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5 pages, 5 figures; International audience; We report on a two-dimensional (2D) V1–xPtxSe2 alloy that exhibits ferromagnetic order and Rashba spin–orbit coupling. Although ferromagnetism is absent in 1T-VSe2 because of the competition with the charge density wave phase, we demonstrate theoretically and experimentally that the substitution of vanadium by platinum in VSe2 (10–50%) to form a homogeneous 2D alloy restores ferromagnetic order down to one monolayer of V0.65Pt0.35Se2. Moreover, the presence of platinum atoms gives rise to Rashba spin–orbit coupling in (V,Pt)Se2, providing an original platform to study the interplay between ferromagnetism and spin–orbit coupling in the 2D limit.

La profesion docente constituye un desafio permanente para quienes la ejercemos, debido a que socialmente es una de las profesiones menos valoradas. Sin embargo, en ella recae la obligacion de formar los ciudadanos del futuro, en cualquiera de las epocas en las que se ejerza. Se presenta una aproximacion al deber ser del profesor universitario, teniendo en cuenta que se configura y re-configura en una labor de importancia, asociada a la calidad educativa. Se plantean no solo valores que se deben tener para este ejercicio, sino tambien los retos que el mundo actual en constante cambio le asigna, para la formacion integral de los futuros profesionales. Esta reflexion se realizo a partir de conversaciones academicas de algunos integrantes de la comunidad educativa de un area de la salud. Challenges of the university teacher: a role that is permanently re-configured The teaching profession constitutes a permanent challenge for those who exercise it, because socially it is one of the least valued professions. However, it is the obligation of training the citizens of the future, in any of the periods in which it is exercise. An approach to the duty of the university professor is present, taking into account that it is configure and reconfigure in a work of importance, associated with the educational quality. There are not only values that be taken for this exercise, but also the challenges that the constantly changing world assigns to it for the integral training of future professionals. This reflection was product from academic conversations of some members of the educational community of a health area. Keywords: Professor; university; pedagogics models; didactic; learning. Desafios do professor universitario: um papel que se reconfigura permanentemente A profissao docente constitui um desafio permanente para quem a exerce, pois socialmente e uma das profissoes menos valorizadas. No entanto, sobre ela recai a obrigacao de formar os cidadaos do futuro, em qualquer um dos periodos em que e exercida. Este trabalho apresenta uma abordagem do dever do professor universitario, tendo em vista que ele e configurado e e reconfigurado em um trabalho de importância associado a qualidade educacional. Nao sao apenas os valores que devem ser considerados para este exercicio, mas tambem os desafios que o mundo atual em constante mudanca lhe atribui para o treinamento integral de futuros profissionais. Este estudo/trabalho foi produzido a partir de reunioes de reflexao de alguns membros da comunidade educacional de uma area de saude. Palavras chave: Professor; universidade; modelos pedagogicos; didatica; aprendizagem.

[EN] We present a study of the deformation pattern in El Hierro Island through the analysis of GNSS data from surveys carried out between 2015 and 2019 as well as continuous data. The last eruption in El Hierro occurred under the sea on the south rift, lasted from October 2011 to March 2012, and it was preceded by intense seismic activity and nearly 5 cm ground inflation. After this eruptive cycle, further magmatic intrusions were detected, from June 2012 to March 2014, associated to intense seismic swarms and inflation (about 22 cm of uplift). Nevertheless, these magmatic intrusions did not culminate in any eruption. Following these post-eruptive episodes, the seismic activity became less intense. Thus, for the period of this study, about 500 earthquakes with magnitude ranging from mbLG 2 to mbLG 3.9 were recorded, the ground deformation measured is of lower magnitude, still remaining a slight uplift trend in the GNSS stations up to 2017 and followed by a slight subsidence of about 1.5 cm between 2017-2019. Our purpose is to explain the ground displacements measured and the earthquake occurrence in terms of geodynamics and seismotectonic activity along the island, for the period 2015-2019. Firstly, we retrieved the geodetic velocities from the GNSS daily solutions. Secondly, we computed the 2D infinitesimal strain rates from the velocities through a triangular segmentation approach to map the deformation pattern along the respective GNSS surveys., Projects PID2019-104726GB-I00 and CGL2015- 63799-P of the Spanish Research Agency has supported this research. We wish to acknowledge GRAFCAN (www.grafcan.es) of the Government of the Canary Islands for providing GNSS data from permanent station FRON. Likewise, to the Spanish IGN (www.ign.es) for providing the EH01 and LRES data.

