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Report (in spanish) of the 2021-22 field campaign in Livingston and Deception islands, Antarctica for the maintanance of the TSP and CALM permafrost and active layer monitoring stations of PERMATHERMAL network from Alcalá University (Universidad de Alcalá, UAH), Spain. This report includes anshort description of thehistory of the monitoring network, a description of the instruments and their location, and an overview of the data acquired in 2021 years by the different instruments, as well asproposals of future actions and tasks to ensure the continuity of the this time serie. This report is a deliverable to the funding agency: Unit of Marine Technology of the Spanish Council for Scientific Research, Government of Spain, by thecontract withreference2022/042 and code 2022/00102/001 with Universidad de Alcalá.

Report (in spanish) of the 2020-21 field campaign in Livingston and Deception islands, Antarctica for the maintanance of the TSP and CALM permafrost and active layer monitoring stations of PERMATHERMAL network from Alcalá University, Spain. This report includes anshort description of thehistory of the monitoring network, a description of the instruments and their location, and an overview of the data acquired in 2020 years by the different instruments, as well asproposals of future actions and tasks to ensure the continuity of the this time serie. This report is a deliverable to the funding agency: Unit of Marine Technology of the Spanish Council for Scientific Research, Government of Spain, by thecontract withreference141/2021 and code 2020/00553/001 with Universidad de Alcalá.

[EN] Deception Island is an active volcano on which two Antarctic bases are located, the Spanish Antarctic Base Gabriel de Castilla and the Deception Antarctic Base, with scientific personnel working there during the summer (December-March). To ensure the safety of these personnel, it is necessary to monitor volcanic and seismic activity continuously with different technologies. Among the technologies that can be used are Differential Synthetic Aperture Radar Interferometry (DInSAR) techniques for ground motion detection. Ground motions can have different origins, including volcanic and seismic movements. In this research we are going to analyse the movements that have occurred throughout 2018, 2019 and 2020, detected using DInSAR techniques and we will try to discriminate their origin. The detection using DInSAR techniques has been carried out with images acquired by the Sentinel 1A and Sentinel 1B satellites during the months of December to March 2018, 2019 and 2020. DInSAR techniques with image pairs have been used. Of all the possible combinations of image pairs, those with the greatest a priori possibilities were selected. Once the image pairs were selected, they were processed using the SNAP (Sentinel Application Platform) and SNAPHU (Statistical-Cost Network-Flow Algorithm for Phase Unwrapping) applications. Once the deformation maps had been obtained, the movements were analysed together with other data on the island such as topographic, geological, geomorphological, slope and orientation maps to find an explanation for each of the movements detected and to classify them according to their type of origin., [ES] La isla Decepción es un volcán activo en el cual se localizan dos bases antárticas, la Base Antártica Española Gabriel de Castilla (BAEGC) y la Base Antártica Argentina (BAA), con personal científico que desarrolla su labor durante el verano (diciembre-marzo). Para garantizar la seguridad de dicho personal es necesario monitorizar la actividad volcánica y sísmica de manera continua con distintas tecnologías. Entre las tecnologías que se pueden utilizar se encuentran las técnicas de Interferometría Diferencial SAR (DInSAR) para la detección de movimientos del terreno. Los movimientos en el terreno pueden tener distintos orígenes entre los cuales se encuentran los volcánicos y sísmicos. En esta investigación se van a analizar los movimientos que se han producido a lo largo de los años 2018, 2019 y 2020, detectados mediante técnicas DInSAR y se intentará discriminar su origen. La detección mediante técnicas DInSAR se ha realizado con imágenes adquiridas por los satélites Sentinel 1A y Sentinel 1B durante los meses de diciembre a marzo de los años 2018, 2019 y 2020. Se han utilizado técnicas DInSAR básicas con pares de imágenes. De todas las posibles combinaciones de pares de imágenes se han seleccionado las que tenían mayores posibilidades a priori. Una vez seleccionadas las parejas de imágenes se han procesado utilizando como herramienta las aplicaciones SNAP (Sentinel Application Platform) y SNAPHU (Statistical-Cost Network-Flow Algorithm for Phase Unwrapping). Una vez obtenidos los mapas de deformaciones se han analizado los movimientos junto con otros datos de la isla como los mapas topográficos, geológicos, geomorfológicos, de pendientes y orientaciones con el propósito de encontrar explicación a cada uno de los movimientos detectados y poder clasificarlos por su tipo de origen.

