PlatEMotion: a Matlab® Tool for Geodetic Reference Frame Definition

An important concept related to plate tectonics theory is the internal rigidity of tectonic plates together with Euler’s theorem, which allows modelling the relative motion of plates quantitatively. Roughly speaking, plates can be viewed as rigid caps on the surface of a sphere. The motion of a plate on a sphere can be described by a rotation about a virtual axis that passes through the centre of the sphere (Euler’s theorem). This implies that an angular velocity vector originating at the centre of the Earth can describe motions of plates. The most widespread parameterization of such a vector is using latitude and longitude to describe the location where the rotation axis cuts the surface of the Earth, and a rotation rate that corresponds to the magnitude of the angular velocity. Formally, the latitude and longitude of the angular velocity vector constitute the so called ‘Euler pole’. Here, we describe the main features of the developed software tool, called PlatE-Motion (PEM), which allows calculating both the expected velocity value for any point located on the Earth providing a Euler pole (direct problem) and inferring the Euler pole parameters by inverting the observed velocities at a set of sites located on a rigid block (inverse problem). PEM is developed in Matlab® framework and is designed for easy-to-use file exchange with the GAMIT/GLOBK software package [Herring et al., 2006], and has a user-friendly graphical user interface (GUI). The file formats of the data used by PEM are not only restricted to the GAMIT/GLOBK file formats, but they can also be simple ASCII files generated from other kind of software. The tool is available for the scientific community. The interested user can freely obtain it by simply contacting the author

3D displacement field retrieved by integrating Sentinel-1 InSAR and GPS data: the 2014 South Napa earthquake

In this study the integration of Sentinel-1 InSAR (Interferometric Synthetic Aperture Radar) and GPS (Global Positioning System) data was performed to estimate the three components of the ground deformation field due to the Mw 6.0 earthquake occurred on August 24th, 2014, in the Napa Valley, California, USA. The SAR data were acquired by the Sentinel-1 satellite on August 7th and 31st respectively. In addition, the GPS observations acquired during the whole month of August were analyzed. These data were obtained from the Bay Area Regional Deformation Network, the UNAVCO and the Crustal Dynamics Data Information System online archives. The data integration was realized by using a Bayesian statistical approach searching for the optimal estimation of the three deformation components. The experimental results show large displacements caused by the earthquake characterized by a predominantly NW-SE strike-slip fault mechanism.The research has been supported by the “Marco Polo” project by the University of Bologna (UNIBO), the Spanish Ministry of Economy and Competitiveness research project ESP2013-47780-557 C2-1-R and the EU 7th FP MED-SUV project (contract 308665).Peer reviewe

Geodetic Deformation versus Seismic Crustal Moment-Rates: Insights from the Ibero-Maghrebian Region

Seismic and geodetic moment-rate comparisons can reveal regions with unexpected potential seismic hazards. We performed such a comparison for the Southeastern Iberia—Maghreb region. Located at the western Mediterranean border along the Eurasia–Nubia plate convergence, the region has been subject to a number of large earthquakes (M ≥ 6.5) in the last millennium. To this end, on the basis of available geological, tectonic, and seismological data, we divided the study area into twenty-five seismogenic source zones. Many of these seismogenic source zones, comprising the Western Betics, the Western Rif mountains, and the High, Middle, and Saharan Atlas, are characterized by seismic/geodetic ratio values lower than 23%, evidencing their prevailing aseismic behavior. Intermediate seismic/geodetic ratio values (between 35% and 60%) have been observed for some zones belonging to the Eastern Betics, the central Rif, and the Middle Atlas, indicating how crustal seismicity accounts only for a moderate fraction of the total deformation-rate budget. High seismic/geodetic ratio values (> 95%) have been observed along the Tell Atlas, highlighting a fully seismic deformation

Algunos datos para la monitorización del acuífero Alto Guadalentín

En el presente artículo se presentan un análisis de series temporales de datos relativos a la evolución niveles piezométricos de la zona del Alto del Guadalentín (Murcia) y un análisis paralelo de series temporales de datos GNSS referentes a las altitudes de la zona. El objetivo de este análisis pretende establecer posibles correlaciones entre la subsidencia recogida por la red de estaciones GPS nacionales y el aumento de la profundidad piezométrica a la que se encuentran los acuíferos. Este objetivo se desarrollará mediante el análisis de los niveles piezométricos en comparación con las diferencias de altitud registradas en estaciones GNSS nacionales

