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The area of the Betic Cordillera, located in Southern Spain, is an active earthquake region. On May 11 2011, a 5.1 magnitude earthquake occurred with epicenter near the town of Lorca. This seismic event was generated on the Al-hama de Murcia fault. In this paper we present the results of processing the GPS data corresponding to the time at which the event occurs, using the PPP processing strategy. We detected the event in one of the stations of the Meristemum network used in the study, despite being a low magnitude event. From the results we were able to obtain a direct value of the displacement generated by the strong ground motion, as well as an approximate value of the acceleration at the site. For a better detection of the precise instant in which the station records the arrival of the surface wave, a Wavelet filtering is applied on the obtained time series.

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 island9s 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 Island9s most relevant tectonic, geomorphological, volcanological and magmatic features, as well as the results obtained from decades of monitoring the island9s seismic activity and ground deformation.

On 10 October 2011, a submarine eruption occurred in El Hierro island. Thus, the eruptive process in the Canary islands was reactivated after 40 years of inactivity. The main objective of this work is to evaluate, using Functional Data Analysis, how the surface deformation phenomenon explains the seismic–volcanic activity in the island. The GNSS-GPS data are from the FRON (GRAFCAN) station, located in Frontera. These data measure, each 4 h, the distance between the FRON station and the reference station LPAL (La Palma island) from August, 2010 to December, 2013. In this study a functional correlation measure is employed to establish the relation between the deformation curve and the curve of cumulative energy released. The period of time analysed has been divided into four phases to avoid the mix of phenomena. For each phase, the correlation measure and the time lag between deformation curve and the curve of cumulative energy released have been estimated. These values show a strong relation between these curves. With respect to time lag period, the only significant lag, of about 1 month, occurred in Phase 1, which was after a long period without seismic activity. The later phases had very short, insignificant, lags. After a long period without seismic and volcanic activity in El Hierro island, the time lag between the deformation process and the beginning of the seismic activity takes approximately 1 month. In a similar situation a method to predict in real time the beginning of the seismic activity is proposed. This method, based on the changes produced in the derivative curves when there is a rapid descent in the deformation curve, could activate a warning system approximately 13 days before the beginning of seismicity.

At present, different methods are used for processing GPS time series data obtained from a network of GNSS stations. Solutions converted to velocity and displacement allow the generation of different geodynamic models in areas influenced by tectonic and volcanic activity. This study focuses on the comparative analysis of the solutions obtained through different processing techniques: Precise Point Positioning (PPP) and Relative Positioning using specialized scientific software (Bernese 5.2). Another important objective of this study is the analysis of the convergence of linear and non-linear time series to determine the accuracy in each component (east, north, up), in addition to the application of statistical techniques and data filtering (1-sigma, 2-sigma, kalman, wavelets, and CATS analysis) to check the behavior of the series. These processing and analysis techniques will be applied to different series obtained from the main stations used for tectonic and volcanic monitoring in the Central America region (Guatemala, El Salvador, Honduras, Nicaragua, and Costa Rica) in order to establish a regional geodynamic model.

GNSS systems allow precise resolution of the geodetic positioning problem through advanced techniques of GNSS observation processing (PPP or relative positioning). Current instrumentation and communications capabilities allow obtaining geocentric and topocentric geodetic high frequencies time series, whose analysis provides knowledge of the tectonic or volcanic geodynamic activity of a region. In this work, the GNSS time series study was carried out through the use and adaptation of R packets to determine their behavior, obtaining displacement velocities, noise levels, precursors in the time series, anomalous episodes, and their temporal forecast. Statistical and analytical methods were studied, for example, ARMA, ARIMA models, least-squares methods, wavelet functions, and Kalman techniques. To carry out a comparative analysis of these techniques and methods, significant GNSS time series obtained in geodynamically active regions (tectonic and/or volcanic) were considered.

Este trabajo presenta un estudio detallado para la determinación del nivel medio del mar (NMM), las constituyentes de marea y un geoide de precisión en las islas Decepción y Livingston y el entorno del mar de Bransfield. Para realizar estos trabajos es necesario definir el marco de referencia geodésico, para ello se han utilizaron las redes geodésicas REGID (Red Geodésica de Isla Decepción), RENID (Red de Nivelación de Isla Decepción) y REGRID (Red Gravimétrica de Isla Decepción), utilizando como vértices fundamentales algunos puntos pertenecientes a la red RGAE (Red Geodésica Antártica Española). Los datos de marea fueron obtenidos mediante sensores de presión instalados en las estaciones mareográficas de LIVMAR y DECMAR, islas Livingston y Decepción respectivamente. Se obtuvieron las primeras series temporales con 798 días de observación en ambas estaciones, cuyo análisis armónico nos proporcionó 70 constituyentes de marea, siendo 19 las más representativas con amplitudes superiores a 1 cm. Se determinamos el nivel medio del mar, utilizando como puntos fundamentales el LN00 (I. Decepción) y BEJC (I. Livingston). Por último, se determinó el modelo de geoide de precisión, GeoiDEC14, calculado a partir de mediciones GPS, gravimétricas y de nivelación y cuyo resultado ha sido contrastado con los modelos globales más actuales. Estos son los primeros resultados de determinación del nivel medio del mar y la obtención de un modelo de geoide de precisión en esta zona de la Antártida y mejoran trabajos previos realizados en la región.

