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Long-period magnetotelluric (MT) monitoring after 2021 volcanic eruption (Cumbre Vieja, La Palma Island)_Time Series
No full textThis dataset contains:
- Raw time series recorded at a long-period MT site located on La Palma (Canary Islands) during and after the 2021 volcanic eruption.
- Figures showing the evolution of the time series and the resultant impedance tensor.
Time series are provided to support the results shown in the related publication. No Derivatives license
La Palma 2021 Eruption Dike Modeling
Get PDFTreballs Finals de Grau de Física, Facultat de Física, Universitat de Barcelona, Curs: 2024, Tutores: Perla Piña-Varas, Pilar QueraltMagnetotelluric surveying has a huge potential for studying subsurface structures and processes due to its wide range of depths. It is particularly useful in igneous and volcanic events due to the considerable resistivity changes that rock undergoes at high temperatures. Despite that, few models and simulations solving the temperature-resistivity evolution with time have been proposed.
The 2021 volcanic eruption in La Palma provided an excellent opportunity to develop a model of these characteristics given the constant monitoring and surveying data available of the periods during and after the eruption. The presence of electrical resistivity anomalies during the cooling process of the igneous intrusion made it even more interesting to develop a more complete and general model for these types of system
Gravity applied to La Garriga-Samalús geothermal system
Get PDFTreballs Finals de Grau de Física, Facultat de Física, Universitat de Barcelona, Curs: 2022, Tutores: Perla Piña-Varas, Gemma MitjanasGeophysics is a transverse science field which aims to explore and characterize the surface and subsurface of the Earth. There are different geophysical methods based on different physical parameters that can be applied in geological and geothermal exploration. In this work we apply the gravity method to the Vallès-Penedès Basin (NE of Spain), which is based on the density differences of the subsurface. In order to differentiate the basin of its surroundings we calculate the Bouguer anomaly of the area from the filtered acquisitioned data. Not only there is the Vallès Basin as an interesting geological item but also the Vall`es Fault, which we show using the horizontal derivative. We also do a gravity inversion-which gives the density in depth- tracing a profile along the basin in a NW-SE direction. The geological characterization of the area, and specifically, the characterization of the fault, is the first step for a better understanding of the geothermal syste
Gravity applied to La Garriga-Samalús geothermal system
No full textTreballs Finals de Grau de Física, Facultat de Física, Universitat de Barcelona, Curs: 2022, Tutores: Perla Piña-Varas, Gemma MitjanasGeophysics is a transverse science field which aims to explore and characterize the surface and subsurface of the Earth. There are different geophysical methods based on different physical parameters that can be applied in geological and geothermal exploration. In this work we apply the gravity method to the Vallès-Penedès Basin (NE of Spain), which is based on the density differences of the subsurface. In order to differentiate the basin of its surroundings we calculate the Bouguer anomaly of the area from the filtered acquisitioned data. Not only there is the Vallès Basin as an interesting geological item but also the Vall`es Fault, which we show using the horizontal derivative. We also do a gravity inversion-which gives the density in depth- tracing a profile along the basin in a NW-SE direction. The geological characterization of the area, and specifically, the characterization of the fault, is the first step for a better understanding of the geothermal syste
ERT applied to the study of saltwater intrusion
Get PDFTreballs Finals de Grau de Física, Facultat de Física, Universitat de Barcelona, Curs: 2022, Tutores: Perla Piña-Varas, Pilar Queralt CapdevilaSea water intrusion, or saltwater intrusion (SWI) is a common phenomenon in coastal aquifers. With electrical resistivity tomography (ERT) method, a region’s subsoil can be characterized, leading to pseudo-section maps that allow to differentiate between freshwater and saltwater cavities. In this study, ERT method was applied in the Riera de Sant Pol de Mar, in two different surveys a month apart; which permitted to measure a strong variation between both and track the aquifer’s underground evolution. This allowed the observation and analysis of the seawater intrusion phenomenon. If combined with additional methods or information, a better understanding of the diverse processes that occur beneath the aquifer’s surface could be achieve
Aplicación del método magnetotelúrico a la caracterización de reservorios: Anticlinal de El Hito (Cuenca) y Sistema Geotérmico de Tenerife
Get PDFEl método magnetotelúrico es una técnica geofísica que permite caracterizar las estructuras del subsuelo en base a la distribución de la resistividad eléctrica.
Este parámetro físico es muy sensible a pequeños cambios en la composición de un determinado volumen de roca, por lo que estará fuertemente condicionado por factores como la naturaleza y composición de la roca, la porosidad, la proporción de poros saturados, las características del fluido de saturación, la presión o la temperatura. Este hecho hace que su caracterización sea especialmente atractiva durante la etapa de exploración de reservorios geológicos.
