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We present a research project intended to investigate the structure of Cumbre Vieja volcano in La Palma, Canary Islands, after the September-December 2021 Tajogaite eruption. Starting in the summer of 2023, we will deploy a dense network of 35 broadband seismometers provided by GFZ and University of Granada, that will add up to the ~20 permanent stations already in operation by the Spanish National Geographic Institute (IGN) and the Volcanological Institute of Canary Islands (INVOLCAN). In this way, we expect to obtain a dense coverage of the whole island with inter-station distances of about 5 km. This broadband network will be in operation for a period of about a year. Additionally, we will perform a series of large-N experiments using 200 geophones (provided by GFZ). First we will deploy these instruments along linear profiles across the island, in N-S and E-W directions. In a second stage, we will move the geophones to a bidimensional grid configuration centered at the eruption site. We estimate that inter-station distances will be of ~0.5 km in both cases, and the recording periods will span around 4-5 months per configuration. The data obtained from these deployments will be used to perform a dense receiver function analysis and ambient noise tomography to improve the knowledge of the shallow velocity structure of the volcanic rift around the eruption area down to a depth of a few km and to image the magma sources in the crust and uppermost mantle., The 28th IUGG General Assembly (IUGG2023) (Berlin 2023)

The 2021 Tajogaite eruption in La Palma, Canary Islands, was accompanied by strong volcanic tremor. In September 2021, during the first two weeks of eruption, we deployed two small-aperture seismic arrays. We chose two locations around Montaña Caldero and Llano del Jable, located about 4 km SE and 2 km NE of the eruption site. The arrays were composed of 1 three-component and 9 vertical-component short-period seismometers, sampled at 100 sps by a 12-channel data acquisition system. In each array, the receivers were spread with an aperture of about 400 m. Although they operated intermittently due to failures in the power supply related to ash fall, they provided long time series of multichannel seismic data that allow for the characterization of the syn-eruptive tremor. The analysis of the recorded wavefields reveals a persistent tremor source linked to the activity of the eruptive vents. The main component of the wavefield in the 1-3 Hz frequency band propagates with apparent slowness around 1 s/km, impinging on the arrays from directions of ~300 and 260ºN, respectively. These directions are slightly deviated from the active vents azimuths, a fact that we attribute to propagation effects produced by the topography and heterogeneous velocity structure. Subtle variations in the apparent slowness and propagation azimuths are investigated using the relative slowness estimate method, that allows for a precise determination of the apparent slowness vectors., The 28th IUGG General Assembly (IUGG2023) (Berlin 2023)

Deception Island (South Shetland Islands) is one of the most active volcanoes in Antarctica, with more than 15 explosive eruptive events registered over the past two centuries. Recent eruptions (1967, 1969 and 1970) and volcanic unrest episodes in 1992, 1999 and 2014–15 demonstrate that the occurrence of future volcanic activity is a valid and pressing concern for scientists, logistic personnel and tourists that are visiting or are working on or near the island. Over the last few decades, intense research activity has been carried out on Deception Island to decipher the origin and evolution of this very complex volcano. To that end, a solid integration of related scientific disciplines, such as tectonics, petrology, geochemistry, geophysics, geomorphology, remote sensing, glaciology, is required. A proper understanding of the island's evolution in the past, and its present state, is essential for improving the efficiency in interpreting monitoring data recorded during volcanic unrest periods and, hence, for future eruption forecasting. In this chapter, we briefly present Deception Island's most relevant tectonic, geomorphological, volcanological and magmatic features, as well as the results obtained from decades of monitoring the island's seismic activity and ground deformation., Plan research projects: CGL2007-28855-E, CTM2008- 03062-E, CTM2009-07705-E, CTM2009-08085-E, CTM2010- 11740-E, CTM2011-16049-E,CTM2014-57119-R, CTM2014-60451- C2-2-P, BRAVOSEIS (CTM2016-77315-R), CORSHET (POL2006- 08663), RECALDEC (CTM2009-05919-E/ANT), PEVOLDEC (CTM2011-13578-E/ANT), POSVOLDEC (CTM2016-79617-P) (AEI/FEDER, UE) and VOLGASDEC (PGC2018-095693-B-I00) (AEI/FEDER, UE). A. Geyer is grateful for her Ramón y Cajal contract (RYC-2012-11024). D. Pedrazzi is grateful for his Beatriu de Pinós (2016 BP 00086) and Juan de la Cierva (IJCI-2016-30482) contracts.