Macaronesia is a complex oceanic region spanning three tectonic plates in the northeast Atlantic ocean. It is composed of four archipelagos, widely distributed and limited to the east by the Iberian Peninsula and north-western coast of Africa. This study aims to clarify recent Macaronesian kinematics from 19 GNSS stations located on the four archipelagos and the Iberian and African coastlines. The analysis is based on nearly 15 years of common data acquisition and aimed to detect new effects of intraplate tectonics or similar local/regional events consistent with calculated ground displacements. Evaluating the GNSS stations residual velocities relative to those expected from the NNR-MORVEL56 model, higher residuals were found at continental coastal stations (Africa) than at oceanic ones (Canaries and Madeira). From the computed strain rate map, the possible existence of a shear zone connecting the Gloria and Transmoroccan fault systems, already mentioned by other authors, was depicted. Cluster statistical analysis of the horizontal residual velocities helped to identify tectonic boundaries in Macaronesia and four groups of analogous intraplate residual velocities within this region. Three of four groups were identified in the Azores, highlighting the African-Nubian-Eurasian diffuse plate boundary in this region. Furthermore, in the Canary Islands, two distinct kinematic behaviours were detected, possibly due to the activity along a previously detected tectonic fault between Tenerife and Gran Canaria, where some stations have similar intraplate residuals to those at Madeira and Cape Verde stations, while others have similar intraplate residuals to those of continental stations. Finally, all stations on oceanic crust, except Cape Verde, present recent ground subsidence which may be attributed to isostatic adjustment. info:eu-repo/semantics/publishedVersion

Nowadays, both, the number of observations and the accuracy of satellite-based geodesic measurements, like GNSS, have increased. Therefore, GNSS provides more data as displacement values and velocities. This paper demonstrates that GNSS data analysis is a powerful tool to study geodynamic processes.In this study, the analyzed GNSS data correspond to continuously recorded GPS (CGPS) stations, what we call the SPINA network. These stations are located in a region called Ibero-Maghrebian which includes the southern areas of the Iberian Peninsula and northern Africa.The CGPS stations are included in the following organizations: RENEP (National Network of Permanent Stations), RAP (Andalusian Positioning Network), the Murcia Region CGPS Networks, ERVA (Valencian Reference Stations Network), IGN (National Geographic Institute) and the network TOPOIBERIA. The velocity was obtained in two steps: (1) preprocessing position time-series data of daily GPS measurements and (2) applying a combined model using the weighted least-squares method.The prior knowledge of the crustal strain rate tensor provides a description of geodynamic processes such as the fault strain accumulation.Based on the distribution of the GNSS stations, several grid sizes were tested to identify the best resolution. A Python script was used to compute the full two-dimensional velocity gradient tensor by means of inverting the GNSS velocities. The tensorial analysis provides different aspects of deformation, such as the maximum shear strain rate, including its direction, and the dilatation strain rate. These parameters can be used to characterize the mechanism of the current deformation.Based on the computations from the GNSS-data model of components of horizontal deformations, the rates of both principal, values and axes, of the Earth’s crust deformation were found. Deformations measured in the Ibero-Maghrebian region with GPS could be interpreted in terms of either elastic loading or ductile deformation.

Gulf of Cadiz from the Strait of Gibraltar to the Western Coast of the Iberian Peninsula is a natural hazard risky region due to the existence of several active faults related to the Eurasian and Nubian Plate interaction. The 1755 Lisbon Earthquake was remarkable example. With the epicenter located SW of Cape San Viente, and a Richter scale magnitude around 8.3, the earthquake triggered a devastating tsunami hitting the Portuguese, Moroccan and Southern Spain coasts, resulting in thousands of casualties. More recently, in 1969 a 7.8 magnitude earthquake with its epicenter located in the same region, originated another tsunami but smaller than the previous one, resulting nineteen casualties.To prevent natural hazards like these, the Astronomy, Geodesy and Cartography Laboratory at the Universidad de Cadiz, is drawing and implementing early warning systems, trying to detect and evaluate tectonic activity in near real time at the Gulf of Cadiz. The system includes the GNSS network SPINA receivers together with MEMS acelerometers, meteo equipments, and ancillary instrumentation for data adquistion, monitoring, quality control and results display at a dedicated control center.

