Hydrothermal eruptions at El Humazo, Domuyo geothermal field, Argentina: Insights into the eruptive dynamics and controls

D’Elía, Leandro; Páez, Gerardo Néstor; Hernando, Irene Raquel; Petrinovic, Iván Alejandro; López, Luciano; Kürten, Germán; Vigiani, Luis

doi:10.1016/j.jvolgeores.2020.106786

Cited by 8 publications

(13 citation statements)

References 54 publications

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“…Recent investigations demonstrate how characteristic lithologies and particle properties within steam-driven (phreatic and hydrothermal) eruption deposits, together with the characterization of local geology and alteration settings, can be used to infer the triggers, dynamics, and sources of such eruptions (Breard et al 2014 ; Mayer et al 2015 ; Montanaro et al 2016a , 2020 ; Pittari et al 2016 ; D’Elia et al 2020 ). Valuable insights into the properties of source rocks can also come from analysing drill cuttings and/or cores from nearby eruptive sites (Mastin 1991 ; Gallagher et al 2020 ).…”

Section: Introductionmentioning

confidence: 99%

Stratigraphic reconstruction of the Víti breccia at Krafla volcano (Iceland): insights into pre-eruptive conditions priming explosive eruptions in geothermal areas

Montanaro

Mortensen²,

Weisenberger

et al. 2021

Bull Volcanol

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Krafla central volcano in Iceland has experienced numerous basaltic fissure eruptions through its history, the most recent examples being the Mývatn (1724‒1729) and Krafla Fires (1975–1984). The Mývatn Fires opened with a steam-driven eruption that produced the Víti crater. A magmatic intrusion has been inferred as the trigger perturbing the geothermal field hosting Víti, but the cause(s) of the explosive response remain uncertain. Here, we present a detailed stratigraphic reconstruction of the breccia erupted from Víti crater, characterize the lithologies involved in the explosions, reconstruct the pre-eruptive setting, fingerprint the eruption trigger and source depth, and reveal the eruption mechanisms. Our results suggest that the Víti eruption can be classified as a magmatic-hydrothermal type and that it was a complex event with three eruption phases. The injection of rhyolite below a pre-existing convecting hydrothermal system likely triggered the Víti eruption. Heating and pressurization of shallow geothermal fluid initiated disruption of a scoria cone “cap” via an initial series of small explosions involving a pre-existing altered weak zone, with ejection of fragments from at least 60-m depth. This event was superseded by larger, broader, and dominantly shallow explosions (~ 200 m depth) driven by decompression of hydrothermal fluids within highly porous, poorly compacted tuffaceous hyaloclastite. This second phase was triggered when pressurized fluids broke through the scoria cone complex “cap”. At the same time, deep-rooted explosions (~ 1-km depth) began to feed the eruption with large inputs of fragmented rhyolitic juvenile and host rock from a deeper zone. Shallow explosions enlarging the crater dominated the final phase. Our results indicate that at Krafla, as in similar geological contexts, shallow and thin hyaloclastite sequences hosting hot geothermal fluids and capped by low-permeability lithologies (e.g. altered scoria cone complex and/or massive, thick lava flow sequence) are susceptible to explosive failure in the case of shallow magmatic intrusion(s).

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Section: Introductionmentioning

confidence: 99%

Stratigraphic reconstruction of the Víti breccia at Krafla volcano (Iceland): insights into pre-eruptive conditions priming explosive eruptions in geothermal areas

Montanaro

Mortensen²,

Weisenberger

et al. 2021

Bull Volcanol

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“…Here, we compare the Champagne Pool eruption to studies of natural explosion craters (Yokoo et al 2002;Graettinger and Valentine 2017;D'Elia et al 2020), and field-based explosion experiments (Goto et al 2001;Ohba et al 2002;Taddeucci et al 2013;Graettinger et al 2014;Sonder et al 2015;Macorps et al 2016). The experiments show that eruption dynamics and Fig.…”

Section: Eruption Dynamics and Energetic Considerationsmentioning

confidence: 97%

“…4a-f), and the large deposit thickness to the north, point to multiple shallow explosions at later stages of the eruption Table 2 Comparison of petrophysical properties, and median-fine grain size and componentry of naturally/experimentally fragmented material from drill cores vs. breccia blocks and matrix Drill cores that migrated/excavated northward Kennedy et al 2020;Montanaro et al 2020). Geothermal features such as hot-spring conduits, hydrothermal eruption vents, and collapsed craters, are most commonly found close to faults (Curewitz and Karson 1997;Rowland and Simmons 2012;D'Elia et al 2020). Structural features can also control vent migration during explosive events involving fluids rising through fractures (Ort and Carrasco-Núñez 2009).…”

