On the detectability of Teide volcano magma chambers (Tenerife, Canary Islands) with magnetotelluric data

Piña-Varas, Perla; Ledo, Juanjo; Queralt, Pilar; Marcuello, Álex; Pérez, Nemesio M.

doi:10.1186/s40623-018-0783-y

Cited by 31 publications

(19 citation statements)

References 41 publications

(65 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Such a result can be supported by recent temperature measurements carried out in the south of the island 16 , with values of 90–130 °C indicative of the presence of a clay cap at the top of an active geothermal system 38 . Furthermore, similar features have been recently evidenced in the nearby Tenerife island 24 , and interpreted as the clay cap overlaying the magmatic reservoir 39 .…”

Section: Discussionsupporting

confidence: 76%

La Palma island (Spain) geothermal system revealed by 3D magnetotelluric data inversion

Paolo

Ledo

Ślęzak

et al. 2020

Sci Rep

Self Cite

View full text Add to dashboard Cite

The study of geothermal systems is nowadays a topic of great importance because of the huge amount of energy that could be converted in electricity for human consumption from such sources. Among the various geophysical methods employed to study geothermal reservoirs, the magnetotelluric (MT) method is capable to reveal the internal structures of the subsurface and interpret the geological structures from the electrical resistivity. We present the first 3D resistivity model of La Palma (Canary archipelago, Spain) obtained from a dataset of 44 broadband magnetotelluric soundings distributed around the island. Our results highlight the presence of resistivity anomalies, spatially coinciding with density anomalies present in literature. In the north of the island, a high resistivity anomaly can be interpreted as the signature of an old intrusive body beneath the Taburiente caldera. In the south, a complex resistivity structure around the Cumbre Vieja volcanic ridge could be indicative of presence of an active geothermal system. In particular, low-resistivity anomalies, located in a high-fractured zone, have values compatible with clay alteration caps (illite and illite–smectite). Such a result suggests the presence of hot rocks, or a dike system, heating fluids in the interior of Cumbre Vieja volcanic system.

show abstract

Section: Discussionsupporting

confidence: 76%

La Palma island (Spain) geothermal system revealed by 3D magnetotelluric data inversion

Paolo

Ledo

Ślęzak

et al. 2020

Sci Rep

Self Cite

View full text Add to dashboard Cite

show abstract

“…Electrical resistivity values range from 2.5 to 2,200 Ω•m, and thus agree with the previous 1-D resistivity model obtained at Miyakejima by Zlotnicki et al (2003) from audio-magnetotellurics soundings. This resistivity range is also consistent with several volcanic islands (e.g., Gailler et al, 2018;Piña-Varas et al, 2018;Pryet et al, 2012;Revil et al, 2011) and continental arc volcanoes (e.g., Aizawa et al, 2005;Heise et al, 2016).…”

Section: Description Of the Main Unitssupporting

confidence: 85%

Hydrothermal and Magmatic System of a Volcanic Island Inferred From Magnetotellurics, Seismicity, Self‐potential, and Thermal Image: An Example of Miyakejima (Japan)

