3D electrical resistivity of Gran Canaria island using magnetotelluric data

Ledo, Juanjo; García-Merino, Marta; Larnier, H.; Ślęzak, Katarzyna; Piña-Varas, Perla; Marcuello, Álex; Queralt, Pilar; Pérez, Nemesio M.; Schmincke, H.-U.; Sumita, Mari

doi:10.1016/j.geothermics.2020.101945

Cited by 12 publications

(10 citation statements)

References 48 publications

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“…Meanwhile, in the small study area, the MT method was measured with the distance between sites varying from 1 to 5 km. For example, the measurement of the 3D MT at the geothermal in Southwest Iceland, in Grand Canaria Island, and Ayrobera geothermal Northeast Ethiopia with the distances between stations of ±2 km, ±4 km, and ± 1.5 km, respectively [31,32,53]. As a result, the acquired MT site distribution in this study could provide geometrical details from the hydrothermal system of the Seulawah Agam volcano.…”

Section: Magnetotellurics Data Acquisitionmentioning

confidence: 75%

“…Magnetotelluric imaging has become a common method in investigating volcanoes worldwide [3,20,31]. The method works by utilizing the Earth's magnetic field with a frequency of 10 −4 -10 4 Hz.…”

Section: Discussionmentioning

confidence: 99%

“…The present pseudo-3D model is a combination of 2D model inversion of several profiles, although the analytical data of the tensor phase showing that on the layer characterized by 2D and 3D anomalies. Indeed, many studies suggest that the 2D inversion response could have explained the geothermal system very well [31,32,35], especially for volcanoes located in tropical regions on high topographies. However, for better results, a full 3D inversion should be applied [31,32,35].…”

Section: Discussionmentioning

confidence: 99%

“…In fact, a geothermal energy system is generally composed of a system of faults and fractures that generate geothermal fluid [3,20], with a high concentration of dissolved salts, resulting in a large presence of conductive electrolytes in the rock matrix. The conductivity of the fluid is highly temperature dependent, and geothermal systems are generally characterized by having higher conductivity than the host rock, making these systems ideal targets for electromagnetic (EM) measurement methods [31], especially magnetotellurics (MT)-based methods [32,33].…”

Section: Introductionmentioning

confidence: 99%

“…In fact, the geothermal industry has regularly applied EM methods for hydrothermal imaging systems, while previous studies [23,34] have effectively described the potential of the MT method for mapping the clay caps and reservoirs that are conductive and are commonly present in geothermal systems. Because of its relatively low cost and its high effectiveness for detecting low-resistive zones below the surface, the MT method has become the most frequently applied technique for geothermal exploration [3,31,35]. Figure 1 shows the location of the Seulawah Agam volcano, which lies 85 km from Banda Aceh City.…”

Section: Introductionmentioning

confidence: 99%

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Mapping of Fault and Hydrothermal System beneath the Seulawah Volcano Inferred from a Magnetotellurics Structure

et al. 2021

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Magnetotellurics (MT) is an important geophysical method for exploring geothermal systems, with the Earth resistivity obtained from the MT method proving to be useful for the hydrothermal imaging changes of the system. In this research, we applied the MT method to map the geothermal system of the Seulawah Agam volcano in northern Sumatra, a site intended for the construction of a geothermal power plant with an estimated energy of 230 Mwe. Herein, 3D MT measurements were carried out, covering the entire area of the volcano and the various intersecting local faults from the Seulimeum segment in the NW–SE direction. Based on Occam 2D inversion, a conductive anomaly (<10 ohm·m) near the surface was identified in response to specific manifestation areas, including the Heutsz crater on the northern side and the Cempaga crater on the southern side. A further conductive anomaly was also found at a depth of 1 km, which was presumably due to a clay cap layer covering the fluid in the reservoir layer below the surface, where the manifestation areas are formed at various locations (where faults and fractures are found) owing to the fluid in the reservoir rising to the surface. The MT modeling also revealed that the reservoir layer in Seulawah Agam lies at a depth of 2 km with a higher resistivity of 40–150 ohm·m, which is the main target of geothermal energy exploration. At the same time, the heat source zone where magma is located was estimated to lie in two locations, namely, on the northern side centering on the Heutsz crater area and the southern side in the Cempaga crater area. A clear 3D structure obtained via Occam inversion was also used to visualize the hydrothermal flow in the Seulawah Agam volcano that originates from two heat source zones, where one structure that was consistent across all models is the conductive zone that reaches a depth of 5 km in the south in response to the regional faulting of the Seulimeum segment. Based on the MT research, we concluded that the volcano has the geothermal potential to be tapped into power plant energy in the future.

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Section: Magnetotellurics Data Acquisitionmentioning

confidence: 75%

Section: Discussionmentioning

confidence: 99%