We present a study of the deformation pattern along the Canary archipelago through the analysis of continuous GNSS data. We use data spanning 2011–2017 period to retrieve precise horizontal displacements and a broad calculation of the strain. Geodetic data are interpreted in light of the regional tectonics, which is proven to play a key role in the volcanic eruptions that take place in the archipelago. The common-mode component filtering technique is applied to improve the signal-to-noise ratio of the time series of the GNSS daily solutions before retrieving the geodetic velocities. Through a triangular segmentation approach, we retrieve the 2D infinitesimal strain from the velocities along the Canaries and map deformation patterns in various sectors of the volcanic archipelago. We found areas of maximum deformation west of Tenerife, Gran Canaria and Fuerteventura Islands. A sharp change in shear strain between Tenerife and Gran Canaria is recognized, delineating a sector of intense seismicity, which is mostly associated with a well-known major submarine fault that separates the two insular edifices. On this submarine tectonic structure, we have performed a tentative simulation of the horizontal deformation and strain caused by one of the strongest (mbLg 5.2) earthquakes of the region. Our strain analysis supports the possibility that the main tectonic lineaments are being influenced by the regional stress field. Furthermore, the seismic areas between islands seem mainly influenced by the regional tectonic stress, rather than by the local volcanic activity. This is in accordance with the extensional and compressional tectonic regimes, already identified by other authors, which might favour episodes of volcanism in this volcanic archipelago.

Following the 2004 seismic unrest at Tenerife and the 2011-2012 submarine eruption at El Hierro, the number of GNSS observation sites in the Canary Islands (Spain) has increased, offering scientists a useful tool with which to infer the kinematics and present-day surface deformation of the Canary sector of the Atlantic Ocean. We take advantage of the common mode component filtering technique to improve the signal-to-noise ratio of the velocities retrieved from the daily solutions of 18 permanent GNSS stations distributed in the Canaries. The analysis of GNSS time series spanning the period 2011-2017 enabled us to characterize major regions of deformation along the archipelago through the mapping of the 2D infinitesimal strain field. By applying the triangular segmentation approach to GNSS velocities, we unveil a variable kinematic behaviour within the islands. The retrieved extension pattern shows areas of maximum deformation west of Tenerife, Gran Canaria and Fuerteventura. For the submarine main seismogenic fault between Tenerife and Gran Canaria, we simulated the horizontal deformation and strain due to one of the strongest (mbLg 5.2) earthquakes of the region. The seismic areas between islands, mainly offshore Tenerife and Gran Canaria, seem mainly influenced by the regional tectonic stress, not the local volcanic activity. In addition, the analysis of the maximum shear strain confirms that the regional stress field influences the E-W and NE-SW tectonic lineaments, which in accordance with the extensional and compressional tectonic regimes identified, might favour episodes of volcanism in the Canary Islands., Project CGL2015-63799-P

We report on a detailed geodetic continuous monitoring in Timanfaya volcanic area (TVA), where the most intense geothermal anomalies of Lanzarote Island are located. We analyze about three years of GNSS data collected on a small network of five permanent stations, one of which at TVA, deployed on the island, and nearly 20 years of tiltmeter and strainmeter records acquired at Los Camelleros site settled in the facilities of the Geodynamics Laboratory of Lanzarote within TVA. This study is intended to contribute to understanding the active tectonics on Lanzarote Island and its origin, mainly in TVA. After characterizing and filtering out the seasonal periodicities related to “non-tectonic” sources from the geodetic records, a tentative ground deformation field is reconstructed through the analysis of both tilt, strain records and the time evolution of the baselines ranging the GNSS stations. The joint interpretation of the collected geodetic data show that the area of the strongest geothermal anomaly in TVA is currently undergoing a SE trending relative displacement at a rate of about 3 mm/year. This area even experiences a significant subsidence with a maximum rate of about 6 mm/year. Moreover, we examine the possible relation between the observed deformations and atmospheric effects by modelling the response functions of temperature and rain recorded in the laboratory. Finally, from the retrieval of the deformation patterns and the joint analysis of geodetic and environmental observations, we propose a qualitative model of the interplaying role between the hydrological systems and the geothermal anomalies. Namely, we explain the detected time correlation between rainfall and ground deformation because of the enhancement of the thermal transfer from the underground heat source driven by the infiltration of meteoric water., Projects CGL2015-63799-P of Spanish Ministry of Economy and Competitiveness, and 320/2011 of National Parks Autonomous Agency have supported this research.

Timanfaya National Park is a volcanic area located in the southwest of Lanzarote Island (Canary Islands, Spain). Several lava tubes have been found in the lava flows but many others remain unknown. Its location and identification are important to mitigate collapse hazards in this touristic area. We present a new study about the location of recent lava tubes by the analysis and joint interpretation of around penetrating radar (GPR), microgravity and electromagnetic induction (EMI) data along the same profile over an area not previously surveyed. GPR data display a complex pattern of reflections up to ~10 m depth. The strongest hyperbolic reflections can be grouped in four different areas. Visual inspections carried out in the field allow confirming the occurrence of lava tubes at two of them. These reflections have been interpreted as the effect of the roof and bottom interfaces of several lava tubes. The microgravity survey defines a wide gravity low with several over-imposed minor highs and lows. Using the GPR data, a 2.5D gravity model has been obtained revealing four lava tubes. EMI data have been used to obtain an inverted resistivity model that displays four high resistivity areas that closely match the locations of the lava tubes derived from the previous methods. This resistivity model exhibits the lower resolution although reaches a deeper investigation depth (~20 m). The comparison of the results has revealed that joint interpretation of GPR, microgravity and EMI methods provides reliable models useful for the detection of unknown shallow lava tubes

