Special issue “The phreatic eruption of Mt. Ontake volcano in 2014”

Yamaoka, K.; Geshi, Nobuo; Hashimoto, Tatsuichiro; Ingebritsen, Steven E.; Oikawa, Teruki

doi:10.1186/s40623-016-0548-4

Cited by 41 publications

(40 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Immediately after the eruption, SO 2 emission rates of >2,000 t/d were measured, and rapidly decreased thereafter, though hydrothermal H 2 S emissions continued (Mori et al, 2016). It appears likely that the eruption was at least partially triggered by input of magmatic gas at the base of the acidaltered hydrothermal system (Sano et al, 2015;Mori et al, 2016;Yamaoka et al, 2016).…”

Section: Speculations On the Connection Between Phreatomagmatic Activmentioning

confidence: 99%

See 1 more Smart Citation

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

et al. 2018

View full text Add to dashboard Cite

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.

show abstract

Section: Speculations On the Connection Between Phreatomagmatic Activmentioning

confidence: 99%

“…Ontake (Japan) in 2014 (Yamaoka et al, 2016). Dry and wet explosions resulted in widespread generation of ballistic debris, pyroclastic density currents and a lahar whose mudrich waters were disgorged from within the volcano.…”

Section: Speculations On the Connection Between Phreatomagmatic Activmentioning

confidence: 99%

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

et al. 2018

View full text Add to dashboard Cite

show abstract

“…A phreatic eruption is an eruption without any eruption of juvenile magma. However, recent studies imply that subsurface injection of magma or magmatic fluid can trigger volcanic unrest and subsequent phreatic eruptions (e.g., Yamaoka et al 2016). In this special issue, two contributions modeled the sequence from an event of magma or magmatic fluid injection at depth to a phreatic eruption through various precursory phenomena.…”

Section: Modeling Of Phreatic Eruptionsmentioning

confidence: 99%

“…Kusatsu-Shirane ) is still ongoing, a special issue for the 2014 eruption of Mt. Ontake was organized in this journal, and compiled observations and models of preparatory process of this unexpected eruption, which resulted largest number of victims after World War II (Yamaoka et al 2016).…”

Section: Introductionmentioning

confidence: 99%

Special issue “Towards forecasting phreatic eruptions: examples from Hakone volcano and some global equivalents”

Mannen

Roman

Leonard

et al. 2019

Earth Planets Space

View full text Add to dashboard Cite

show abstract

“…Recently, more than 50 people were killed by the 2014 Mt. Ontake eruption and most of the fatalities were caused by ballistic projectiles (Oikawa et al 2016;Tsunematsu et al 2016;Yamaoka et al 2016). Another fatality occurred at Mt.…”

Section: Introductionmentioning

confidence: 99%

Transport of ballistic projectiles during the 2015 Aso Strombolian eruptions

Tsunematsu

Ishii

Yokoo

2019

Earth Planets Space

View full text Add to dashboard Cite

Large pyroclasts-often called ballistic projectiles-cause many casualties and serious damage on people and infrastructures. One useful measure of avoiding such disasters is to numerically simulate the ballistic trajectories and forecast where large pyroclasts deposit. Numerical models are based on the transport dynamics of these particles. Therefore, in order to accurately forecast the spatial distribution of these particles, large pyroclasts from the 2015 Aso Strombolian eruptions were observed with a video camera. In order to extrapolate the mechanism of particle transport, we have analyzed the frame-by-frame images and obtained particle trajectories. Using the trajectory data, we investigated the features of Strombolian activity such as ejection velocity, explosion energy, and particle release depth. As gas flow around airborne particles can be one of the strongest controlling factors of particle transport, the gas flow velocities were estimated by comparing the simulated and observed trajectories. The range of the ejection velocity of the observed eruptions was 5.1-35.5 m/s, while the gas flow velocity, which is larger than the ejection velocity, reached a maximum of 90 m/s, with mean values of 25-52 m/s for each bursting event. The particle release depth, where pyroclasts start to move separately from the chunk of magmatic fragments, was estimated to be 11-13 m using linear extrapolation of the trajectories. Although these parabolic trajectories provide us with an illusion of particles unaffected by the gas flow, the parameter values show that the particles are transported by the gas flow, which is possibly released from inside the conduit.

show abstract

Special issue “The phreatic eruption of Mt. Ontake volcano in 2014”

Cited by 41 publications

References 22 publications

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

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

Special issue “Towards forecasting phreatic eruptions: examples from Hakone volcano and some global equivalents”

Transport of ballistic projectiles during the 2015 Aso Strombolian eruptions

Contact Info

Product

Resources

About