This paper demonstrates the usefulness of approaching the dynamic study of the precise positioning of a network of permanent global positioning system (GPS) stations through functional data analysis. The displacement data for each GPS station, obtained from observations of the global navigation satellite system, are a discrete sample of the positioning curve. The aim of this paper is to reconstruct the original functions in order to use them as functional data. In the method presented in this paper, the geodetic series are obtained first by processing the GPS data with respect to a reference station. Second, for each station, a cleaning process is applied to eliminate the values considered as outliers, and the missing values are imputed by using a Kalman filter. Finally, the original functions are reconstructed by using smoothing techniques and by evaluating several bases of functions. Moreover, these functions are treated with statistical techniques for functional data. This procedure is applied to the permanent stations of the south of the Iberian peninsula and the north of Africa (SPINA) network. The topocentric series: east, north and up are analysed. In the analysis of the positioning curves, there is observed a synchronized behaviour of the functions in those periods of time with important seismic activity. This behaviour also appears in the analysis of the second principal component of the East and up dimensions. Furthermore, the first two principal components of the East coordinate enable us to make a classification of the stations in the SPINA network. The classification made is consistent with the previous knowledge of the tectonic plates in the studied area.

Traditionally volcanic-hazard assessments have been applied to stratovolcanoes, where volcanic hazard maps represent important tools for volcanic crisis management and land-use planning. In recent years, several improvements have been made for monogenetic volcanic fields focused on, among other things, the development of spatial models to deal with one of the main problems in these areas, namely the unknown vent location. However, volcanic hazard maps of monogenetic volcanic fields present some significant differences with respect to those developed for stratovolcanoes, including the fact that they commonly represent multiple eruptive processes spread over the possible vent opening area. Likewise, the scientific communication of the volcanic-hazard assessment and how this information is comprehended are critical issues in the development of mitigation strategies for monogenetic volcanic fields. In this research, we focused on developing volcanic hazard maps using simple numerical hazard models in combination with a random approach for vent location to cover the whole vent opening area. We added some spatial methods to better manage potentially affected areas. The maps were designed for use in a digital environment (Geographic Information System) by Civil Protection professionals in high-risk monogenetic volcanic fields on small oceanic islands. The methodology presented does not use susceptibility base maps for hazard assessment to avoid possible underestimation of low probability areas by Civil Protection. The methodology represents an attempt to respond to the most important questions of where, when and how a new eruption might take place in a monogenetic volcanic field. The example presented here was developed for La Palma (Canary Islands).

Deception Island (South Shetland Islands) is one of the most active volcanoes in Antarctica. In the 1988–1989 austral summer, after the most recent eruptive process on the island (1967–1970), monitoring of volcanic activity through geophysical and geodetic techniques was resumed by Spanish and Argentinean scientists. In order to monitor the island's tectonic and volcanic behavior, a geodetic network was deployed. Currently, this network consists of 15 geodetic benchmarks located around Port Foster, Deception's inner bay open to the sea. Two additional geodetic benchmarks were installed outside Deception Island to be used as reference benchmarks for the differential positioning strategy. Since 1991–1992, geodetic ground-displacement velocities between the successive austral summer Antarctic campaigns have been computed and analyzed. The overall geodynamic behavior of Deception Island within the South Shetland Islands, Antarctic Peninsula and Bransfield Basin regional environment has been analyzed from geodetic ground-displacements. Results obtained demonstrate that Deception and Livingston island have a similar behavior derived from the Bransfield Basin extension and the Phoenix micro-plate subsidence processes. However, Deception Island is also highly influenced by its volcanic activity. Deception Island's volcanic behavior between 1991 and 2018 is shown by the velocity field, strain tensors and pressure source evolution obtained from the ground-displacements at the geodetic benchmarks. During this time period, it is possible to identify different inflation and deflation phases separated by transitional (or mixed) stages of extension without uplift and compression without subsidence. The most representative inflation and deflation periods were analyzed in detail, to show how they correlate with high and low seismic activity, respectively. The transitional or mixed stages, seem to be the precursors of the next inflation or deflation phase being the Bransfield basin rifting and NW-SE extension the potential related process. Finally, we have analyzed the processes that occurred prior to the volcanic unrests of 1999–2000 and 2012–2013. In both cases, an increase in detected seismic activity and/or soil and seawater temperature was observed and a mixed phase of extension without uplift seems to be precursory to the volcanic unrest. The correlation between the inflation processes, identified by ground-displacement of the network geodetic benchmarks, the increase in seismicity and the increment of soil and seawater temperature makes these transitional mixed phases potential precursors of Deception Island's volcanic unrest periods. © 2019 Elsevier B.V.

