In April 2018, lithospheric magma reactivation initiated a seismo volcanic crisis along with the birth of a new submarine volcano, 50 kms to the east of Mayotte. Repeated oceanographic cruises revealed intensive volcanic activiy that is still ongoing 14kms offshore ( e.g. N. Feuillet et al., 2021, Nature Geosci., https://doi.org/10.1038/s41561-021-00809-x). In this area, very recent undated voluminous lava flows have been mapped, suggesting a potential for caldera reactivation and tsunamigenic collapse due to voluminous magma withdrawal.
The observatory system we propose for Mayotte (Activity 5) will allow the detection and characterization of low magnitude seismicity, the measurement of seafloor deformation and the direct observation of submarine hydrothermal and volcanic degassing plumes. This will provide direct, real-time information to track the transitory short-timescale dynamics governing the processes that might be precursory to new eruptive activity, caldera formation and gravitational instability.