A year of lava fountaining at Etna: Volumes from SEVIRI

International audienceWe present a new method that uses cooling curves, apparent in high temporal resolution thermal data acquired by geostationary sensors, to estimate erupted volumes and mean output rates during short lava fountaining events. The 15 minute temporal resolution of the data allows phases of waxing and peak activity to be identified during short (150-to-810 minute-long) events. Cooling curves, which decay over 8-to-21 hour-periods following the fountaining event, can also be identified. Application to 19 fountaining events recorded at Etna by MSG's SEVIRI sensor between 10 January 2011 and 9 January 2012, yields a total erupted dense rock lava volume of ∼28 × 106 m3, with a maximum intensity of 227 m3 s−1being obtained for the 12 August 2011 event. The time-averaged output over the year was 0.9 m3 s−1, this being the same as the rate that has characterized Etna's effusive activity for the last 40 years

APPORT DES DONNEES SAR A LA COMPREHENSION ET A LA SURVEILLANCE DES VOLCANS : EXEMPLE DU PITON DE LA FOURNAISE

International audienceLast two decades have proven that remote sensing represents a key tool to improve our knowledge of volcanic systems but also to monitor active volcanoes. Based on the specific case of Piton de la Fournaise, Reunion Island, the most active French volcanoes, we here illustrate how Synthetic Aperture Radar (SAR) data, providing information even in cloudy conditions, make it possible to map eruptive deposits, to quantify their volumes but also to estimate the volcanoes topography (with metric precision) as well as surface deformation fields (with a precision reaching a few millimeters).La télédétection s'est révélée au cours des deux dernières décennies comme un outil essentiel à la fois pour améliorer notre connaissance des systèmes volcaniques mais également pour assurer la surveillance des volcans actifs. En utilisant l'exemple du Piton de la Fournaise, le plus actif des volcans français, nous illustrons ici comment les données radar satellitaires (SAR), dont l'utilisation n'est pas empêchée par la présence de nuages, permettent non seulement de cartographier les dépôts éruptifs et d'estimer leur volume mais aussi de mesurer la topographie de l'édifice volcanique (avec une précision métrique) ainsi que ses déformations de surface (avec une précision atteignant quelques millimètres)