Multiteide Project: Multiparametric characterization of the activity of Teide-Pico Viejo volcanic system

European Geosciences Union General Assembly (2017. Viena)Teide-Pico Viejo complex stands for one of the major natural volcanic hazards in the Canary Islands, due to the expected types of eruptions in the area and the high number of inhabitants in Tenerife Island. Therefore, it is necessary to have a volcanic alert system able to afford a precise assessment of the current state of the complex. For this purpose, the knowledge of the expected signals at each volcanic activity level is required. Moreover, the external effects that can affect the measurements shall be distinguished, external influences as the atmosphere are qualitatively known but have not been quantified yetCentro Geofísico de Canarias, Instituto Geográfico Nacional, EspañaObservatorio Geofísico Central, Instituto Geográfico Nacional, EspañaInstituto Geológico y Minero de España, EspañaLaboratoire GéoSciences Réunion, Institut de Physique du Globe de Paris, Centre National de la Recherche Scientifique, EspañaPeer reviewe

Magnetische Felder auf der ruhigen Sonne

Gegenstand dieser Doktorarbeit ist das Studium der Magnetischen Felder auf der "ruhigen Sonne". Diese Felder rhren von sehr kleinskaligen Bereichen auf der sonst "magnetfeldfreien" Sonnenoberfläche her und sind deshalb nur durch schwache Polarisationssignale gekennzeichnet. Während der letzten Jahre zog dieses Forschungsgebiet jedoch durch die Verfgübarkeit neuer, hochempfindlicher Instrumente zunehmende Aufmerksamkeit auf sich. Die vorliegende Arbeit nähert sich dem Thema aus zwei unterschiedlichen Richtungen, die von zwei neuartigen Beobachtungstechniken profitieren

Unveiling the pre-eruptive seismic series of the La Palma 2021 eruption: Insights through a fully automated analysis

9 pages, 5 figures, supplementary material https://doi.org/10.1016/j.jvolgeores.2023.107946.-- Data availability: Seismic and GNSS data used in this study are hosted at IGN data center. Some of the data is open access and for the remaining station data can be obtained upon request ([email protected]). The data generated in this study (PhaseNet+GaMMa events associated, NonLinLoc and HypoDD catalogs and La Palma 3D Velocity Model) and the configuration files can be found at https://doi.org/10.5281/zenodo.10017626, an open-source repository hosted at Zenodo (Díaz Suarez, 2023). All seismological software used in this work is open source. PhaseNet, GaMMA and HypoDD can be found at https://doi.org/10.5281/zenodo.7023970 (Zhu, 2022). NonLinLoc can be found on Anthony Lomax webpage (http://alomax.free.fr/nlloc/). GNSS data can be found on https://doi.org/10.5281/zenodo.6123266 (De Luca et al., 2022)We have analyzed the seismic series that preceded the La Palma 2021 eruption using a fully automated workflow based on Deep Learning. A new seismic catalog has been obtained that contains twice the number of events as the original manual catalog. The new catalog consists of 5059 absolute locations obtained using a non-linear location method and a 3D velocity model of the island, as well as relative locations by means of double differences method. Our enhanced catalog contains detailed features of seismic migration through the crust. We differentiate the sequence into three stages leading up to the eruption onset using independent seismic parameters: inter-event time variation coefficient, b-value spatial distribution, hypocentral migration and magnitude distribution. Our analysis identifies two magmatic intrusions: The first migrates from the center of the Cumbre Vieja area to the west coast of the island (stage 1), where it stagnates. After two days of seismic quiescence (stage 2), a second intrusion begins near the center of the island and rises to the surface leading to the eruption (stage 3). These results were further validated by GNSS observations and previous geodetic studies. Our findings highlight the usefulness of this type of automated methodology, offering a real-time and accurate response during intense seismic episodesA.V. acknowledges funding from the Severo Ochoa Center of Excellence accreditation CEX2019-000928-S to the Institute of Marine Sciences (ICM-CSIC). This research is funded by the Spanish Research Agency, project PID2020-114682RB-C32/AEI/10.13039/501100011033Peer reviewe

New insight into the 2011-2012 unrest and eruption of El Hierro Island (Canary Islands) based on integrated geophysical, geodetical and petrological data

A shallow water eruption started on October 10, 2011, ~2 km south off the coast of El Hierro (Canary Islands, Spain). The eruption lasted about five months and ended by early March 2012. Three months of unrest preceded this event with more than 10,000 localized earthquakes and up to 6 cm of vertical ground deformation. In the Canary Islands, this is the first eruption to be monitored by the network of Instituto Geográfico National (IGN) since the very beginning of the seismic unrest. This provided unprecedented time series that include geophysical (seismic and gravimetric), geodetic, geochemical and petrological data. In this work we discuss and interpret these data in order to describe the mechanisms of 2011-2012 El Hierro eruption, including ascent from magmatic source, a crustal storage, and the final intrusion in the South Rift before the eruption. Our research approach provides a multidisciplinary view of the dynamics of magma ascent and improves previous interpretations formulated during or shortly after the end of the eruption. According to our results, a major intrusion occurred beneath and around preexisting high-density magmatic bodies, localized at depth below the central part of the island. After a failed attempt to reach the surface through a low fractured zone located below the central-northern part of the island, the ascending magma finally found its way nearby the El Hierro South Rift Zone and erupted off the coast of La Restinga village, 350 m below sea level. The eruption was fed by the ascent of an important volume of material from the upper mantle that was emplaced near the crust-mantle boundary and progressively tapped during the eruption