Pico Island is the youngest (< 300 ka) island of the Azores archipelago, dominated on its western sector by the stratovolcano of Pico Mountain, which rises about 3.5 km above the surrounding ocean floor. The other two major morpho-tectonic units of the island include the shield volcano of Topo, and the "Achada Plateau," a 29 km long volcanic ridge, with a WNW-ESE trend. A gravimetric study on Pico Island, coupled with geological and volcanological data, was aimed towards a better understanding of its deep volcano-tectonic structures. From a total of 407 stations, a regional model of density contrasts was developed in order to reproduce the crustal structure of the island. In addition a local high-resolution model of the sub-surface structure of the westernmost part of the island is presented. Both models were obtained by means of an inversion global adjustment, on fixed density contrasts in order to determine the three-dimensional geometry of the sources of the anomalous gravity field. The most prominent anomalous gravity structure found in Pico Island is a body with positive density contrast located on the SE slopes of Topo volcano. This anomaly extends to depth of approximately 8 km (mean depth of 4.5 km) and has a volume of 310 km(3). This anomaly maybe best interpreted by the presence of a major intrusive system beneath Topo volcano and can be also correlated to gravitational collapses at the shield volcano. A second body of positive density contrast which appears to extend to 4-5 km depth is located near the town of Madalena. This anomaly may be correlated to a high-density anomaly recently detected in the NE sector of Faial Island. Smaller sized high-density bodies at shallow depths of around 1.3 km are located beneath Pico Mountain volcano and all together define a semi-circular arc with an average diameter of 8 km. We propose that this arcuate structure might outline a ring fracture associated with the collapse of the central sector of Pico Mountain volcano early in its growth. Low-density bodies are located on the NW flanks of Pico Mountain, along a linear ENE trending structure. These bodies extend to depths of 4 km and have a total volume of 69 km(3). They are interpreted as being associated with an "old" extensional fracture zone. Previous studies suggested the existence of a shallow and large magma reservoir (with volumes up to 1000 km(3)) beneath Pico Mountain volcano. In this study we have not found any evidence of the existence of such huge magma body. On the contrary, we propose that those discrete low-density bodies correspond to complex intersections of different sets of tectonic lineaments, along which magma tends to intrude, as shallow (2-5 km) and small (10-20 km(3)) magma pockets. (c) 2006 Elsevier B.V. All rights reserved.

A 12-year series (1992–2004) of strain measurements recorded in the Geodynamics Laboratory of Lanzarote is investigated. Through a tidal analysis the non-tidal component of the data is separated in order to use it for studying signals, useful for monitoring of the volcanic activity on the island. This component contains various perturbations of meteorological and oceanic origin, which should be eliminated in order to make the useful signals discernible. The paper is devoted to the estimation and elimination of the effect of the air temperature inside the station, which strongly dominates the strainmeter data. For solving this task, a regression model is applied, which includes a linear relation with the temperature and time-dependant polynomials. The regression includes nonlinearly a set of parameters, which are estimated by a properly applied Bayesian approach. The results obtained are: the regression coefficient of the strain data on temperature is equal to (−367.4 ± 0.8) × 10 −9 °C −1 , the curve of the non-tidal component reduced by the effect of the temperature and a polynomial approximation of the reduced curve. The technique used here can be helpful to investigators in the domain of the earthquake and volcano monitoring. However, the fundamental and extremely difficult problem of what kind of signals in the reduced curves might be useful in this field is not considered here.

From the data of a microseismic survey of the Lanzarote Island territory (Canary Archipelago) we obtained a microseisms amplitude distribution in the frequency range 0.3–12.5 Hz. We found a distinguished anomaly such as an amplitude depression, whose size and magnitude depend on the frequency. After studying the statistical and polarization properties of microseism signals we proposed a model explaining this depression, based on the presence of a rigid intrusive body in the center of the island. Results of our survey coincided well with independent detailed gravity survey results whose interpretation also implies the presence of intrusion. We estimated shear-wave velocity for the rocks of intrusion and for surrounding rocks using microseismic data.

—A ground penetrating radar survey is presented over a recent lava flow at the volcanic area of Timanfaya National Park (Canary Island, Spain). The purpose was to locate lava tubes into the lava flow through the combination of field and simulated data. Different modelling strategies were used for the analysis and knowledge of the signal behaviour. Finite-difference time-domain algorithm was considered for simulations, and the pattern of reflections generated from previously known volcanic structures were characterized. After the characterization of the radar-wave response, the interpretation achieved was applied over the field data acquired at other non-studied area in which different lava tubes were recognized., Authors thanks to the financial support of the National Parks Network of the Spanish Ministry of Environment and Rural and Marine Affairs (320/2011 – project “Caracterización estructural del Parque Nacional de Timanfaya mediante uso combinado de técnicas y métodos geodésicos y geofísicos”. The staff of National Park of Timanfaya is also acknowledged, as well as the Applied Geotechnologies research group from the University of Vigo for providing the RAMAC/GPR equipment. Additionally, this study is a contribution to the EU funded COST Action TU-1208.