Search

Your search keyword '"Marcuello, Alex"' showing total 28 results
Start Over Author "Marcuello, Alex" Search Limiters Available in Library Collection
28 results on '"Marcuello, Alex"'

4. Expected Geomagnetically Induced Currents in the Spanish islands power transmission grids from extreme geomagnetic observatory field variations

Author

Torta, J. Miquel, Marsal, Santiago, Piña-Varas, Perla, Hafizi, Raha, Martí, Anna, Campanyà, Joan, Canillas-Pérez, Victoria, Curto, Juan José, Ledo, Juanjo, Queralt, Pilar, and Marcuello, Alex

Abstract

Critical infrastructures on which society depends are affected by what are known as geomagnetically induced currents. As a consequence of Faraday's law of induction, which is associated with time variations of the magnetic field, an electromotive force is induced in the conductive earth. The (geo)electric field generated in this way acts as a voltage source through the power transmission networks, so that the induced currents during large geomagnetic storms can damage the transformers where the circuit is grounded. Many countries, such as Spain, have undertaken studies aimed at assessing the vulnerability of their power grids to the danger posed by this phenomenon, but one question that remained open was whether the grids that transmit power across their islands deserve attention. We have constructed models for the grids in each of the individual systems and used resistivity models of the lithosphere for each group of islands, from which we have calculated the surface impedances. The respective models of electrical admittances of the grids have been combined with the geoelectric field derived from the convolution of the recorded (or expected in an extreme scenario) geomagnetic storms and the impedances calculated from the geoelectrical models to derive the expected GICs in the power lines, substations, and transformers. The results of our study show that the vulnerability of the Canary Islands is very low, while that of the Balearic Islands is not negligible., The 28th IUGG General Assembly (IUGG2023) (Berlin 2023)

Published
2023

5. Magnetotelúrica aplicada a la exploración geotérmica profunda: Islas Canarias.

Author

Piña-Varas, Perla, Ledo, Juanjo, Queralt, Pilar, Marcuello, Alex, Mitjanas, Gemma, and Martínez Van Dorth, David

Abstract

Copyright of Boletín Geológico y Minero is the property of Instituto Tecnologico Geominero De Espana and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Published
2023
Full Text
View/download PDF

9. Time-lapse cross-hole electrical resistivity tomography (CHERT) for monitoring seawater intrusion dynamics in a Mediterranean aquifer

Author

Palacios, Andrea, primary, Ledo, Juan José, additional, Linde, Niklas, additional, Luquot, Linda, additional, Bellmunt, Fabian, additional, Folch, Albert, additional, Marcuello, Alex, additional, Queralt, Pilar, additional, Pezard, Philippe A., additional, Martínez, Laura, additional, del Val, Laura, additional, Bosch, David, additional, and Carrera, Jesús, additional

Published
2020
Full Text
View/download PDF

15. Resultados preliminares en la caracterización geométrica 3D de un litosoma arenoso de progradación deltaica mediante georadar (GPR) (Fm. Arenisca de Roda, Eoceno, Cuenca de Graus-Tremp)

Author

Coll, Miquel, López Blanco, M., and Marcuello, Alex

Subjects
Progradation, Topography, GPR, 3D geometry, Deltas
Abstract

A set of GPR profiles have been recorded in order to determine the 3D geometry of a prograding delta-front sandbody (Roda sandstone formation, Eocene, Graus-Tremp basin). Common Mid Points (CMP) also have been recorded to obtain the velocity of the electromagnetic wave in ground. In order to build the top surface of a 3D prism a set of topographic points have been acquired. Most of the GPR profiles are oriented parallel to the progradation direction (NNE-SSW) and show the expected geometries. The 3D prism has been built from the individual profiles, which shows the three dimensional geometry of the sandy lithosome

Published
2006

16. Architectural characterization of a delta-front reservoir analogue combining Ground Penetrating Radar and Electrical Resistivity Tomography: Roda Sandstone (Lower Eocene, Graus-Tremp basin, Spain)

Author

Coll, M., López Blanco, Miguel, Queralt, P., Ledo, J., Marcuello, Alex, Coll, M., López Blanco, Miguel, Queralt, P., Ledo, J., and Marcuello, Alex

Abstract

Three-dimensional reconstruction of reservoir analogues can be improved combining data from different geophysical methods. Ground Penetrating Radar (GPR) and Electrical Resistivity Tomography (ERT) data are valuable tools, since they provide subsurface information from internal architecture and facies distribution of sedimentary rock bodies, enabling the upgrading of depositional models and heterogeneity reconstruction. The Lower Eocene Roda Sandstone is a well-known deltaic complex widely studied as a reservoir analogue that displays a series of sandstone wedges with a general NE to SW progradational trend. To provide a better understanding of internal heterogeneity of a 10m-thick progradational delta-front sandstone unit, 3D GPR data were acquired. In addition, common midpoints (CMP) to measure the sandstone subsoil velocity, test profiles with different frequency antennas (25, 50 and 100MHz) and topographic data for subsequent correction in the geophysical data were also obtained. Three ERT profiles were also acquired to further constrain GPR analysis. These geophysical results illustrate the geometry of reservoir analogue heterogeneities both depositional and diagenetic in nature, improving and complementing previous outcrop-derived data. GPR interpretation using radar stratigraphy principles and attributes analysis provided: 1) tridimensional geometry of major stratigraphic surfaces that define four units in the GPR Prism, 2) image the internal architecture of the units and their statistical study of azimuth and dips, useful for a quick determination of paleocurrent directions. These results were used to define the depositional architecture of the progradational sandbody that shows an arrangement in very-high-frequency sequences characterized by clockwise paleocurrent variations and decrease of the sedimentary flow, similar to those observed at a greater scale in the same system. This high-frequency sequential arrangement has been attributed to the autocyclic d

