Day 4

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Paper title Advanced multi-temporal InSAR technique reveals potential precursory ground deformation prior to the 2021 La Palma eruption
  1. Roberto Montalti TRE-Altamira, Barcelona, Spain Speaker
  2. Isora Brito del Castillo TRE-Altamira, Barcelona, Spain
  3. Javier García Robles TRE-Altamira, Barcelona, Spain
  4. Federico di Traglia National Institute of Oceanography and Applied Geophysics
Form of presentation Poster
  • D1. Managing Risks
    • D1.01 Satellite EO for Geohazard Risks
Abstract text In the last decades, satellite remote sensing played a key role in Earth Observation, as an effective monitoring tool applied to Geo-hazards identification and mitigation, in a global observation framework. Space-borne SAR data and, in particular, the differential Interferometry (InSAR) technique, are very useful for the analysis of long-term or co-seismic crustal movements, for the identification of landslides and subsidence, as well as for determining the current state of magmatic/volcanic systems. Ground displacements can be better estimated by processing a long stack of images using multitemporal InSAR algorithms such as the SqueeSAR, which represents the most advanced technique for ground deformation analysis. In volcanology, considering the difficulties to carry out in situ analysis and the hazard phenomena acting over wide spatial and temporal scales, SqueeSAR® can provide incomparable information on unrest, co-eruptive deformation, and flank motion. Interferometry is also a powerful tool to monitor the evolution of the deformation in a wide-scale range during the eruption days and predict the volcan behavior.
In this work, ground deformation data, derived from Sentinel-1 constellation dataset by means of the SqueeSAR® algorithm, was carried out over the Cumbre Vieja volcano, located in the western part of La Palma Island, in the Canary archipelago. The volcano erupted on 19 September 2021, after a seismic swarm. The ongoing eruption formed a complex cinder cone produced by fire fountain activity, and fed several lava flows affecting over 1000 hectares, that are devastating and burying hundreds of buildings and properties, causing high direct and indirect economic losses.
The final goal is to understand if it is possible to identify signals related to the rise of magma inside the volcanic building, and therefore to define precursor signals to the eruptive activity. Complementary, Classical DInSAR allowed to determine the massive deformation triggered in the eruptive episode, reaching in 6 days more than 30 cm in the Line-Of-Sight of the satellite (LOS) in the area close to the fissure vents.
Analyzing the deformations of the volcano in the year preceding the eruption, the results of the analyzes carried out, allow us to assert that the ground displacements can be considered precursors of the eruption, both in the long and in the short term, allowing to identify the phases of magmatic ascent, up to the opening of the eruptive vent.