Experimental craters formed by single and multiple buried explosions and implications for volcanic craters with emphasis on maars

Valentine, Greg A.; White, James D. L.; Ross, Pierre-Simon; Amin, Jamal; Taddeucci, Jacopo; Sonder, Ingo; Johnson, Peter J.

doi:10.1029/2012gl053716

Cited by 54 publications

(47 citation statements)

References 12 publications

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“…For instance, Valentine and White [29] propose an alternative model that allows multiple levels of country rock disruption and fragmentation, based on effective mixing by debris jets, an important subsurface transport phenomenon in phreatomagmatic vent complexes that is defined as an upward-moving stream of volcaniclastic debris, magmatic gases, and water vapor ± liquid water droplets, occurring on multiple vertical levels within a growing subsurface diatreme (e.g., [144]). This conceptual model is in accordance with the observed irregular distribution of accidental lithics in ejecta rings (e.g., [145]), field examples on diatreme geometry (e.g., [79]), but also on experimental cratering studies (e.g., [109,124,146]) and geophysical modeling (e.g., [80,81,147]). Chako Tchamabé et al [11] also suggested that the variation of juvenile populations within the stratigraphic sequence of maars might reflect a potential mode of explosions during maar-diatreme formation (Figure 7).…”

Section: Growth Of Complex Monogenetic Volcanoessupporting

confidence: 54%

How Polygenetic are Monogenetic Volcanoes: Case Studies of Some Complex Maar‐Diatreme Volcanoes

Tchamabé¹,

Keresztúri²,

Németh³

et al. 2016

Updates in Volcanology - From Volcano Modelling to Volcano Geology

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The increasing number of field investigations and various controlled benchtop and largescale experiments have permitted the evaluation of a large number of processes involved in the formation of maar-diatreme volcanoes, the second most common type of smallvolume subaerial volcanoes on Earth. A maar-diatreme volcano is recognized by a volcanic crater that is cut into country rocks and surrounded by a low-height ejecta rim composed of pyroclastic deposits of few meters to up to 200 m thick above the syn-eruptive surface level. The craters vary from 0.1 km to up to 5 km wide and vary in depth from a few dozen meters to up to 300 m deep. Their irregular morphology reflects the simple or complex volcanic and cratering processes involved in their formation. The simplicity or complexity of the crater or the entire maar itself is usually observed in the stratigraphy of the surrounding ejecta rings. The latter are composed of sequences of successive alternating and contrastingly bedded phreatomagmatic-derived dilute pyroclastic density currents (PDC) and fallout depositions, with occasional interbedded Strombolian-derived spatter materials or scoria fall units, exemplifying the changes in the eruptive styles during the formation of the volcano. The entire stratigraphic sequence might be preserved as a single eruptive package (small or very thick) in which there is no stratigraphic gap or significant discordance indicative of a potential break during the eruption. A maar with a single eruptive deposit is quantified as monogenetic maar, meaning that it was formed by a single eruptive vent from which only a small and ephemeral magma erupted over a short period of time. The stratigraphy may also display several packages of deposits separated either by contrasting discordance surfaces or paleosoils, which reflect multiple phases or episodes of eruptions within the same maar. Such maars are characterized as complex polycyclic maars if the length of time between the eruptive events is relatively short (days to years). For greater length of time (thousands to millions of years), the complex maar will be quantified as polygenetic. These common depositional breaks interpreted as signs of temporal interruption of the eruptions for various timescales also indicate deep magma system processes; hence magmas of different types might erupt during the formation of both simple and complex maars. The feeding dikes can interact with groundwater and form closely distributed small craters. The latter can coalesce to form a final crater with various shapes depending on the distance between them. This observation indicates the significant role of the magmatic plumbing system on the formation and growth of complex and polygenetic maar-diatreme volcanoes.

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Section: Growth Of Complex Monogenetic Volcanoessupporting

confidence: 54%

How Polygenetic are Monogenetic Volcanoes: Case Studies of Some Complex Maar‐Diatreme Volcanoes

Tchamabé¹,

Keresztúri²,

Németh³

et al. 2016

Updates in Volcanology - From Volcano Modelling to Volcano Geology

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“…However, to our knowledge, only Valentine et al . [] performed field‐scale explosion experiments that involved multiple explosions occurring within the same crater. The crater shapes and sizes were documented after each explosion [ Valentine et al ., ], while the sub‐crater deposits (partly analogous to natural diatremes) are investigated by Ross et al .…”

Section: Introductionmentioning

confidence: 99%

The effect of pre‐existing craters on the initial development of explosive volcanic eruptions: An experimental investigation

Taddeucci

Valentine

Sonder

et al. 2013

Geophysical Research Letters

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[1] Most volcanic eruptions occur in craters formed by previous activity. The presence of a crater implies specific confinement geometries, variably filled by loose fragmental deposits, which are expected to exert a strong, yet poorly studied, control on the violent gas expansion that drives the eruption. Here we analyze patterns of ejection from buried explosions in analog experiments, in order to investigate how the presence of a crater and changes in explosion depth and intensity may affect the formation of eruptive ejecta jets. Results show that scaled depth (charge burial depth divided by the cubic root of charge energy) controls the velocity and, partly, spread angle of eruptive jets independently of the presence of a pre-existing crater. Conversely, for a fixed scaled depth, the presence of a preexisting crater limits the development of a laterally expanding annulus of the jet. These results are directly applicable to interpretation of volcanic explosions.

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“…Nevertheless, there are alternative processes, such as volcanic eruptions and explosions, that can also produce craters [5][6][7][8][9][10][11][12]. For instance, a maar is a natural depression created by an underground steam explosion that occurs when magma comes into contact with shallow groundwater [7].…”

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confidence: 99%

Craters and Granular Jets Generated by Underground Cavity Collapse

2015

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We study experimentally the cratering process due to the explosion and collapse of a pressurized air cavity inside a sand bed. The process starts when the cavity breaks and the liberated air then rises through the overlying granular layer and produces a violent eruption; it depressurizes the cavity and, as the gas is released, the sand sinks under gravity, generating a crater. We find that the crater dimensions are totally determined by the cavity volume; the pressure does not affect the morphology because the air is expelled vertically during the eruption. In contrast with impact craters, the rim is flat and, regardless of the cavity shape, it evolves into a circle as the cavity depth increases or if the chamber is located deep enough inside the bed, which could explain why most of the subsidence craters observed in nature are circular. Moreover, for shallow spherical cavities, a collimated jet emerges from the collision of sand avalanches that converge concentrically at the bottom of the depression, revealing that collapse under gravity is the main mechanism driving the jet formation.

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Experimental craters formed by single and multiple buried explosions and implications for volcanic craters with emphasis on maars

Cited by 54 publications

References 12 publications

How Polygenetic are Monogenetic Volcanoes: Case Studies of Some Complex Maar‐Diatreme Volcanoes

How Polygenetic are Monogenetic Volcanoes: Case Studies of Some Complex Maar‐Diatreme Volcanoes

The effect of pre‐existing craters on the initial development of explosive volcanic eruptions: An experimental investigation

Craters and Granular Jets Generated by Underground Cavity Collapse

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