After the 2004 unrest on Tenerife (Canary Islands), the Global Navigation Satellite System (GNSS) network called TEGETEIDE was designed and deployed with seven survey mode stations to contribute to a volcanic alert system. Starting in 2008, public access data from continuous GNSS stations, managed by public institutions, were included in this network allowing measurement of ground displacement at 14 locations in Tenerife. Data acquired from 2005 to 2015 was analysed to assess ground deformation in Tenerife following the 2004 volcanic unrest. The overall ground deformation depicted compression in the central Las Cañadas Caldera possibly caused by gravitational subsidence of the high central volcanic cone. This sinking is generalised around the whole island but is less in the northeast (Anaga Massif) where we found an extension rate close to 200 strain/y that could be related to a secondary submarine fault accommodating rifting to the northeast and isolating the behaviour of this massif. At the south volcanic field (south rift), another localized area with an extensional deformation was detected, possibly resulting from the subsurface fluid migration or mass addition that caused the 2004 volcanic unrest because is located following the seismic swarm alignment along Icod Valley towards Roque del Conde massif that persists since that event. We also detected residual plate velocity indicating movement of Tenerife towards Gran Canaria that should be studied in the context of the entire Canary Islands archipelago., This research has been partially funded by the projects TEGETEIDE (CGL2004-21643E), METOTEIDE (CGL2005-25066E), VOLRESTE (CGL2009-MEC) and PEVERTE (CGL2011-28682-C02-01) as well as the 200430E438 CSIC project.

Deception Island is an active volcano located in Bransfield Strait. Its volcanic activity is linked to the presence of gravity anomalies that influence the definition of the geoid. In this paper, a precise undulation geoid model (GeoiDEC14) has been computed from GPS, gravimetric and levelling measurements. GeoiDEC14 highlights local anomalies of the island that match with hot spots, such as the minimum values shown in Fumarole Bay and Whalers Bay (fumarole areas), or the maximum values found in the remains of lava at Colatinas, Black Glacier and Murature Point. Comparison of GeoiDEC14 with global models always shows negative values due to an average of 18.80 m for our model compared to 19.80–20.60 m for models such as ITSG-Grace2014s, EGM08, AIUG-Grace03s or EGM96. This difference is due to the lack of resolution of global models and to the volcanic activity on the island. To confirm the results, the same measurements were taken on nearby Livingston Island. The values of geoid undulation on this island reaffirm the lack of detail in the global geoid in the area, presenting an average of 18.90 m, similar to the average value of GeoiDEC14.

La base de datos de la Red Hidrometrica de la Armada Boliviana (RHAB) carecia de la agilidad de consulta, por lo que precisa de un moderno gestor de informacion espacial y de base de datos para la optimizacion del manejo de los recursos hidrologicos. Por ello, se presenta una nueva metodologia, generalizable a cualquier pais, para desarrollar un sistema multidisciplinario de informacion geografico (SIG) en Internet. Es de facil e intuitiva utilizacion, orientado a la gestion de informacion hidrometrica para alerta temprana, apoyo a la navegacion, al transporte fluvial y lacustre, para proyectos y obras de investigacion, ingenieria, cartografia, pesca y turismo, entre otros. El acceso a la base de datos geografica que contiene la informacion hidrologica se realiza mediante Internet, con un visor web geografico. Se han integrado diferentes aplicaciones de software de distribucion libre, junto con diversos lenguajes de programacion. La disposicion inmediata de datos precisos coadyuva en la prevencion de desastres por inundaciones.

Increased thermal activity was detected to coincide with the onset of volcano inflation in the seawater-filled caldera at Deception Island. This thermal activity was manifested in pulses of high water temperature that coincided with ocean tide cycles. The seawater temperature anomalies were detected by a thermometric sensor attached to the tide gauge (bottom pressure sensor). This was installed where the seawater circulation and the locations of known thermal anomalies, fumaroles and thermal springs, together favor the detection of water warmed within the caldera. Detection of the increased thermal activity was also possible because sea ice, which covers the entire caldera during the austral winter months, insulates the water and thus reduces temperature exchange between seawater and atmosphere. In these conditions, the water temperature data has been shown to provide significant information about Deception volcano activity. The detected seawater temperature increase, also observed in soil temperature readings, suggests rapid and near-simultaneous increase in geothermal activity with onset of caldera inflation and an increased number of seismic events observed in the following austral summer.