Se presenta un estudio detallado de las constituyentes de marea en las islas Livingston y Decepción (Antártida), obtenidas en las estaciones mareográficas LIVMAR y DECMAR. Los datos fueron tomados con mareógrafos de sensores de presión. Los cálculos se realizaron a partir de series de marea de largo período, con 798 días de observación, aplicando el método de análisis armónico por mínimos cuadrados. Los resultados obtenidos mejoran trabajos previos en la región, se han obtenido setenta constituyentes, siendo 19 las más representativas con amplitudes superiores a 1 cm y un aporte del 93% de la energía de la onda. En ambas estaciones se confirma que la marea tiene un régimen mixto de comportamiento semi-diurno. Los benchmark de referencia de mareógrafos (TGBM) se encuentran enlazados a las redes geodésicas de control vertical y horizontal de la Antártida, que es de gran importancia para trabajos geodésicos, oceanográficos e hidrográficos en la zona. A detailed study is presented of the tidal constituents for Livingston and Deception Islands (Antarctica) obtained at the LIVMAR and DECMAR tide gauge stations. Data were acquired with tide gauge pressure sensors, and calculated from a long time series of 798 days of data-logging, using the least-squares harmonic estimation method. The results show an improvement over previous results in the region. Seventy tidal constituents were obtained, of which 19 were the most representative with amplitudes greater than 1 cm and a contribution of 93% of the wave energy. In both stations, it was confirmed that the tides are mixed, with a semi-diurnal behavior. The tidal gauge benchmarks (TGBMs) were linked to vertical and horizontal Antarctic Geodetic Networks, which provides a very important contribution for geodetic, oceanographic and hydrographic studies in the area.

En este trabajo se describen y analizan estructuras de segregación en forma de pipe vesicles, normalmente sólo descriptas en la bibliografía para flujos de lava basálticos. En este caso se encuentran en lavas en almohadilla basáltico-andesíticas en la Isla Decepción, Antártida. La génesis de las pipe vesicles en estas lavas basáltico-andesíticas implicó el amalgamiento de muchas pequeñas vesículas de gas que escapaban hacia los bordes de las almohadillas. Estos gases modificaron las condiciones de cristalización en el borde de las vesículas, alterando ligeramente la química y la textura de la roca huésped. Este proceso fue sincrónico o ligeramente anterior a un proceso secundario de oxidación general de la roca huésped causado por los fluidos que fueron retenidos en el interior de las vesículas antes de su escape. La mineralogía y la composición química del borde de las pipe vesicles y roca huésped sugieren que ambas derivan de un único magma. Los procesos físico-químicos durante la cristalización provocaron una concentración de fluidos que modificaron la composición química, la textura y la cristalinidad del magma original, en los bordes de las pipe vesicles. Sugerimos que el proceso de formación de las pipe vesicles podría ser mejor explicado a partir de la circulación e interacción de fluidos, que podrían ser vapor de agua de mar/hielo-nieve y/o fluidos volcánicos., Segregation structures in the form of pipe vesicles, normally described in bibliography only in basaltic lava flows occur in basaltic-andesitic pillow lavas on Deception Island, Antarctica. The genesis of pipe vesicles in these basaltic-andesitic lavas involved the amalgamation of many small gas vesicles that escaped towards the pillows. These gases modified the conditions of crystallisation at the rim of the vesicles, slightly altering the chemistry and texture of the adjacent rock. This process was synchronous with or slightly-earlier than a secondary process of general oxidation of the host rock caused by fluids that were retained inside the vesicles before later escaping. Mineralogy and chemistry of the rim of the pipe vesicles and host rock suggest they both derive from a single magma. Physico-chemical processes during crystallisation caused a concentration of fluids that modified the chemistry, texture and crystallinity of the original magma at the edges of the pipe vesicles. We suggest that the formation of pipe vesicles could be better explained from the movement and interaction of fluids, which may be sea water vapor / ice-snow and / or volcanic fluids., Asociación Argentina de Geofísicos y Geodestas

