Long-lasting families of similar events at Cotopaxi volcano between 2013 and 2018

Autor: Battaglia, Jean, Hidalgo, Silvana, Helmstetter, A., Cordova, J., Vasconez, J., Almeida, M., Telenchana, E.
Přispěvatelé: Laboratoire Magmas et Volcans (LMV), Institut national des sciences de l'Univers (INSU - CNRS)-Université Jean Monnet [Saint-Étienne] (UJM)-Institut de Recherche pour le Développement et la société-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Centre National de la Recherche Scientifique (CNRS)-Observatoire de Physique du Globe de Clermont-Ferrand (OPGC), Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Institut national des sciences de l'Univers (INSU - CNRS), instituto Geofísico, Escuela Politécnica Nacional (EPN), Institut des Sciences de la Terre (ISTerre), Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Institut national des sciences de l'Univers (INSU - CNRS)-Université Jean Monnet - Saint-Étienne (UJM)-Institut de Recherche pour le Développement et la société-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Centre National de la Recherche Scientifique (CNRS)-Observatoire de Physique du Globe de Clermont-Ferrand (OPGC), Institut national des sciences de l'Univers (INSU - CNRS)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Centre National de la Recherche Scientifique (CNRS), Jouhannel, Sylvaine
Jazyk: angličtina
Rok vydání: 2019
Předmět:
Zdroj: 8ème Symposium sur la géodynamiue des Andes (ISAG)
8ème Symposium sur la géodynamiue des Andes (ISAG), Sep 2019, Quito, Ecuador
Popis: International audience; Cotopaxi volcano (5,897 m), located in Central Ecuador, is covered by a glacier down to about 5000 m elevation. Its last eruption occurred in 2015. The volcano is monitored by the Instituto Geofísico, whose monitoring networks include a seismic station (BREF) located 1 km below the summit, 400 m from the base of the glacier. Additionally, from April to September 2018, we operated at the base of the glacier a seismic antenna of 7 broadband stations.We examined data from station BREF, recorded between January 2013 and October 2018, with the aim of identifying families of similar events. We applied a 3-step procedure: (1) automatic detection of events, (2) classification into families and (3) re-composition of their temporal evolution using matched-filtering. This procedure outlines several families related to the 2015 eruption. More strikingly it outlines the presence of numerous families which may persist for years. To locate events belonging to several of these families active during the installation of the seismic antenna, we applied a method based on inter-station waveform cross-correlation. Preliminary results indicate locations on the glacier, near the surface, suggesting that all the largest long-lasting families active in 2018 correspond to Ice Quakes. These may be due to cracking of the icecap, basal slip or forced water flow within the glacier.Additionally, the temporal evolution of the families during the 5 years of our study outlines a striking feature. While most of these families active in 2013-2015 persisted throughout the 2015 eruption, all of them have been interrupted by the large (Mw=7.8) subduction earthquake which occurred near Pedernales on April 16, 2016, 250 km from the volcano. A comparison of pre- and post- April 16 waveforms shows that the M=7.8 event induced changes in the coda of the waveforms. Our results suggest that the distal subduction earthquake had a stronger influence on the glacier or its shallow substratum than the 2015 eruption
Databáze: OpenAIRE
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