Subduction comes to an end when all oceanic lithosphere is consumed and continental or transitional crust, with positive buoyancy, becomes involved. During continental collision, the final stage of subduction may be characterized by slab breakoff, limited continental subduction, and delamination below the fold-and-thrust belt. We report receiver function images, constructed from a dense array of seismic broadband stations, that reveal the underthrusting of Iberia beneath the Alboran plate. The underthrusted crust is delaminating beneath part of the Betic mountain range, still connected to the foreland lithosphere on one side, and interrupted discontinuously along the other side. Intermediate deep earthquakes associated with the delamination process do not respond to downdip stresses like subduction earthquakes. The GPS velocity field and source mechanisms for shallow earthquakes demonstrate ongoing active shortening on top of the hinge of delamination, and localized perpendicular extension on top of the edge of delamination, introducing independent motion of the overriding crustal block. Delamination beneath the Betic Range drives seismicity by inducing fundamental changes in deformation patterns within the collision orogen.

This article describes a reconstruction made of the palaeo-volcanic edifice on Deception Island (South Shetland Islands, Antarctica) prior to the formation of its present caldera. Deception Island is an active Quaternary volcano located in the Bransfield Strait, between the South Shetland Islands and the Antarctic Peninsula. The morphology of the island has been influenced mainly by the volcanic activity but geodynamics and volcanic deformation have also contributed. A volcanic reconstruction method, the Geodynamic Regression Model (GRM), which includes a terrain deformation factor, is proposed. In the case of Deception Island, the directions of this deformation are NW–SE and NE–SW, and match both the observed deformation of the Bransfield Strait and the volcanic deformation monitored over the last 20 years in the island, using Global Navigation Satellite System (GNSS) techniques. Based on these data, possible volcanic deformation values of 5–15 mm/yr in these directions have been derived. A possible coastline derived from a current bathymetry is transformed, according to values for the chosen date, to obtain the palaeo-coastline of Deception Island of 100 k years ago. Topographic, geomorphologic, volcanological and geological data in a GIS system have been considered, for computation of the outside caldera slope, palaeo-coastline, palaeo-summit height and palaeo digital elevation model (DEM). The result is a 3D palaeo-geomorphological surface model of a volcano, reaching 640 m in height, with an increase of 4 km3 in volume compared to the current edifice, covering 4 km2 more surface area and the method reveals the previous existence of parasite volcanoes. Two photorealistic images of the island are obtained by superposition of textures extracted from a current Quick Bird satellite image also. This technique for reconstructing the terrain of an existing volcano could be useful for analysing the past and future geomorphology of this island and similar locations.

As it is well known, GNSS data analysis is a powerful tool to study geodynamic processes. However, observational methodologies and data analysis results should be adapted to determine local or even regional effects. It is particularly important in tectonic plate boundary areas when looking for subduction zone limits.

The South Shetland Islands archipelago is dynamically complex due to its tectonic surroundings. Most islands are part of a formerly active volcanic arc, although Deception, Penguin and Bridgeman Islands, as well as several submarine volcanoes, are characterized by active back-arc volcanism. Geodetic benchmarks were deployed and the movement of the lithosphere to which they were fixed measured to provide geodynamic insight for the South Shetland Islands, Bransfield Basin and Antarctic Peninsula area based on surface deformation. These benchmarks' data add spatial and temporal coverage to previous results. The results reveal two different geodynamic patterns, each confined to a distinct part of the South Shetland Islands archipelago. The inferred absolute horizontal velocity vectors for the benchmarks in the northeastern part of the archipelago are consistent with the opening of the Bransfield Basin, while benchmark vectors in the southwestern part of the archipelago are similar to those of the benchmarks on the Antarctic Peninsula. In between, Snow, Deception and Livingston Islands represent a transition zone. In this area, the horizontal velocity vectors relative to the Antarctic plate shift northeastwards from N to NW. Furthermore, the South Shetland Islands benchmarks, except for that at Gibbs (Elephant) Islands, indicate subsidence, which might be a consequence of the slab roll-back at the South Shetland Trench. In contrast, the uplift revealed by the Antarctic Peninsula benchmarks suggests glacial isostatic adjustment after the Larson B ice-shelf breakup., This geodetic research has been carried out with the support of the Spanish Ministry of Education and Science as part of the National Antarctic Program. The following research projects contributed directly to this work: “Recognition and fast evaluation of volcanic activity on Deception Island (GEODESY) (ANT1999-1430-E/HESP)”; “Geodetic Studies on Deception Island: deformation models, geoid determination and Scientific Information System (REN2000-0551-C03-01/ANT)”; “Acquisition of scientific software for GPS data processing (REN2000-2690-E)”; “Geodetic Control of the volcanic activity of Deception Island (CGL2004-21547-E/ANT)”; “Update of the Spanish Cartography for Deception Island (CGL2004-20408-E/ANT)”; “Volcano-tectonic activity on Deception Island: geodetic, geophysical investigations and Remote Sensing on Deception Island and its surroundings (CGLl2005-07589-c03-01/ANT)”; and “Geodetic and Geothermal Researches, Time Serial Analysis and Volcanic Innovation in Antarctica (South Shetland Islands and Antarctic Peninsula (GEOTINANT) (CTM2009-07251/ANT))”.