Published
2013

17. Architectural characterization of a delta-front reservoir analogue combining Ground Penetrating Radar and Electrical Resistivity Tomography: Roda Sandstone (Lower Eocene, Graus-Tremp basin, Spain)

Author

Ledo Fernández, Juan José, Marcuello, Alex, Queralt, P., Coll, M., López Blanco, Miguel, Ledo Fernández, Juan José, Marcuello, Alex, Queralt, P., Coll, M., and López Blanco, Miguel

Abstract

Three-dimensional reconstruction of reservoir analogues can be improved combining data from different geophysical methods. Ground Penetrating Radar (GPR) and Electrical Resistivity Tomography (ERT) data are valuable tools, since they provide subsurface information from internal architecture and facies distribution of sedimentary rock bodies, enabling the upgrading of depositional models and heterogeneity reconstruction. The Lower Eocene Roda Sandstone is a well-known deltaic complex widely studied as a reservoir analogue that displays a series of sandstone wedges with a general NE to SW progradational trend. To provide a better understanding of internal heterogeneity of a 10m-thick progradational delta-front sandstone unit, 3D GPR data were acquired. In addition, common midpoints (CMP) to measure the sandstone subsoil velocity, test profiles with different frequency antennas (25, 50 and 100MHz) and topographic data for subsequent correction in the geophysical data were also obtained. Three ERT profiles were also acquired to further constrain GPR analysis. These geophysical results illustrate the geometry of reservoir analogue heterogeneities both depositional and diagenetic in nature, improving and complementing previous outcrop-derived data. GPR interpretation using radar stratigraphy principles and attributes analysis provided: 1) tridimensional geometry of major stratigraphic surfaces that define four units in the GPR Prism, 2) image the internal architecture of the units and their statistical study of azimuth and dips, useful for a quick determination of paleocurrent directions. These results were used to define the depositional architecture of the progradational sandbody that shows an arrangement in very-high-frequency sequences characterized by clockwise paleocurrent variations and decrease of the sedimentary flow, similar to those observed at a greater scale in the same system. This high-frequency sequential arrangement has been attributed to the autocyclic d

Published
2013

22. A new methodology to estimate magnetotelluric (MT) tensor relationships: Estimation of Local transfer-functIons by Combining Interstation Transfer-functions (ELICIT).

Author

Campanyà, Joan, Ledo, Juanjo, Queralt, Pilar, Marcuello, Alex, and Jones, Alan G.

Subjects
MAGNETOTELLURIC prospecting, TRANSFER functions, ESTIMATION theory, CALCULUS of tensors, TENSOR fields, MAGNETIC fields
Abstract

A new methodology to estimate magnetotelluric (MT) tensor relationships, called Estimation of Local transfer-functIons by Combining Interstation Transfer-functions (ELICIT), is proposed whereby the MT tensor relationships of the local site are derived using only interstation transfer functions. The MT impedance tensor and the geomagnetic transfer function at the local site are characterised by combining interstation tensor relationships between electric and magnetic fields at the local site with the horizontal magnetic fields acquired at a neighbouring site. The main property of the proposed method is that the employed interstation transfer functions are independently constrained, without the need to acquire the electric and the magnetic fields at the local site simultaneously to recover the local MT tensor relationships. Due to this property, the ELICIT method offers new possibilities for MT data acquisition and processing, providing significant improvements when the magnetic time-series at the local site are affected by local noise or are truncated. Error analysis shows that, even when magnetic fields are truncated, the quality of the results obtained following the ELICIT method are similar to those we would obtain if the magnetic fields had not been truncated. Another important property is that different neighbouring sites can be used to recover the tensor relationships at the local site. Averaging of results obtained using different neighbouring sites can be performed to improve the statistics. For our example data, when the ELICIT method is used to improve the statistics, errors of the estimates for periods between 1000 and 20 000 s periodicities are clearly reduced. All interstation transfer functions are calculated doing remote reference and the bootstrap method is used to compute the errors, when necessary. Long period magnetotelluric data acquired in the Pyrenees and in the Atlas Mountains in Morocco, and magnetic data provided by Fürstenfeldbruck magnetic observatory have been used to test the proposed ELICIT method, with positive results. Due to the lack of requirement that the electric and the magnetic fields of the local site be acquired simultaneously, the proposed method also offers new possibilities for MT data acquisition, optimizing the available instrumentation. [ABSTRACT FROM PUBLISHER]

Published
2014
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results