2024-03-29T15:37:02Zhttp://digital.csic.es/dspace-oai/requestoai:digital.csic.es:10261/1789602021-04-07T10:43:21Zcom_10261_39226com_10261_8col_10261_42742
Gómez-Ortiz, David
Blanco-Montenegro, Isabel
Arnoso, José
Martin-Crespo, Tomas
Solla, Mercedes
Montesinos, Fuensanta G.
Vélez, Emilio
Sánchez, Nieves
2019-03-29T19:44:15Z
2019-03-29T19:44:15Z
2019-03-21
Remote Sensing 11(6): 675 (2019)
2072-4292
http://hdl.handle.net/10261/178960
10.3390/rs11060675
http://dx.doi.org/10.13039/501100003329
http://dx.doi.org/10.13039/501100003339
http://dx.doi.org/10.13039/501100000780
Convective hydrothermal systems have been extensively studied using electrical and electromagnetic methods given the strong correlation between low conductivity anomalies associated with hydrothermal brines and high temperature areas. However, studies addressing the application of similar geophysical methods to hot dry rock geothermal systems are very limited in the literature. The Timanfaya volcanic area, located on Lanzarote Island (Canary Islands), comprises one of these hot dry rock systems, where ground temperatures ranging from 250 to 605 °C have been recorded in pyroclastic deposits at shallow (<70 m) depths. With the aim of characterizing the geophysical signature of the high ground temperature areas, three different geophysical techniques (ground penetrating radar, electromagnetic induction and magnetic prospecting) were applied in a well-known geothermal area located inside Timanfaya National Park. The area with the highest ground temperatures was correlated with the location that exhibited strong ground penetrating radar reflections, high resistivity values and low magnetic anomalies. Moreover, the high ground temperature imaging results depicted a shallow, bowl-shaped body that narrowed and deepened vertically to a depth greater than 45 m. The ground penetrating radar survey was repeated three years later and exhibited subtle variations of the signal reflection patterns, or signatures, suggesting a certain temporal variation of the ground temperature. By identifying similar areas with the same geophysical signature, up to four additional geothermal areas were revealed. We conclude that the combined use of ground penetrating radar, electromagnetic induction and magnetic methods constitutes a valuable tool to locate and study both the geometry at depth and seasonal variability of geothermal areas associated with hot dry rock systems.
http://creativecommons.org/licenses/by-nc-sa/4.0/
openAccess
Timanfaya volcanic area
HDR geothermal systems
GPR
EMI
Magnetic anomalies
Seasonality
Imaging Thermal Anomalies in Hot Dry Rock Geothermal Systems from Near-Surface Geophysical Modelling
artículo