Deception Island (South Shetland Islands) is one of the most active volcanoes in Antarctica, with more than 15 explosive eruptive events registered over the past two centuries. Recent eruptions (1967, 1969 and 1970) and volcanic unrest episodes in 1992, 1999 and 2014–15 demonstrate that the occurrence of future volcanic activity is a valid and pressing concern for scientists, logistic personnel and tourists that are visiting or are working on or near the island. Over the last few decades, intense research activity has been carried out on Deception Island to decipher the origin and evolution of this very complex volcano. To that end, a solid integration of related scientific disciplines, such as tectonics, petrology, geochemistry, geophysics, geomorphology, remote sensing, glaciology, is required. A proper understanding of the island's evolution in the past, and its present state, is essential for improving the efficiency in interpreting monitoring data recorded during volcanic unrest periods and, hence, for future eruption forecasting. In this chapter, we briefly present Deception Island's most relevant tectonic, geomorphological, volcanological and magmatic features, as well as the results obtained from decades of monitoring the island's seismic activity and ground deformation.

The Bransfield Strait is a seismically active extensional rift located between the Antarctic Peninsula and the South Shetland Islands. The Strait is partly located on continental crust including areas within the transition to seafloor spreading. The amphibious seismic network BRAVOSEIS is an international effort focused on the seismological research of submarine volcanoes and rift dynamics in the Bransfield Strait. This network is the onshore component of the entire network consisting of 15 broadband land stations deployed in the South Shetland Islands and Antarctic Peninsula between January 2018 and February 2020. The offshore components (network code ZX) include 9 broadband ocean bottom seismometers (OBS) across the Central Bransfield Basin and a group of 6 hydrophone moorings spanning the rift area of 200 x 100 km2, with inter-station distance of ~30 km. Additionally, a smaller offshore array consisting of 15 short-period OBSs with an aperture of 20 km and a narrow inter-station distance of ~4 km was deployed around the Orca submarine volcanic edifice south of King George Island. The data will be used to study the geodynamics of the Bransfield Strait and the evolution of the incipient rifting zone in the domain where extension has been suggested. Seismological methods will include earthquake location, source mechanism, surface wave analysis with ambient noise and earthquake data, receiver function and shear wave splitting. The results may shed light on the crustal structure and tectonic regime in the region and image the location and extent of magma accumulations related to submarine volcanic structures. Finally, the results should provide clues to assess the internal processes that occur in the submarine volcanoes of the area undergoing rifting. Waveform data are available from the GEOFON data centre, under network code 5M and are embargoed until Mar 2024. Acknowledgments: We thank all participants in the BRAVOSEIS 2018, 2019, and 2020 cruises, with a special acknowledgement to Capt. Jose Emilio Regodon and his crew at R/V Hesperides; Capt. Juan Carlos Hernandez and his crew at Sarmiento de Gamboa; Miki Ojeda, Ezequiel Gonzalez, and all the UTM staff involved in the planification and realization of the surveys. We also thank the Spanish Polar Committee and institutions involved in the management of the Spanish Antarctic campaigns and the development of the Spanish Polar Program. We are grateful for the help and support that we always find in the personnel of the Antarctic Bases, especially the Spanish Bases Juan Carlos I and Gabriel de Castilla.

The present project is a joint effort between different institutions to deploy a dense seismic network at Gran Canaria island (Canary Islands, Spain). The interstation distance is around 20 km. The broadband seismic network is composed of one permanent (Guralp CMG-3T 120 s) and five temporary stations (Guralp CMG-3ESP 60 s). The permanent station is a 120 s Guralp CMG-3T and belongs to the Canary Island Seismic Network, run by the Instituto Geográfico Nacional (IGN) of Spain. The temporary stations are 60 s Guralp CMG-3ESP, provided by the GFZ seismic pool. The deployment was carried out in December 2009. The stations will be recording during two years. The improvement of the seismic network allow us to tackle the following issues: the detection and analysis of any local seismicity of tectonic and/or volcanic origin at Gran Canaria island; to contribute to the understanding of the regional seismicity with special interest in the oceanic channel between Tenerife and Gran Canaria Island in collaboration with a project running a dense temporary seismic network in Tenerife; to study the crustal and upper mantle structure, under Gran Canaria to constrain the crustal structure, the source of the volcanism, and better sample the mantle discontinuities and anisotropy. To study the Earth structure, we use receiver function analysis, ambient seismic noise and SKS anisotropy techniques, This project is part of a long-term research of the crustal and the mantle structure of the Canary Islands, which has started with Gran Canaria and Tenerife Islands and will eventually continue with the rest of the archipelago. The origin of the Canary Islands is generally attributed to a broad mantle upwelling under a slow moving plate, resulting in spatially and temporally distributed volcanic activity and a large number of seamounts and islands. A controversial discussion has been going on about the factors that control the evolution of the volcanic edifices, the type of the melting anomaly (a single, well defined mantle plume of a larger area of diffuse mantle upwelling), and the tectonic control of this evolution. This study is foreseen to provide important clues to understand the volcanic structure and tectonic evolution of the Gran Canaria Island.

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