De entre los métodos electromagnéticos, la magnetotelúrica destaca por ser el único capaz de aportar información sobre las características del subsuelo a profundidades de varios kilómetros. Por esta razón, será el único método electromagnético aplicable al estudio de reservorios profundos, como son por ejemplo, la mayoría de los sistemas geotérmicos, los posibles almacenes geológicos de CO2 o los acuíferos profundos.
En esta tesis se presentan los modelos geoeléctricos obtenidos del estudio de dos reservorios geológicos distintos: un posible almacén geológico de CO2 (Anticlinal de El Hito, Cuenca) y un sistema geotérmico convencional (Tenerife, Islas Canarias). Asimismo, se analiza y se expone la metodología empleada para la correcta caracterización de cada una de las estructuras.
Los resultados obtenidos son significativos y aportan información relevante sobre la morfología y localización de estructuras tan importantes como son, según el caso, el sello de los reservorios, posibles fallas o posibles cámaras magmáticas.
Adicionalmente, se ha realizado en ambos casos un análisis de la respuesta magnetotelúrica de las estructuras. Así, cada estudio aporta además información sobre la metodología de inversión empleada para obtener resultados válidos y satisfactorios.
Esta tesis supone, para el caso del estudio del sistema geotérmico de Tenerife, la primera etapa de los trabajos a realizar. El modelo aquí presentado, ha sido interpretado en el contexto de un sistema geotérmico y comparado con otros modelos geofísicos y geológicos. Aún así, y teniendo en cuanta la cantidad y la variedad de los estudios que se han llevado a cabo en la isla de Tenerife (geoquímica, geofísica, geología), será necesario, para extraer toda la información que el modelo puede aportar, examinar el modelo de resistividades conjuntamente con la información que no ha podido ser incluida en este trabajo.The magnetotelluric method (MT) uses naturally occurring electromagnetic field variations as a source for imaging the electrical resistivity structure of the earth.
Electrical resistivity is a physical property dominated by the presence of minor phases in the host rock matrix, so it will be strongly influenced by factors such as the nature and composition of the rock, the porosity, the proportion of saturated pore fluid characteristics of saturation, pressure or temperature. This characterization makes it especially attractive during the exploration stage of geological reservoirs.
Among electromagnetic methods, magnetotelluric is the only one able to provide information about the characteristics of the subsoil at depths of several kilometres. Therefore, MT is the suitable electromagnetic method for the study of deep reservoirs, such as geothermal systems, CO2 geological reservoirs or deep aquifers.
In this thesis the MT method has been applied to characterize the geoelectrical structures below two different reservoirs: a potential CO2 geological reservoir (El Hito Anticline, Cuenca, Spain) and a conventional geothermal system (Tenerife, Canary Islands). In addition, a comprehensive analysis of the methodology used for obtain a suitable geoelectrical model of each structure is exposed.
The results obtained are significant and provide relevant information on the morphology and location of the most important structures, such as the seal, faults or the magma chambers.
Moreover, an analysis of the magnetotelluric response of each structure has been carried out. Thus, each study provides information about the inversion methodology used to obtain valid and satisfactory results.
In the case of the Tenerife geothermal system study, this thesis is the first stage of the work to be carried. The resistivity model presented here has been interpreted in the context of a geothermal system and compared with other geophysical and geological models. Nevertheless, and taking into account the number and variety of studies have been conducted on the island of Tenerife (geochemistry, geophysics, geology), it is necessary review the resistivity model jointly with that information that could not be included in this work
La Maladeta Broad Band Magnetotellurics (BBMT) data (Axial/South Pyrenean Zone)
No full textThis dataset contain the broad band magnetotelluric (BBMT) data collected in the limit between the Axial and the South Pyrenean Zones along two different surveys (2006 the southern part of the profile and in 2019, the northern one). The study is focused on understanding the geometry at depth of La Maladeta batholit and surrounding area, since fundamental questions remain unclear about the basement and cover architecture, the geometry at depth of significant bodies as the Late Variscan intrusive granites and/or Triassic evaporitic accumulations in this part of the Pyrenees
Long-period magnetotelluric (MT) monitoring after 2021 volcanic eruption (Cumbre Vieja, La Palma Island)
No full textThis datasets contains:
Selected EDI files obtained from a time series recorded after the 2021 volcanic eruption (more than fourteen months length). The original time series was divided and processed into segments of ten days each. This segmentation resulted in a set of forty-five MT curves named LP1 to LP45.
Models resultant from the logarithmic difference between one 3-D resistivity model and the subsequent one.
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Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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