The Andalusian Positioning Network (RAP) is a regional GNSS permanent network in southern Spain that offers two public services for precise positioning: real-time (RAP-IP) and post processing (RAP-FTP). The most of registered users are linked to the construction sector, so the collapse of the housing bubble and the Spanish economic crisis influenced the use of RAP services from 2008. The behavior of these services has differed somewhat, although analysis for the years 2008 to 2013 reveals a general decline. Since 2009 the RAP-FTP service demand fell by 50%, but the RAP-IP service was stable until October 2011, when it began a steep decline in December 2012. Analyzing the temporal demand and the geospatial connections of RAP-IP with economic impact indicators, we found a high linear correlation between this service and jobs in the construction sector (0.98) and permit building (0.96). The real time and associated geoinformation are its main advantages.

Surface deformation parameters and its use in volcano monitoring have evolved from classical geodetic procedures up to those based on Global Navigation Satellite Systems (GNSS), in particular the most widely used and known Global Positioning System (GPS), profiting from the automated data processing, positioning precision and rates, as well as the large storage capacity and low power consumption of its equipments. These features have enabled the permanent GNSSGPS data acquisition to ensure the continuous monitoring of geodetic benchmarks for the evaluation of surface deformation in active tectonic or volcanic areas. In Deception Island (Antarctica), a normal vector analysis is being used to give surface deformation based on three permanently observed GNSSGPS benchmarks. Due to data availability, both in the past and for near real-time use, all benchmarks used are inside the monitored volcanic area, although the reference is away from thermal springs and/or fumaroles, unlike the other two. The time variation of slope distances to the reference benchmark and of the magnitude and inclination of the normal vector to the triangle defined by the reference benchmark and any other two, provides the spatial deformation in the volcanic area covered. The normal vector variation in magnitude gives information on compression or expansion, here called spatial dilatometer, while the changes in inclination gives information on relative uplift or subsidence, here called spatial inclinometer. In geodesy, the triangle is a basic geometric unit and the areal strain is commonly applied in tectonics and volcanism. The normal vector analysis conjugates both, benefiting from the method's precision, simplicity and possibility to model the surface using several triangles. The proposed method was applied to GNSSGPS data collected every austral summer between 20012002 and 20092010 in Deception Island. The results evidence that Deception Island acts as a strain marker in the Bransfield Basin volcano-tectonic setting. Spanish Ministry of Education and Science as part of the National Antarctic Program; Recognition and fast evaluation of volcanic activity on Deception Island (GEODESY) [ANT1999-1430-E/HESP]; Geodetic Studies on Deception Island: deformation models, geoid determination and Scientific Information System [REN2000-0551-C03-01/ANT]; Acquisition of scientific software for GPS data processing [REN2000-2690-E]; Geodetic Control of the volcanic activity of Deception Island [CGL2004-21547-E/ANT]; Update of the Spanish Cartography for Deception Island [CGL2004-20408-E/ANT]; Volcanotectonic activity on Deception Island: geodetic, geophysical investigations and Remote Sensing on Deception Island and its surroundings [CGLl2005-07589-c03-01/ANT]; Geodetic and Geothermal Researches, Time Serial Analysis and Volcanic Innovation in Antarctica (South Shetland Islands and Antarctic Peninsula (GEOTINANT) [CTM2009-07251/ANT] info:eu-repo/semantics/publishedVersion

During the nearly 40 years covered by the study, major height differences of over ± 25 m have been revealed in the volcanic landscape of the 1970 craters in Deception Island, an active volcano in the South Shetland Islands (West Antarctica). In the last 14 years, the mean volcanic filling rate has been 1 m yr-1 and the mean erosion rate has been -0.2 m yr-1. There has been considerable landform modification mainly associated with landslide-induced accumulation, and erosion may indicate the craters’ fill over the next 30–40 years. Deception Island's eruptions have been recorded since 1842. Special attention was paid to the zones affected by the most recent volcanic events and the geomorphological changes that have taken place in those zones since then (e.g. the 1970 volcanic craters area in the last episode occurring between 1967 and 1970). Historical maps (produced before and just after the 1970 eruption) were compared with maps plotted in 1992 and updated using a 2003 image from the Quickbird satellite and data obtained with Global Navigation Satellite System technology in 2006. Techniques used included both geodetic transformation and the geometric correcting of maps.