Se analizó un total de 49 muestras de sedimento marino superficial (< 50 m) extraídas en tres localidades: isla Decepción, bahía Chile y bahía Fildes, península Antártica con el objeto de investigar los foraminíferos del suborden Textulariina, Delage y Herouard, 1886. Se identificaron 22 especies las que fueron clasificadas en 12 familias y 15 géneros. Las especies más abundantes fueron, Trochammina malovensis (53,2%), Miliammina arenácea (16,3%) y Reophax dentaliniformis (6,7%). En isla Decepción se recolectó la mayoría de los ejemplares (57%) y en bahía Chile, el número más alto de especies. La mayor distribución geográfica fue alcanzada por Trochammina malovensis (95,9% de las muestras), Miliammina arenácea (73,5%), Spiroplectammina biformis (63,3%) y Trochammina squamata (61,2%). El análisis de conglomerado y ANOSIM no mostraron diferencias significaticas de las comunidades de las bahías. De las 22 especies identificadas en las aguas antárticas (< 50 m), 10 no han sido citadas en la región austral del continente sudamericano: Alveolophragmiun columbiense, Deuterammina glabra, Eggerella minuta, Pseudobolivina antárctica, Reophax nodulosus, Rhabdammina linnearis, Saccammina sphaerica, Textularia wiesneri, Trochammina malovensis y T. quadriloba, por lo que podrían considerarse endémicas para la región antártica. Forty nine samples, of superficial marine sediments (< 50m.) from 3 localities: Deception Island, Chile Bay and Fildes Bay, Antarctic península were analysed in order to investigate the foraminiferers of suborder Textulariina Delage y Herouard, 1886. Twenty two species were identifed and classiffed en 12 families and 15 generas. The most abundant species were Trochammina malovensis (53,2%), Milia-mmina arenácea (16,3%) y Reophax dentaliniformis (6,7%). Deception Island contributed with most of the specimens (57%) and Chile Bay with the highest number of species. Thes most common species in the area were Trochammina malovensis (95,9% of the samples), Miliammina arenácea (73,5%), Spiro-plectammina biformis (63,3%) and Trochammina squamata (61,2%). Hierarchical cluster analysis and ANOSIM showed there is not communities differences between bays. Ten species (from 22) could not be found in the southernmost southamerica: Alveolophragmiun columbiense, Deuterammina glabra, Eggerella minuta, Pseudobolivina antarctica, Reophax nodulosus, Rhabdammina linnearis, Saccam-mina sphaerica, Textularia wiesneri, Trochammina malovensis and T. quadriloba. Probably they are endemic species for the Antarctic region.

This work deals with the magnetic fabric (AMS technique) of different lithotypes related to quaternary volcanism of Deception Island (South Shetland Islands). The studied rocks include lava flows from basaltic to basaltic-andesitic composition, mafic dykes and several types of pyroclastic deposits. By combining the analysis of parametric aspects of the magnetic ellipsoids and their directional pattern, four types of magnetic fabrics have been recognized. Type I fabrics are related to laminar magma flow in both lava flows and dykes. The second one is related to magma reology in lava flow and tractive streams in pyroclastic deposits. Type III only identified in dikes, characterizes the imbrications of the magma flow against the dyke wall. Type IV reflects an isotropic rock-fabric and has been related to the presence of large anisotropic grains in lavas and particle fall without later modifications in pyroclastic deposits. The obtained results demonstrate the utility of AMS technique for petrogenetic model development linked to rock-fabric acquisition

This work deals with the magnetic fabric (AMS technique) of different lithotypes related to quaternary volcanism of Deception Island (South Shetland Islands). The studied rocks include lava flows from basaltic to basaltic-andesitic composition, mafic dykes and several types of pyroclastic deposits. By combining the analysis of parametric aspects of the magnetic ellipsoids and their directional pattern, four types of magnetic fabrics have been recognized. Type I fabrics are related to laminar magma flow in both lava flows and dykes. The second one is related to magma reology in lava flow and tractive streams in pyroclastic deposits. Type III only identified in dikes, characterizes the imbrications of the magma flow against the dyke wall. Type IV reflects an isotropic rock-fabric and has been related to the presence of large anisotropic grains in lavas and particle fall without later modifications in pyroclastic deposits. The obtained results demonstrate the utility of AMS technique for petrogenetic model development linked to rock-fabric acquisition

