Disdrometer measurements of tephra fallout from the Tajogaite 2021 eruption (La Palma island, Spain)
Franck Donnadieu1,2, Valentin Freret-Lorgeril1,2, Thierry Latchimy2, Clothilde Biensan1, Jade de Paoli1, Louis Tyrode1
Affiliations: 1Université Clermont Auvergne, CNRS, IRD, OPGC, Laboratoire Magmas et Volcans, F-63000 Clermont-Ferrand, France; 2Université Clermont-Auvergne, CNRS, UAR 833, OPGC, F-63177 Aubière, France
Presentation type: Poster
Presentation time: Tuesday 16:30 - 18:30, Room Poster Hall
Poster Board Number: 114
Programme No: 3.15.19
Abstract
Tajogaite volcano erupted during three months in late 2021 constructing a new scoria cone, and generating destructive lava flows and sustained ash plumes with impactful tephra fallout on La Palma Island (buried houses, roof collapse, traffic interruption, respiratory and ocular discomfort etc). This long-lasting eruption displayed activity fluctuations and transitions at short time scale, with challenging risk assessment and crisis management. In this context, we carried out a field experiment supported by the EUROVOLC project in order to test the application of optical disdrometers for measuring tephra sedimentation and grain size associated with pulsatory activity and to evaluate their potential for operational monitoring during explosive eruptions. Disdrometers powered by batteries and solar panels were deployed in the field to record particle size distributions and terminal fall velocities of ash and lapilli particles. We used a modified Parsivel2 (OTT, acquiring at 5 s) and a Laser Precipitation Monitor (LPM Thies, measuring individual particles) along with simultaneous ash samples from ground collectors. Both disdrometers were first colocated at <1 km SW from the plume emission vent(s); the LPM sensor was later moved toward SW by 260 m in order to synchronously record more distal fallout. Recorded time series, sedimentation rates, and physical characterization of ash are presented.