Section: Eruption Trigger and Mechanismmentioning

confidence: 99%

“…The wide diversity of rock types in geothermal areas causes a great variability in hydrothermal eruption dynamics (Browne and Lawless 2001;Montanaro et al , 2020. By examining the characteristic lithologies and particle properties within hydrothermal eruption deposits, the dynamics and sources of eruptions can be estimated (Breard et al 2014;Mayer et al 2015;Montanaro et al , 2020Pittari et al 2016;D'Elia et al 2020). Valuable insights into the source rock properties come from analysing blocks within the hydrothermal breccias Heap et al 2017), or from rare shallow (<400 m) nearby drill cores.…”

Section: Introductionmentioning

confidence: 99%

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Hydrothermal eruption dynamics reflecting vertical variations in host rock geology and geothermal alteration, Champagne Pool, Wai-o-tapu, New Zealand

et al. 2020

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Hydrothermal eruptions are characterised by violent explosions ejecting steam, water, mud, and rock. They pose a risk to tourism and the operation of power plants in geothermal areas around the world. Large events with a severe destructive threat are often intensified by the injection of magmatic fluids along faults and fractures within volcano-tectonic rifting environments, such as the Taupo Volcanic Zone. How these hydrothermal eruptions progress, how craters form and the scale of ejecta impacts, are all influenced by the local geology and reservoir hydrology. By analysing breccia lithology, undisturbed strata proximal to the explosion sites, and conducting tailored decompression experiments, we elucidate the eruption sequence that formed Champagne Pool, Wai-o-tapu, New Zealand. This iconic touristic site was formed by a violent hydrothermal eruption at ~ 700 years B.P. Samples from undisturbed drill cores and blocks ejected in the eruption were fragmented in shock-tube experiments under the moderate pressure/temperature conditions estimated for this system (3–4 MPa, 210–220 °C). Our results show that this was a two-phase eruption. It started with an initial narrow jetting of deep-sourced lithologies, ejecting fragments from at least a 110-m depth. This event was overtaken by a larger, broader, and dominantly shallower eruption driven by decompression of much more geothermal fluid within a soft and porous ignimbrite horizon. The second phase was triggered once the initial, deeper-sourced eruption broke through a strong silicified aquitard cap. The soft ignimbrite collapsed during the second-phase eruption into the crater, to repeatedly choke the explosions causing short-term pressure rises that triggered ongoing deeper-sourced eruptions. The eruption spread laterally also by exploiting a local fault. These results are relevant for hydrothermal eruption hazard scenarios in environments where strong vertical variations in rock strength and porosity occur.

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“…Recent field (D'Elia et al, 2020;Kilgour et al, 2019;Mayer et al, 2017) and experimental studies (Haug et al, 2013;Mayer et al, 2015;Montanaro et al, 2016aMontanaro et al, , 2016b show how the explosion dynamics, magnitude and likelihood of steam-driven eruptions depend on the porosity and permeability of host rocks. Rock type can also influence the behavior of cracks and their ability to form and heal during advection of hydrothermal fluids (Kennedy et al, 2020).…”

Section: Citationmentioning

confidence: 99%

Host Rock Variability Powers the Diversity of Steam‐Driven Eruptions

Montanaro

Cronin

Scheu

et al. 2021

Geophysical Research Letters

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Steam-driven, phreatic and hydrothermal eruptions are a common explosive phenomenon in volcanic and geothermal systems (Browne & Lawless, 2001; Stix & Moor, 2018). In active volcanic terrains, phreatic eruptions may be triggered by the sudden arrival of extra fluid (gas, waters or brines) interacting with heat from intruding magma (Browne & Lawless, 2001; Stix & Moor, 2018). In geothermal settings, hydrothermal eruptions may be triggered by depressurization and steam-flashing of trapped hot pressurized fluids, released by earthquakes, landslides, or other localized natural hydrological disturbances (Browne & Lawless, 2001; Mastin, 1995; Thiéry & Mercury, 2009). Moreover, in both active volcanic and geothermal settings, hydrothermal alteration and mineral sealing can promote high local overpressures and thus more readily an explosive destabilization (Mayer et al, 2015, 2016; Scolamacchia & Cronin, 2016). Irrespective of the presence of shallow magma, flashed water contains enough energy to efficiently fragment rock and violently eject material upwards and laterally (Montanaro et al., 2016a; Morgan et al., 2009). Often impulsive and shortlived relative to magmatic eruptions, they are still deadly due to their sudden onsets, and the generation of violent blasts (

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Hydrothermal eruptions at El Humazo, Domuyo geothermal field, Argentina: Insights into the eruptive dynamics and controls

Cited by 8 publications

References 54 publications

Stratigraphic reconstruction of the Víti breccia at Krafla volcano (Iceland): insights into pre-eruptive conditions priming explosive eruptions in geothermal areas

Stratigraphic reconstruction of the Víti breccia at Krafla volcano (Iceland): insights into pre-eruptive conditions priming explosive eruptions in geothermal areas

Hydrothermal eruption dynamics reflecting vertical variations in host rock geology and geothermal alteration, Champagne Pool, Wai-o-tapu, New Zealand

Host Rock Variability Powers the Diversity of Steam‐Driven Eruptions

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