Geodetic Study of the 2006–2010 Ground Deformation in La Palma (Canary Islands): Observational Results

La Palma is one of the youngest of the Canary Islands, and historically the most active. The recent activity and unrest in the archipelago, the moderate seismicity observed in 2017 and 2018 and the possibility of catastrophic landslides related to the Cumbre Vieja volcano have made it strongly advisable to ensure a realistic knowledge of the background surface deformation on the island. This will then allow any anomalous deformation related to potential volcanic unrest on the island to be detected by monitoring the surface deformation. We describe here the observation results obtained during the 2006–2010 period using geodetic techniques such as Global Navigation Satellite System (GNSS), Advanced Differential Synthetic Aperture Radar Interferometry (A-DInSAR) and microgravimetry. These results show that, although there are no significant associated variations in gravity, there is a clear surface deformation that is spatially and temporally variable. Our results are discussed from the point of view of the unrest and its implications for the definition of an operational geodetic monitoring system for the islan

3D Multi-source Model of Elastic Volcanic Ground Deformation

Developments in Interferometric Synthetic Aperture Radar (InSAR) and GNSS (Global Navigation Satellite System) during the past decades have promoted significant advances in geosciences, providing high-resolution ground deformation data with dense spatio-temporal coverage. This large dataset can be exploited to produce accurate assessments of the primary processes occurring in geologically active areas. We present a new, original methodology to carry out a multi-source inversion of ground deformation data to better understand the subsurface causative processes. A nonlinear approach permits the determination of location, size and three-dimensional configuration, without any a priori assumption as to the number, nature or shape of the potential sources. The proposed method identifies a combination of pressure bodies and different types of dislocation sources (dip-slip, strike-slip and tensile) that represent magmatic sources and other processes such as earthquakes, landslides or groundwater-induced subsidence through the aggregation of elemental cells. This approach has the following features: (1) simultaneous inversion of the deformation components and/or line-of-sight (LOS) data; (2) simultaneous determination of diverse structures such as pressure bodies or dislocation sources, representing local and regional effects; (3) a fully 3D context; and (4) no initial hypothesis about the number, geometry or types of the causative sources is necessary. This methodology is applied to Mt. Etna (Southern Italy). We analyze the ground deformation field derived from a large InSAR dataset acquired during the January 2009 &ndash; June 2013 time period. The application of the inversion approach models several interesting buried structures as well as processes related to the volcano magmatic plumbing system, local subsidence within the Valle del Bove and seaward motion of eastern flank of the volcano. </div

A multi-sensor approach for coastal area monitoring

This study proposes a multi-sensor approach to promote and effective coastal area monitoring strategy over areas that include critical infrastructures, e.g.; on-shore and off-shore oil/gas extraction platforms and groundwater reservoirs. The monitoring strategy includes both sea-side and land-side observations using remotely sensed measurements. With respect to the land-side, multi-temporal differential Interferometric Synthetic Aperture Radar (DInSAR) and Global Positioning System (GPS) techniques are exploited to monitor of subsidence phenomena along on-shore hydrocarbon and groundwater reservoirs, where surface deformations can be correlated to the extraction / pumping of resources from / into the subsoil. This is a non-trivial issue, which aims at improving the standards of security for the production / exploitation / storage of underground resources, as well as providing / implementing ad-hoc procedures for the monitoring of interested. With respect to the sea-side, effective SAR techniques are exploited to take benefit of multi-polarization SARs to observe oil/gas rigs/platforms and to observe oil discharges close to the oil extraction sites.PublishedCopenaghen, Denmark7A. Geofisica per il monitoraggio ambientale e geologia medic

Detection of the volcanic unrest onset on La Palma Island, Canary Islands, and study of its time evolution