Deception Island is an active volcano in the South Shetland Islands (Antarctic). Its eruptions have been recorded since 1842, the last episode occurring between 1967 and 1970. This study quantifies the geomorphological changes which have taken place as a result of historical volcanic activity on the island. The linear and volumetric results obtained for the Telefon Bay and Craters of 1970s where the Surtseyan eruption took place in 1967 are presented in detail, Departamento de Ingeniería Gráfica, Universidad de Sevilla, España, Laboratorio de Astronomía, Geodesia y Cartografía, Universidad de Cádiz, España, Departamento de Investigación y Prospectiva Geocientífica, Instituto Geológico y Minero de España, España

During the 2007–08 Spanish Antarctic campaign, two moorings of bottom pressure sensors were carried out over a ten week period. This paper presents the results of the tidal analysis from sea level records obtained at Deception and Livingston islands (South Shetland Islands, Antarctica). The main objective of this paper is to present a detailed study of the tidal characteristics at these two islands, for which statistical and harmonic analysis techniques are applied to the tidal records. A geodetic network was used to reference the pressure sensors. Geometric levelling, with an accuracy of 1 mm, allowed us to link the tidal marks with geodetic vertices located on Livingston and Deception islands. The amplitudes and phase lags obtained by harmonic analysis are compared to the harmonic constants of several coastal stations and co-tidal and co-range charts. Results show an evident influence of tides in the sea level signal, with a clear mixed semi-diurnal behaviour and a daily inequality between high and low waters. Measurements of salinity and temperature were made using electronic sensors. Results from this study showed that salinity and temperature were strongly influenced by tides. Seawater temperature varied in a manner that was consistent with the time series of residual bottom pressure.

Establishment of a geodetic network in Tenerife is the starting point for the use of GPS and other precise geodetic techniques in the support of the study of kinematics and their relation with island volcanic activity. This paper is focused on the characterization of volcanotectonic activity of Tenerife, to determine the geodynamic framework for volcanic surveillance. TEGETEIDE network, set up in 2005 and re-observed each year, is composed of seven GNSS–GPS stations scattered throughout the island. A horizontal deformation model is presented in order to explain the observed island displacement pattern in the geodynamic context of the Nubian plate. According to the models obtained, the most important geologic structures, such as the volcanic rifts and the caldera, determine the current deformation pattern of Tenerife. The geodynamics of the most stable areas of the island behave similarly to that observed from the permanent GNSS–GPS reference stations located in La Palma and Gran Canaria Islands. Anomalous geodynamic behaviour has been detected in two zones of Tenerife, which configure an NW–SE axis crossing the central sector of the island, related with the volcanotectonic activity of the island and its surroundings.

In recent years concerns have been growing in the scientific community over the definition of scientific responsibilities during emergencies, and the legal status of scientists involved in the corresponding decision-making. It is clear that the legal framework is one of the main elements affecting this issue; however, many factors may affect both the specific scientific decision-making and the definition of general scientific responsibilities. The situation will vary depending on the type and scale of emergency, and from place to place, even in the same country. There will be no such thing as a single, ideal solution. In the latest El Hierro volcanic crisis many factors have negatively affected the scientific management and have prevented an adequate definition of scientific responsibility. These factors have been detected and documented by the authors. They include excessive pressure due to human and economic issues, a poor legal framework with identifiable deficiencies, an Emergency Plan in which the Volcanic Activity/Alert Level (VAL), Emergency Response Level (ERL) and Volcanic Traffic Light (VTL) have been too rigidly linked, serious weaknesses in the management and structure of the Scientific Committee (SC), and more. Even though some of these problems have now been detected and certain solutions have already been proposed, the slowness and complexity of the bureaucratic processes are making it difficult to implement solutions., This research has been funded by the CSIC (201130E070) and MINECO (CGL2011-28682- C02-01) research projects.

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.

The purpose of this paper is to develop a new methodology for analyzing astronomical data, in particular, one of the light curves obtained in the PHEMU campaign in 1997, where the mutual phenomena between Jupiter and its satellites were observed from the Earth due to the coincidence of the equatorial plane of Jupiter and the orbit plane of the Earth. The more specific aim of this study is to determine the times of the beginning and the end of the phenomena, and the moment when the recorded light flux was at a minimum. The techniques we applied were based on the wavelet theory, which allows us to study a signal from its approximations and details at different scales. Before applying the designed algorithm to our experimental data, we considered a synthetic light curve in order to check the reliability of our method. It should be mentioned that the results are not relevant from the astronomical point of view, since no corrections for albedo or illumination were applied to the recorded data.

The processing of measurement data from satellite constellations such as Global Navigation Satellite Systems (GNSS), including the well-known Global Positioning System (GPS), have been successfully applied to virtually all areas of geophysical sciences. In this work, a method is described where Geographical Information Systems (GIS) are employed to build hourly ionospheric Total Electron Content (TEC) maps for 2011 over the southern Iberian Peninsula. The maps used GPS-derived geometryfree linear combinations attained from station data from the Algarve, Alentejo (Portugal), Andalusia, Murcia and Valencia (Spain) regions. Following the construction of the ionospheric maps, it was possible to relate these results to natural phenomena. The observed phenomena included diurnal and seasonal variations: daytime TEC maxima, nighttime TEC peaks, summer TEC value decreases, and spring and fall TEC maxima. After validation of these periodic phenomena, detection of non-periodic changes, such as solar flares and tectonic interactions with the ionosphere were attempted. The results showed a TEC increase following a selected solar flare event and a potential TEC build-up prior to the 2011 Lorca earthquake. Further studies could open up the possibility of building early warning systems. The presented methods, based on available software packages, are also of value in monitoring the effect of the ionosphere on radio signals, satellite and mobile communication, power grids, and for accurate GNSS navigation.