Deception Island (South Shetland Islands, Antarctica) is one of the most active volcanoes in Antarctica, having recently erupted in 1967,1969 and 1970. It is also seismically very active, as 1992 seismic crisis was noted. The island has attracted the attention of many geoscientists to study seismo-volcanic events and how they are related with the regional and local tectonic regimes. If so, fractures and faults are involved in most of the geologic and geomorphologic dynamical processes over the island. There is no any unified quality fracture map to study such a surface and subsurface media. Therefore, this work presents a fault traces map interpreted from satellite and aerial photographs, digital elevation model, and bibliographic data. The distribution of trace lengths and orientation takes in account the whole field geological and geophysical observations. The final map has been used to define a tectonic zoning in the Deception Island based on trace scaling properties. Fractal characteristic, as a probabilistic fractal dimension D, has been computed by means of a Levy-Lee flight model. Three different behaviours (D1.5), which mean six different areas over the island, have been detected and associated with the fracture pattern and volcanic processes

Deception Island (South Shetland Islands, Antarctica) is one of the most active volcanoes in Antarctica, having recently erupted in 1967,1969 and 1970. It is also seismically very active, as 1992 seismic crisis was noted. The island has attracted the attention of many geoscientists to study seismo-volcanic events and how they are related with the regional and local tectonic regimes. If so, fractures and faults are involved in most of the geologic and geomorphologic dynamical processes over the island. There is no any unified quality fracture map to study such a surface and subsurface media. Therefore, this work presents a fault traces map interpreted from satellite and aerial photographs, digital elevation model, and bibliographic data. The distribution of trace lengths and orientation takes in account the whole field geological and geophysical observations. The final map has been used to define a tectonic zoning in the Deception Island based on trace scaling properties. Fractal characteristic, as a probabilistic fractal dimension D, has been computed by means of a Levy-Lee flight model. Three different behaviours (D1.5), which mean six different areas over the island, have been detected and associated with the fracture pattern and volcanic processes

