Summit Acid Crater Lakes and Flank Instability in Composite Volcanoes

Delmelle, Pierre; Henley, Richard W.; Opfergelt, Sophie; Detienne, Marie

doi:10.1007/978-3-642-36833-2_12

Cited by 20 publications

(19 citation statements)

References 66 publications

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“…The removal of the lake appears to have destabilized the surrounding crater walls and lake edge. These observations indicate that crater lakes play a critical role in the stability of the edifice and that their removal, in addition to longer‐term chemical weakening of the edifice rocks (Delmelle et al, ; Reid, ), can lead to the reactivation of landslides and potential slope failures which has important implications for volcanic hazard monitoring not previously considered at White Island.…”

Section: Discussionmentioning

confidence: 99%

Crater Lake Controls on Volcano Stability: Insights From White Island, New Zealand

Hamling

2017

Geophysical Research Letters

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Many volcanoes around the world host summit crater lakes but their influence on the overall stability of the edifice remains poorly understood. Here I use satellite radar data acquired by TerraSAR‐X from early 2015 to July 2017 over White Island, New Zealand, to investigate the interaction of the crater lake and deformation of the surrounding edifice. An eruption in April 2016 was preceded by a period of uplift within the crater floor and drop in the lake level. Modeling of the uplift indicates a shallow source located at ∼100 m depth in the vicinity of the crater lake, likely coinciding with the shallow hydrothermal system. In addition to the drop in the lake level, stress changes induced by the inflation suggest that the pressurization of the shallow hydrothermal system helped promote failure along the edge of the crater lake which collapsed during the eruption. After the eruption, and almost complete removal of the crater lake, large areas of the crater wall and lake edge began moving downslope at rates approaching 400 mm/yr. The coincidence between the rapid increase in the displacement rates and removal of the crater lake suggests that the lake provides a physical control on the stability of the surrounding edifice.

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Section: Discussionmentioning

confidence: 99%

Crater Lake Controls on Volcano Stability: Insights From White Island, New Zealand

Hamling

2017

Geophysical Research Letters

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“…Low pressures favor high SO 2 /H 2 S and HCl/NaCl in the emitted magmatic vapors, increasing the acidity of any near-surface condensate (Symonds et al, 1994;Shinohara, 2009). The creation of acid is further favored where crater lakes are present at the surface, as the supply of capping groundwater water minimizes the possibility that the gas-steam mixture can escape directly to the atmosphere (Delmelle et al, 2015). Such environments are highly analogous and indeed inseparable from the high-sulfidation environments responsible for some types of epithermal ore formation (Henley and McNabb, 1978;Hedenquist et al, 1998;Berger et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

“…Such environments are highly analogous and indeed inseparable from the high-sulfidation environments responsible for some types of epithermal ore formation (Henley and McNabb, 1978;Hedenquist et al, 1998;Berger et al, 2014). In the most acid-altered areas, the dominant material is various forms of silica (Hemley and Jones, 1964;Henley and McNabb, 1978;Delmelle et al, 2015), which may convert with time from amorphous silica (opal-A) to more crystalline forms of silica, including opal-CT, opal-C, chalcedony and quartz (Rodgers et al, 2004). Other minerals may include alunite, anatase, and kaolinite.…”

Section: Introductionmentioning

confidence: 99%

Opal-A in Glassy Pumice, Acid Alteration, and the 1817 Phreatomagmatic Eruption at Kawah Ijen (Java), Indonesia

et al. 2018

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At Kawah Ijen (Indonesia), vigorous SO 2 and HCl degassing sustains a hyperacid lake (pH ∼0) and intensely alters the subsurface, producing widespread residual silica and advanced argillic alteration products. In 1817, a VEI 2 phreatomagmatic eruption evacuated the lake, depositing a widespread layer of muddy ash fall, and sending lahars down river drainages. We discovered multiple types of opaline silica in juvenile low-silica dacite pumice and in particles within co-erupted laharic sediments. Most spectacular are opal-replaced phenocrysts of plagioclase and pyroxene adjacent to pristine matrix glass and melt inclusions. Opal-bearing pumice has been found at numerous sites, including where post-eruption infiltration of acid water is unlikely. Through detailed analyses of an initial sampling of 1817 eruption products, we find evidence for multiple origins of opaline materials in pumice and laharic sediments. Evidently, magma encountered acid-altered materials in the subsurface and triggered phreatomagmatic eruptions. Syn-eruptive incorporation of opal-alunite clasts, layered opal, and fragment-filled vesicles of opal and glass, all suggest magma-rock interactions in concert with vesiculation, followed by cooling within minutes. Our experiments at magmatic temperature confirm that the opaline materials would show noticeable degradation in time periods longer than a few tens of minutes. Some glassy laharic sedimentary grains are more andesitic than the main pumice type and may represent older volcanic materials that were altered beneath the lake bottom and were forcefully ejected during the 1817 eruption. A post-eruptive origin remains likely for most of the opal-replaced phenocrysts in pumice. Experiments at 25 • C and 100 • C reveal that when fresh pumice is bathed in Kawah Ijen hyperacid fluid for 6 weeks, plagioclase is replaced without altering either matrix glass or melt inclusions. Moreover, lack of evidence for high-temperature annealing of the opal suggests that post-eruption alteration of pumice is more likely than pre-eruption envelopment of Lowenstern et al. Opal in Glassy Pumice euhedral opal-replaced phenocrysts in dacitic melt. At Ijen and elsewhere, the ascent of magma into hydrous acid-altered mineral assemblages (e.g., opal, kaolinite, alunite) could induce rapid dehydration of hydrous minerals and amorphous materials, generating considerable steam and contributing to magmatic-hydrothermal and phreatomagmatic explosions.

