Geodetic imaging of the magma ascent process during the 2021 Cumbre Vieja (La Palma, Canary Islands) eruption

<p>On the 11th of September of 2021, a seismic sequence began on La Palma (Canary Islands), followed by a rapid and significant ground deformation reaching more than 10 cm in the vertical component of the permanent GNSS station ARID (Aridane) operated by the Instituto Volcanol&#243;gico de Canarias (INVOLCAN). The pre-eruptive episode lasted only nine days and was characterized by an intense deformation in the western part of the island and intense seismicity with the upward migration of hypocenters. After the onset of the eruption, which occurred on the 19th of September of 2021, the deformation increased a few cm more, reaching a maximum on the 22nd of September and subsequently showing a nearly steady deflation trend in the following months.</p><p>We obtained a Sentinel-1 DInSAR dataset along both ascending and descending orbits, starting from the 27th of February of 2021 and the 13th of January of 2021, respectively. We selected the study area at the radial distance of 13 km from the eruption point (Latitude: 28.612; Longitude: -17.866) to realize an inverse model of the geometry of the causative sources of the observed ground deformation. While the ascending orbit that passed on the 18th of September indicated mainly a dike intrusion in the shallow depth, the descending orbit from the 20th of September seemed to indicate a deformation caused by at least two sources: the pre-eruptive intrusion and the nearly-vertical eruptive dike. The deeper source spatially coincides with the location of most of the pre-eruptive volcano-tectonic hypocenters.</p><p>Finally, based on the preliminary inverse model of the DInSAR dataset, we applied the geodetic imaging of D&#8217;Auria et al., (2015) to retrieve the time-varying spatial distribution of volumetric ground deformation sources. The final results show the kinematics of the upward dike propagation and magma ascent.</p><p>&#160;</p><p>References</p><p>D&#8217;Auria, L., Pepe, S., Castaldo, R., Giudicepietro, F., Macedonio, G., Ricciolino, P., ... & Zinno, I. (2015). Magma injection beneath the urban area of Naples: a new mechanism for the 2012&#8211;2013 volcanic unrest at Campi Flegrei caldera. Scientific reports, 5(1), 1-11.</p>