La isla Decepción está situada en el Archipiélago de las islas Shetland del Sur y consiste en una caldera volcánica de edad menor que 780000 años, originada a través del colapso tectónico del área central del volcán original. El volcanismo, permanece aún activo, tuvo sus últimas manifestaciones de importancia en las erupciones de los años 1967, 1969 y 1973. En este trabajo, se presenta un estudio geológico integral, a fin de desarrollar un modelo evolutivo de la isla. Se ha recopilado datos geológicos sobre el área tectónica a la cual se halla integrada la isla. En el trabajo de campo, se subdividieron las rocas presentes en tres unidades principales conformadas por tres etapas mayores dentro de una misma evolución: una "precaldera" (Formación Basaltic Shield y diques asociados, Martí y Baraldo, 1990) y una "postcaldera", "Erupciones piroclásticas tempranas", "Erupciones traquíticas" y "Erupciones históricas". Esta división estratigráfica se basa en evidencias de campo y es consistente con los estudios de las propiedades magnéticas de las rocas, entre otras: susceptibilidad magnética total y anisotropía de susceptibilidad magnética. Un estudio paleomagnético integral de las unidades aflorantes permitió establecer que la distribución de los polos geomagnéticos virtuales sigue un ordenamiento consistente con la dividión estratigráfica propuesta. Se determinó la temperatura de emplazamiento de los depósitos piroclásticos de pre y sincaldera de la isla por medio paleomagnéticos, correspondiente a una temperatura que abarca entre los 300 y 400°C para los diferentes tipos litológicos. Se ha recopilado datos geoquímicos de las rocas de la isla y se realizaron once análisis de relaciones isotópicas Sr87/Sr86, en todo el espectro evolutivo (geoquímico y estratigráfico) de la asociación de rocas presentes en la isla; sugiriendo una correspondencia que ubica a dichas muestras en el campo de las rocas de islas oceánicas y que se interpreta como correspondiente a una asociación de rocas de isla oceánica con tendencia tholeítica, producto del ambiente tectónico de arco particular de la zona. Los estudios de direcciones de remanencia magnética realizados indican una polaridad normal para todas las muestras de la isla Decepción, ubicándolas dentro del último período de inversión magnética (de polaridad normal) (límite de Bruhnes-Matuyama; Cand y Kent, 1995). Esto indica una edad menor de 780000 años para todas las unidades de la isla. Las evidencias estructurales de la isla; especialmente la distribución y emplazamiento de las unidades sincaldera sugieren un modelo evolutivo nuevo, que se presenta relacionando el colapso central y lateral del volcán original con la formación de una cuenca de "pull apart" en un ambiente netamente distensivo; donde se conjuga la presencia del "rift" del estrecho de Bransfield y un ambiente trastensivo, producto de la influencia de la falla Hero en el pasaje Drake. Se postula la rotación a partir de un eje vertical del sector noreste de la isla en base a las evidencias de fracturamiento en dicho sector. Palabras Claves: Isla Decepción - Antártida - Volcanismo - Paleomagnetismo - Caldera Volcánica The Deception Island volcanic caldera belongs to the South Shetland Archipelago. It is less than 780.000 years old. The caldera was originated by the tectonic collapse of the central area of the original volcano. The last volcanic eruptions were registered in the years 1967, 1969 and 1970. An integrated geological study with a new evolutive model is presented in this paper. There is a compilation of the tectonic framework of the area with special interest in the basement and the tectonic processes acting in the zone. The stratigraphic units are divided into three main stages: pre-caldera (Yellow Tuff Fm.); pre and syn-caldera (Basaltic Shield Fm. and associated dykes) and post-caldera stages. The last one is divided into different eruptive stages: "early post-caldera eruptions", "early pyroclastic eruptions", "trachytic eruptions" and "historic eruptions". The stratigraphic correlation of the rocks is based on field relations and magnetic properties, as bulk and anisotropy of magnetic susceptibillity. The emplacement temperature of pyroclastic units was inferred, with a 300-400°C average for different lithologic types. A compilation of geochemical data of the rocks is presented with eleven new analysis of isotopic relations of Sr87/Sr86, in the entire suite of rocks (geochemical and stratigraphics). This suggest a relation with tholeitic oceanic islands magmas, interpreted as the result of the emplacement of a volcanic arc in a particular arc in a particular tectonic framework. The magnetic remanence directions indicate a normal polarity for all rocks of the island, corresponding to the last normal chron of magnetic polarity (Bruhnes; Cande y Kent, 1995). This indicates an age of less than 780.000 years for them. Distribution of virtual geomagnetic poles suggest a clockwise loop cosnsistent with the stratigraphic division proposed. The structural study of the island (emphasizes in the emplacement and distribution of the syn-caldera units) leads to a new evolutive model. This model relates the central and lateral collapse of the original volcano with the formation of a pull-apart basin. A small rotation around a vertical axis of some blocks in the noreast area of the island is postulated based on the faulting evidence in this sector. Fil: Baraldo, Andrés. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.

The micro fracture patterns in Deception Island, an active shield volcano located in (he Bransfield Strait, Antarctic Peninsula region, are studied here for the first time. 143 faults have been measured in five sites along the island, three main trends NE-5W, E-W and NW-SE have been established. The average trend of all the measured faults is N46°E. The faults are several meters long and produce small displacement of the pyroclastic layers (up to some tens of centimetres). All of them have a dip higher than 60°, showing in , general a normal sense of movement. This orientation, subparallel to the Bransfield Basin axis, seems to be related to the caldera formation as well as with the subsequent tectonic deformation. These faults are related to a NW-SE extension, compatible with the tectonic setting of this area. The NW-SE faults show directional movement, then they represent, probably, transfer faults of the former group. A small set of normal faults trending E-W has also been measured

The micro fracture patterns in Deception Island, an active shield volcano located in (he Bransfield Strait, Antarctic Peninsula region, are studied here for the first time. 143 faults have been measured in five sites along the island, three main trends NE-5W, E-W and NW-SE have been established. The average trend of all the measured faults is N46°E. The faults are several meters long and produce small displacement of the pyroclastic layers (up to some tens of centimetres). All of them have a dip higher than 60°, showing in , general a normal sense of movement. This orientation, subparallel to the Bransfield Basin axis, seems to be related to the caldera formation as well as with the subsequent tectonic deformation. These faults are related to a NW-SE extension, compatible with the tectonic setting of this area. The NW-SE faults show directional movement, then they represent, probably, transfer faults of the former group. A small set of normal faults trending E-W has also been measured