Submarine morphology of the Comoros volcanic archipelago

Gas Geochemistry at Grande Comore and Mayotte Volcanic Islands (Comoros Archipelago), Indian Ocean

“…b) the reactivation of regional lithospheric structures, which interact with asthenospheric processes. This hypothesis rejects the previous model because it is inconsistent with the current volcanic activity which includes both Karthala volcano and the recent and still ongoing submarine volcanic activity eastward of Mayotte and with the absence of a clear age decrease along the archipelago (Famin et al, 2020;Lemoine et al, 2020;Michon, 2016;Nougier et al, 1986;Tzevahirtzian et al, 2021) At Mayotte, the volcanic activity becomes increasingly older from the eastern side (Petite Terre island), to the western main island (Grande Terre) (Nehlig et al, 2013). The still ongoing (at the time of writing), large-volume and long-lasting sub-marine eruption of Mayotte, the largest submarine event ever detected by monitoring networks (Cesca et al, 2020;Lemoine et al, 2020), challenges current models on the origin of Comoros volcanism.…”

“…While rift zones are marked by well defined alignments of volcanic cones in Grande Comore, they are much less defined in Mayotte, where a set of mafic scoria cones and phonolite maars are scattered on the Petite Terre island (Famin et al., 2020; Michon, 2016; Nehlig et al., 2013; Tzevahirtzian et al., 2021). In Grande Comore, volcano flanks are often resurfaced by the frequent emplacement of lava flows, nevertheless thick soils and sand covers are found in most locations, suitable for the measurement of soil CO 2 fluxes.…”

“…The recent review of morphological, geological and chronological data of Tzevahirtzian et al. (2021) suggests that Mayotte and Moheli are the oldest islands, while Anjouan and Grande Comore are the most recent ones. The recent volcanism of Karthala in Grande Comore has been interpreted as hot spot related by geochemical studies (e.g., Class et al., 1998).…”

Risk communication successes and limits during sismo-volcanic crisis: the example of Mayotte, France

“…Hereafter, we are citing scientific bulletins and websites as references (including their URL when existing) while authorities' press releases are given in the supplementary dataset (ministerial press releases as well as those from the Préfecture of Mayotte). We also included the academic papers published during our 3 years period of study (Cesca et al, 2020;Famin et al, 2020;Feuillet et al, 2021;Lemoine et al, 2020;Tzevahirtzian et al, 2021). We coded this dataset by date of publication and by publishing institution/author, and quantitatively analysed it to show the time evolution of the publication rate by the different actors of the risk management (see Figure 4).…”

“…We do not count the numerous automatic bulletins emitted by REVOSIMA (daily automatic bulletin are emitted since march 2020), BCSF-RéNass and EMSC but we count the report published by the BCSF-RéNass's Groupe d'intervention macrosismique (GIM) and a web article from the EMSC that aims at providing a global view of the seismic crisis. We include in our database the five academic papers (one is a preprint version of a submitted paper) dedicated to the crisis that were published during our period of study (Cesca et al, 2020;Famin et al, 2020;Feuillet et al, 2021;Lemoine et al, 2020;Tzevahirtzian et al, 2021) and commented by the press and/or the members of STTM facebook group.…”