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Seismic catalogues of the 2018-2019 volcano-seismic crisis offshore Mayotte, Comoro Islands

In May 2018 a volcano-seismic sequence accompanied the upward migration of a magmatic intrusion from Moho depth to the seafloor led to the drainage of the deep magmatic reservoir and to the birth of a submarine volcano offshore the island of Mayotte, Comoro Islands. This process of magma transport was accompanied by an intense seismic swarm and peculiar long-duration very long period signals. Between 1 January 2018 and 1 May 2019 we detected 407 sources of very long period signals and 6990 volcano-tectonic earthquakes. This report collects detection, location and source parameters catalogs for these two sets of earthquake sources.This data publication provides the catalogues of very long period (VLP) signals and volcano-tectonic (VT) earthquakes, as discussed in Cesca et al. (2019). Here, methods and data used to create the different catalogues are only briefly discussed; a more accurate description is given in Cesca et al. (2019), which furthermore discusses the different processes of dike migration, undersea eruption, deep reservoir drainage and overburden sagging which are responsible for the seismic activity.

Cathodoluminescence zoning images of Lower El Cajete quartz and sanidine crystals, Valles Caldera, New Mexico, USA

The Valles Caldera, New Mexico, USA was created by two caldera-forming eruptions at ~1.6 and ~1.1 Myr. Since then, post-caldera activity has consisted of lava domes, lava flows, large explosive phases, and a hydrothermal system active today. Possibly the youngest eruption sequence, El Cajete, was emplaced 74.4 ± 1.3 ka (Zimmerer et al., 2016) and began with pyroclastic surges, followed by pyroclastic density currents (PDCs) and pumice-rich Plinian pyroclastic fall (Self et al., 1988). The objective of this project was to characterize crystal grains from the early El Cajete sequence, in terms of morphology and textures, using scanning electron microscopy (SEM). The early El Cajete differs from the later part of the sequence in its greater stratigraphic and lithologic complexity, having been formed from not only pyroclastic fall (like the later El Cajete) but also surge beds and PDCs. This dataset was collected under the national open access action at Istituto Nazionale di Geofisica e Vulcanologia, Sezione di Pisa SEM/EDS facility supported by WP3 ILGE – MEET project, PNRR – EU Next Generation Europe program, MUR grant number D53C22001400005. This allowed me to obtain the present dataset of 31 cathodoluminescence (CL) images of 30 quartz crystals and one sanidine crystal.

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