[EN] The island of La Palma is one of those with the highest potential risk in the Canary archipelago, therefore it is important to carry out an in-depth study to define its state of volcanic activity. This has been done using satellite radar observations and a state-of-the-art original interpretation technique. Both things have made it possible to detect the beginning of the volcanic reactivation on the island of La Palma, probably decades before a possible eruption. Its temporal evolution shows a changing spatial and temporal nature of volcanic deformation with great spatial resolution and over a prolonged period of time (2009-2020), providing information on the dynamic nature of the associated processes. The geodetic techniques used allow detecting the fluid migration induced by the injection of magma in depth and identifying the existence of dislocation sources under the Cumbre Vieja volcano that could be associated with future landslides, making it necessary to continue with the monitoring of this reactivation process using these and other techniques.[ES] La isla de La Palma es de las de mayor riesgo potencial del archipiélago canario, siendo por tanto importante realizar un estudio en profundidad que permita definir su estado de actividad volcánica. Esto se ha realizado usando observaciones radar de satélite y una técnica de interpretación original de última generación. Ambas cosas han permitido detectar el inicio de la reactivación volcánica en la isla de La Palma, probablemente décadas antes de una posible erupción. Su evolución temporal muestra una naturaleza cambiante de la deformación volcánica, tanto espacial como temporalmente. El uso de imágenes radar permite obtener resultados con una gran resolución espacial y en un periodo de tiempo prolongado (2009-2020), obteniendo información sobre la naturaleza dinámica de los procesos asociados. Las técnicas geodésicas empleadas permiten detectar la migración de fluidos inducida por la inyección de magma en profundidad e identificar la existencia de fuentes de dislocación bajo el volcán Cumbre Vieja que podrían estar asociadas con futuros deslizamientos, siendo por tanto necesario continuar con la monitorización de este proceso de reactivación utilizando estas y otras técnicas.Esta investigación ha sido financiada por el proyecto de investigación DEEP-MAPS (RTI2018-093874-B-100) del Ministerio de Ciencia, Innovación y Universidades. También ha sido parcialmente financiado por el proyecto del CSIC 201530E019, el proyecto GEOSIR (AYA2010-17448) del Ministerio de Ciencia e Innovación y el proyecto del MINECO CGL2017-86241-R. Agradecemos a DARES S.L por la licencia de uso del software interferométrico CPT en este studio. Este trabajo representa una contribución a la plataforma interdisciplinar del CSIC PTI TELEDETECT.Escayo, J.; Fernández, J.; Hu, Z.; Camacho, A.; Samsonov, S.; Prieto, J.; Tiampo, K.... (2021). Detección del inicio de reactivación volcánica en la isla de La Palma, Islas Canarias, y estudio de su evolución temporal. En Proceedings 3rd Congress in Geomatics Engineering. Editorial Universitat Politècnica de València. 155-162. https://doi.org/10.4995/CiGeo2021.2021.12746OCS15516

Shallow magmatic intrusion evolution below La Palma before and during the 2021 eruption

La Palma, Canary Islands, underwent volcanic unrest which culminated in its largest historical eruption. We study this unrest along 2021 using Interferometric Synthetic Aperture Radar (InSAR) and a new improved interpretation methodology, comparing achieved results with the crustal structure. We reproduce the final phase of La Palma volcanic unrest, highligthing a shallow magma accumulation which begins about 3.5 months before the eruption in a crustal volume charactherized by low density and fractured rocks. Our modeling, together with our improved pictures of the crustal structure, allows us to explain the location and characteristics of the eruption and to detect failed eruption paths. These can be used to explain post-eruptive phenomena and hazards to the local population, such as detected gases anomalies in La Bombilla and Puerto Naos. Our results have implications for understanding volcanic activity in the Canaries and volcano monitoring elsewhere, helping to support decision-making and providing significant insights into urban and infrastructure planning in volcanic areas

Application of multi-sensor advanced DInSAR analysis to severe land subsidence recognition: Alto Guadalentín Basin (Spain)

Multi-sensor advanced DInSAR analyses have been performed and compared with two GPS station measurements, in order to evaluate the land subsidence evolution in a 20-year period, in the Alto Guadalentín Basin where the highest rate of man-induced subsidence (> 10 cm yr−1) of Europe had been detected. The control mechanisms have been examined comparing the advanced DInSAR data with conditioning and triggering factors (i.e. isobaths of Plio-Quaternary deposits, soft soil thickness and piezometric level).This work is financially supported by the DORIS project (Ground Deformation Risk Scenarios: an Advanced Assessment Service) funded by the EC-GMES-FP7 initiative (Grant Agreement 423 no. 242212). ALOS PALSAR images were provided by the project JAXA-1209. Part of this work is supported by the Spanish Government under project TEC2011-28201-C02-02 and TIN2014-55413-C2-2-P and by the project 15224/PI/10 from the Regional Agency of Science and Technology in Murcia. Additional funding was obtained from the Spanish Research Program through the projects AYA2010-17448, ESP2013-47780-C2-1-R and ESP2013-47780-C2-2-Rand by the Ministry of Education, Culture and Sport through the project PRX14/00100