are to understand the distribution of active and recent deformations (sliding, faults, volcanoes, uplifting, vertical motions,..) around the Comoros Archipelago including the Mayotte Island, to image the crustal structuration and to study the recent tectono-sedimentary evolution. These results will give some information on the role of inheritance in the spatial distribution of present-day deformation, linked to the Mayotte seismo-volcanic crisis.
Main marine geophysical (bathymetry, Seismic, magnetism, gravimetry) and geological (dredging, coring) data sets have been acquired during the earlier oceanographic campaigns (BATHYMAY (2004), MAYOBS (2019-2020), SHOM, ...) at the scale of Mayotte or will be acquired during the SISMAORE campaign (scheduled in 2020-2021) at the regional scale. Seismological data is acquired by the international network and local permanent stations at land and sea (OBS network, SISMAYOTTE, MAYOBS, REVOSIMA).
The COYOTES project plans to conduct integrated multi-thematic and multidisciplinary studies from these collected data. These studies will be carried out within the framework of three theses, a post-doc and some masters supervised by experts in various field and those already involved in ongoing studies.
This project is organized in four main work-packages:
•WP1-Current seismic sequence, deformation and kinematics;
•WP2-Recent and active volcanism and tectonics in the Comoros archipelago;
•WP3-Long-term geodynamics: Regional structuration and inheritance;
•WP4-Animation, Impact and Dissemination.
(cf. for details see the COYOTES webportal)
This project will help to improve the geological knowledge of this region, little studied until then (seismicity, deformation, causes of the seismic swarm, geodynamics, tectonics, volcanism, geology of the crust and the sedimentary cover, hydrothermal fluids, mineral resources …). Mayotte sismovolcanic crisis is a natural laboratory regarding some scientific concepts.
The results of COYOTES will be used to assess the volcanic and seismic hazards in the North Mozambique area, in particular Mayotte.
The partners of this project are committed to promote the results through dissemination of international scientific publications in open access and participations in congress.
At the end of the COYOTES project, we plan to communicate also through educational material including public seminars regarding the origin and implication of the seismic sequence.
The data will be archived in the national databases and searchable online.
A special effort will be dedicated to transfer our results for supporting future seismic hazard studies.
Since May 2018, a very active seismic sequence is affecting the area of Mayotte (Comoros volcanic archipelago). Long lasting low frequency tremors and rapid and continuous eastward drifting and subsidence of Mayotte have also been recorded. The scale of this event, its duration, its seismic signature and the induced surface deformations suggest the exceptional nature of this telluric phenomenon, never quantitatively observed before. Preliminary studies suggest magmatic origin for this event.
The lack of geological and geodynamical knowledge don’t allow a full understanding of both the causes and consequences of the Mayotte Seismic Sequence. Therefore, it precludes satisfactory assessment of natural hazards. Several recent actions just started the collection of additional seismological, geodesic, geophysical and geological data in order to better characterize this current seismic event.
This COYOTES project will allow the federation of experts into a collaborative team including three PhD thesis and a post-doc researcher. It plans to conduct integrated multi-thematic and multidisciplinary studies from the recently collected data and to acquire new relevant data, gathering experts in the various fields and those already involved in ongoing studies. Main objectives of this project are to understand the Mayotte Seismic Sequence and better define the geological and geodynamic context unknown so far. The project will integrate new onshore and offshore acquisitions of geological and geophysical data, their interpretation as well as modelling phases. The tasks concern the current seismic sequence, deformation and kinematics, the recent and active volcanism and tectonics in the Comoros archipelago, the regional structuration and inheritance and finally, the scientific and public dissemination.The results on the understanding of the seismic sequence as well as the local and regional volcano-tectonic context, resulting from this project, will be translated in terms of hazards and geological synthesis.
Madame Isabelle Thinon (BUREAU DE RECHERCHES GEOLOGIQUES ET MINIERES)
The author of this summary is the project coordinator, who is responsible for the content of this summary. The ANR declines any responsibility as for its contents.
IPGP Institut de physique du globe de Paris
BRGM BUREAU DE RECHERCHES GEOLOGIQUES ET MINIERES
IPGS Institut de Physique du Globe de Strasbourg (UMR 7516)
ISTEP Institut des sciences de la Terre Paris
Help of the ANR 645,068 euros
Beginning and duration of the scientific project: March 2020 - 48 Months