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“…According to Ramírez et al (2013), the lake had a variable temperature (16-35°C), pH (3.0-5.85) and color over time (red, green, turquoise, mustard). The permeability due to fractures in the "Crater Activo" probably contributed significantly to the volume changes (draining) of the volcanic lake, and the lake-hydrothermal system is probably hydrogeologically connected to the Río Sucio springs, NW of the volcano (Ramírez et al, 2013;Pierre et al, 2015). Intra-crater fumaroles were reported several times for the period 1998-2001 on the Crater Activo (Ramírez et al, 2013).…”

Section: Study Sitesmentioning

confidence: 99%

Extremely high diversity of sulfate minerals in caves of the Irazú Volcano (Costa Rica) related to crater lake and fumarolic activity

Ulloa¹,

Gázquez²,

Sanz-Arranz³

et al. 2018

IJS

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Abstract:The caves of the Irazú volcano (Costa Rica), became accessible after the partial collapse of the NW sector of the Irazú volcano in 1994, offering the opportunity to investigate active minerogenetic processes in volcanic cave environments. We performed a detailed mineralogical and geochemical study of speleothems in the caves Cueva los Minerales and Cueva Los Mucolitos, both located in the northwest foothills of the main crater. Mineralogical analyses included X-ray diffraction (XRD) and Raman spectroscopy, while geochemical characterization used Energy Dispersive X-ray spectroscopy (EDX) coupled to Scanning Electron Microscopy (SEM). In addition, measurements of environmental parameters in the caves, cave drip water and compilation of geochemical analyses of the Irazú volcanic lake (~150 m above the cave level) and fumarole analyses were conducted between 1991 and 2014. We identified forty-eight different mineral phases, mostly rare hydrated sulfates of the alunite, halotrichite, copiapite, kieserite and rozenite groups, thirteen of which are described here as cave minerals for the first time. This includes the first occurrence in cave environments of aplowite, bieberite, boyleite, dietrichite, ferricopiapite, ferrinatrite, lausenite, lishizhenite, magnesiocopiapite, marinellite, pentahydrite, szomolnokite, and wupatkiite. The presence of other new cave minerals such as tolbachite, mercallite, rhomboclase, cyanochroite, and retgersite, is likely but could not be confirmed by various mineralogical techniques. Uplifting of sulfurous gases, water seepage from the Irazú volcanic lake and hydrothermal interactions with the volcanic host rock are responsible for such extreme mineralogical diversity. These findings make the caves of the Irazú volcano a world-type-reference locality for investigations on the formation and assemblage of sulfate minerals and the biogeochemical cycle of sulfur, with potential implications for Astrobiology and Planetary science.hydrated sulfates, sulfate speleothems, volcanic caves, crater lake, cave minerogenesis Ulloa A., Gázquez F., Sanz-Arranz A., Medina J., Rull F., Calaforra J.M., Alvarado G.E., Martínez M., Avard G., de Moor J.M. and De Waele J., 2018. Extremely high diversity of sulfate minerals in caves of the Irazú Volcano (Costa Rica) related to crater lake and fumarolic activity.

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Summit Acid Crater Lakes and Flank Instability in Composite Volcanoes

Cited by 20 publications

References 66 publications

Crater Lake Controls on Volcano Stability: Insights From White Island, New Zealand

Crater Lake Controls on Volcano Stability: Insights From White Island, New Zealand

Opal-A in Glassy Pumice, Acid Alteration, and the 1817 Phreatomagmatic Eruption at Kawah Ijen (Java), Indonesia

Extremely high diversity of sulfate minerals in caves of the Irazú Volcano (Costa Rica) related to crater lake and fumarolic activity

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