The 2011 volcanic unrest at El Hierro Island illustrated the need for a Volcanic Alert System (VAS) specifically designed for the management of volcanic crises developing after long repose periods. The VAS comprises the monitoring network, the software tools for analysis of the monitoring parameters, the Volcanic Activity Level (VAL) management, and the assessment of hazard. The VAS presented here focuses on phenomena related to moderate eruptions, and on potentially destructive volcano-tectonic earthquakes and landslides. We introduce a set of new data analysis tools, aimed to detect data trend changes, as well as spurious signals related to instrumental failure. When data-trend changes and/or malfunctions are detected, a watchdog is triggered, issuing a watch-out warning (WOW) to the Monitoring Scientific Team (MST). The changes in data patterns are then translated by the MST into a VAL that is easy to use and understand by scientists, technicians, and decision-makers. Although the VAS was designed specifically for the unrest episodes at El Hierro, the methodologies may prove useful at other volcanic systems.

Significant deformations, followed by increased seismicity detected since 2011 July at El Hierro, Canary Islands, Spain, prompted the deployment of additional monitoring equipment. The climax of this unrest was a submarine eruption first detected on 2011 October 10, and located at about 2 km SW of La Restinga, southernmost village of El Hierro Island. The eruption ceased on 2012 March 5, after the volcanic tremor signals persistently weakened through 2012 February. However, the seismic activity did not end with the eruption, as several other seismic crises followed. The seismic episodes presented a characteristic pattern: over a few days the number and magnitude of seismic event increased persistently, culminating in seismic events severe enough to be felt all over the island. Those crises occurred in 2011 November, 2012 June and September, 2012 December to 2013 January and in 2013 March- April. In all cases the seismic unrest was preceded by significant deformations measured on the island's surface that continued during the whole episode. Analysis of the available GPS and seismic data suggests that several magma displacement processes occurred at depth from the beginning of the unrest. The first main magma movement or 'injection' culminated with the 2011 October submarine eruption. A model combining the geometry of the magma injection process and the variations in seismic energy release has allowed successful forecasting of the new-vent opening. © The Authors 2014. Published by Oxford University Press on behalf of The Royal Astronomical Society.

El Hierro Island in the Canary Archipelago recently experienced a submerged eruption a few kilometers off its southern shore, detected 2011 October 10 on the island’s south-rift alignment. The seismic activity suddenly increased around mid 2011 July, and ground deformation was then detected on the only geodetic benchmark that is continuously observed by global navigation satellite systems techniques and provides public data access. Based on that information, several other global navigation satellite system signal receivers were deployed on the island to provide continuous observation. For data collected by these receivers, a processing strategy was applied to achieve millimeter-level half-hourly positioning solutions. Position updates every 24 h are satisfactory to determine tectonic-plates’ velocities. Updates near 1 s or less are required to characterize seismic waves. In between, minute-level updates are well suited for monitoring active volcano's inflation or deflation, providing an optimal time resolution of the local ground deformation. In half-hourly positioning solutions, the heterogeneous satellites’ distribution in their orbital planes gives different constraints during satellite-constellation revolution, which can bias the solutions. Also, several geophysical influences can bias the solutions, including those related to gravitational movements. These influences have mostly semi-diurnal periodicities and may be considered Gaussian colored noise on the position’s time series. Daily solutions that average out these influences can be applied in active volcanoes, but they can impose some limitations because they average the daily deformation, and the update waiting time is not suitable when near real-time surveillance is mandatory. These semi-diurnal biases do need to be removed or minimized to achieve millimeter-level sub-daily positioning solutions, however, and to do so, a discrete Kalman filter was applied to enhance the half-hourly positioning solutions required during El Hierro’s 2011–2012 unrest and eruption. Throughout El Hierro’s volcanic activity, there were correlations between ground deformation and seismic activity. Many times the deformation preceded the earthquakes, though at other times the seismic activity was followed by the ground deformation response. This correlation is the outcome of ground deformation taking place as the result of energy accommodation, whereas seismic events correspond to energy release. Hence, those observed correlations indicate that the Kalman filter-enhanced half-hourly positioning solutions measured local ground deformation accurately; they were not a mathematical "trick" producing a spurious precision.