et al. 2021

View full text Add to dashboard Cite

Active hydrothermal systems develop during repose periods of volcanoes within the first kilometers of their edifices when ascending hot magmatic fluids (liquid or gas) encounter meteoric water recharge and/or seawater. Free convection and forced circulation occur, leading to surface manifestations such as fumaroles and hot springs.Intensive volcanic hazards are associated with pervasive hydrothermal systems. Phreatic and phreatomagmatic eruptions represent the most common hazards occurring when hot magmatic fluids or magma are injected into a pre-existing hydrothermal system (Heiken & Wohletz, 1987;Stix, 2018). Pore-water is flashed creating an overpressure until the potential rupture of host-rock, leading to a sudden explosive eruption (e.g., Mannen et al., 2019;Yamaoka et al., 2016). Other hydrothermal-related hazards exist without necessarily involving magmatic origin. Indeed, long-term host-rock interactions between heat, water, and magmatic fluids lead to numerous modifications of the physical-chemical properties of host rocks and fluids. Percolation of hot and acidic fluids (<400°C) dissolves host-rock primary minerals and precipitates low-permeability clay minerals (Pirajno, 2008). Such alteration products create a barrier to the flow of fluids (called Abstract Phreatic and phreatomagmatic eruptions represent some of the greatest hazards occurring on volcanoes. They result from complex interactions at a depth between rock, water, and magmatic fluids. Understanding and assessing such processes remain a challenging task, notably because a large-scale characterization of volcanic edifices is often lacking. Here we focused on Miyakejima Island, an inhabited 8-km-wide stratovolcano with regular phreatomagmatic activity. We imaged its plumbing system through a combination of four geophysical techniques: magnetotellurics, seismicity, self-potential, and thermal image. We thus propose the first comprehensive interpretation of the volcanic island in terms of rock properties, temperature, fluid content, and fluid flow. We identify a shallow aquifer lying above a clay cap (<1 km depth) and reveal its relation with magmatic-tectonic features and past eruptive activity. At greater depths (2-4.5 km), we infer a seismogenic resistive region interpreted as a magmatic gas-rich reservoir (≥370°C). From this reservoir, gases rise through a fractured conduit before being released in the fumarolic area at ∼180°C. During their ascent, these hot fluids cross a ∼1.2-km-long liquid-dominated zone causing local steam explosions. Such magmatic-hydrothermal interaction elucidates (i) the origin of the long-period seismic events and (ii) the mixing mechanism between magmatic and hydrothermal fluids, which was previously observed in the geochemical signature of fumaroles. Our results demonstrate that combining multidisciplinary large-scale methods is a relevant approach to better understand volcanic systems, with implications for monitoring strategies. GRESSE ET AL.

show abstract

“…In this paper, the distribution of the clay cap around the Yugama crater was imaged in detail, and it was found to be nearly bell shaped. These capping structures, the hydrothermal alteration products, are commonly found in geothermal areas (e.g., Heise et al 2008;Yamaya et al 2013;Seki et al 2015;Piña-Varas et al 2018;Yoshimura et al 2018;Kanda et al 2019). The bottom of the C1 smectite clay conductor is interpreted as the isotherm of 200 °C.…”

Section: Clay-cap Conductor (C1) and Inner Resistor (R1)mentioning

confidence: 99%

Anatomy of active volcanic edifice at the Kusatsu–Shirane volcano, Japan, by magnetotellurics: hydrothermal implications for volcanic unrests

Tseng

Ogawa

Nurhasan

et al. 2020

Earth Planets Space

View full text Add to dashboard Cite

We aimed to perform three-dimensional imaging of the underlying geothermal system to a depth of 2 km using magnetotellurics (MT) at around the Yugama crater, the Kusatsu–Shirane Volcano, Japan, which is known to have frequent phreatic eruptions. We deployed 91 MT sites focusing around the peak area of 2 km × 2 km with typical spacings of 200 m. The full tensor impedances and the magnetic transfer functions were inverted, using an unstructured tetrahedral finite element code to include the topographic effect. The final model showed (1) low-permeability bell-shaped clay cap (C1) as the near-surface conductor, (2) brine reservoir as a deep conductor (C3) at a depth of 1.5 km from the surface, and (3) a vertical conductor (C2) connecting the deep conductor to the clay cap which implies an established fluid path. The columnar high-seismicity distribution to the east of the C2 conductor implies that the flushed vapor and magmatic gas was released from the brine reservoir by breaking the silica cap at the brittle–ductile transition. The past magnetization/demagnetization sources and the inflation source of the 2014 unrest are located just below the clay cap, consistent with the clay capped geothermal model underlain by brine reservoir. The resistivity model showed the architecture of the magmatic–hydrothermal system, which can explain the episodic volcanic unrest.

show abstract

On the detectability of Teide volcano magma chambers (Tenerife, Canary Islands) with magnetotelluric data

Cited by 31 publications

References 41 publications

La Palma island (Spain) geothermal system revealed by 3D magnetotelluric data inversion

La Palma island (Spain) geothermal system revealed by 3D magnetotelluric data inversion

Hydrothermal and Magmatic System of a Volcanic Island Inferred From Magnetotellurics, Seismicity, Self‐potential, and Thermal Image: An Example of Miyakejima (Japan)

Anatomy of active volcanic edifice at the Kusatsu–Shirane volcano, Japan, by magnetotellurics: hydrothermal implications for volcanic unrests

Contact Info

Product

Resources

About