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This manuscript describes the design, development, and implementation of a prototype system based on seismogeodetic techniques, consisting of a low-cost MEMS seismometer/accelerometer, a biaxial inclinometer, a multi-frequency GNSS receiver, and a meteorological sensor, installed at the Doñana Biological Station (Huelva, Spain) that transmits multiparameter data in real and/or deferred time to the control center at the University of Cadiz. The main objective of this system is to know, detect, and monitor the tectonic activity in the Gulf of Cadiz region and adjacent areas in which important seismic events occur produced by the interaction of the Eurasian and African plates, in addition to the ability to integrate into a regional early warning system (EWS) to minimize the consequences of dangerous geological phenomena.

Abstract 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.

The tectonic activity produced by the interaction between the Eurasian and African plates continually generates high seismic activity and the possibility of tsunamis occurring in the Gulf of Cadiz, Spain. The occurrence of these phenomena and the associated threat implies the need to implement a seismogeodesic system made up of a GNSS receiver, a seismograph–accelerograph, and an inclinometer that allows for us to study the behavior of tectonic activity in the Gulf and adjacent areas. This system is installed in the Doñana biological station, Huelva, Spain, and sends continuous records to the control center located in the University of Cadiz, generating GNSS, seismic, accelerometric, and inclinometric time series, which, together with the implementation of geodetic and geophysical techniques, is capable of providing information on tectonic activity immediately. In this manuscript, the time series generated by the system have been analyzed, in addition to a specific seismic event that occurred in the study area.

The signal coming from the artificial satellites of the GNSS system suffers various effects that considerably decrease the precision in solving the positioning problem. To mathematically model these effects, the atmosphere is divided into two main parts, the troposphere and the ionosphere. The troposphere can only be modelled, while the ionospheric effect can be modeled or eliminated depending on the geodetic sophistication of the receivers used. In this way, information is obtained about both layers of the atmosphere. For tropospheric modeling, the parameters of total zenithal delay (ZTD) or precipitable water vapor (PVW) will be taken, and for the ionosphere the total electron content (TEC) will be taken. In this work, statistical and analytical techniques will be applied with the R software; for example, ARMA, ARIMA models, least squares methods, wavelet functions, Kalman techniques, and CATS analysis. With this, the anomalies that occurred in the values of the ZTD and TEC in the case of the 2021 eruption of the Cumbre Vieja volcano on the island of La Palma.

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 frequency time series, whose analysis provides knowledge of the tectonic or volcanic geodynamic activity of a region. In this work, a GNSS time series study is 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 are studied; for example, ARMA, ARIMA models, least-squares methods, wavelet functions, Kalman techniques and CATS analysis. To obtain a geodynamic model of the Central American region, the horizontal and vertical velocities obtained by applying the above methods are taken, choosing the velocity with the least margin of error. Significant GNSS time series are obtained in geodynamically active regions (tectonic and/or volcanic).

The region defined by the South Shetland Islands, Bransfield Sea, and Antarctic Peninsula has complex geodynamic activity resulting from the active subduction process of the Phoenix Plate under the Antarctic Plate. This subduction produces a rift of expansion along the Bransfield Sea basin between the South Shetland Islands and the Antarctic Peninsula. There is also a chain of submarine (Orca, Three Sisters, and Building A) and emerged (Deception and Pinguin) volcanoes. In 2020, there was intense seismic activity around the Orca volcano with earthquakes of up to 6.9 Mw. This paper presents displacement models of this seismic activity produced in the region. The geodetic time series of the GNSS stations located in the region were analyzed: UYBA at the Uruguayan Artigas Antarctic Base (King George Island) and PAL2 at the U.S. Palmer Antarctic Base (Anvers Island). These data were taken from the Nevada Geodetic Laboratory.

Aerial frames and satellite imagery are widely recognized data sources from which to produce maps. For volcanoes, maps enable the quantification of erupted ash and the destruction caused. The last eruptive sequence on Deception Island was endured from 1967 to 1970. Analogue maps were produced via classical photogrammetric methods with a high degree of human intervention mainly to analyse the volcanic-centres areas only. However, historical aerial frames cover the whole of Deception Island. Structure from motion photogrammetry, a near-automated compilation of digital image processing strategies, minimizes the degree of human intervention to produce orthographic mosaics and digital elevation models from digital aerial frames. Orthographic mosaics were produced from historical aerial frames of 1956 and 1968, and a Kompsat-3 image of 2020. Their shared root-mean-square deviation was 1.8 m and 1.7 m in easting and northing, respectively, at ground control points measured with phase-differential global navigation satellite systems. The digital elevation models were processed with a root-mean-square deviation of 2.3 m and 3.6 m from 1956 and 1968 aerial frames, respectively. As the first application, erupted ashfall and the subsequent destruction, mainly at the former Chilean and British bases, were identified, and the volume of erupted ash was assessed to be over 0.16 km3 within the area mapped by these new digital cartographic products.

Abstract 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).

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.

La base de datos de la Red Hidrométrica de la Armada Boliviana (RHAB) carecía de la agilidad de consulta, por lo que precisa de un moderno gestor de información espacial y de base de datos para la optimización del manejo de los recursos hidrológicos. Por ello, se presenta una nueva metodología, generalizable a cualquier país, para desarrollar un sistema multidisciplinario de información geográfico (SIG) en Internet. Es de fácil e intuitiva utilización, orientado a la gestión de información hidrométrica para alerta temprana, apoyo a la navegación, al transporte fluvial y lacustre, para proyectos y obras de investigación, ingeniería, cartografía, pesca y turismo, entre otros. El acceso a la base de datos geográfica que contiene la información hidrológica se realiza mediante Internet, con un visor web geográfico. Se han integrado diferentes aplicaciones de software de distribución libre, junto con diversos lenguajes de programación. La disposición inmediata de datos precisos coadyuva en la prevención de desastres por inundaciones.

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.

This paper describes the development of a multi-parameter system for monitoring volcanic activity. The system permits the remote access and the connection of several modules in a network. An embedded ARMTM processor has been used, allowing a great flexibility in hardware configuration. The use of a complete Linux solution (DebianTM) as Operating System permits a quick, easy application development to control sensors and communications. This provides all the capabilities required and great stability with relatively low energy consumption. The cost of the components and applications development is low since they are widely used in different fields. Sensors and commercial modules have been combined with other self-developed modules. The Modular Volcano Monitoring System (MVMS) described has been deployed on the active Deception Island (Antarctica) volcano, within the Spanish Antarctic Program, and has proved successful for monitoring the volcano, with proven reliability and efficient operation under extreme conditions. In another context, i.e., the recent volcanic activity on El Hierro Island (Canary Islands) in 2011, this technology has been used for the seismic equipment and GPS systems deployed, thus showing its efficiency in the monitoring of a volcanic crisis.