Ballistic ejecta from the 1988–1989 andesitic Vulcanian eruptions of Tokachidake volcano, Japan: morphological features and genesis

Yamagishi, Hisakazu; Feebrey, Craig A.

doi:10.1016/0377-0273(94)90082-5

Cited by 20 publications

(16 citation statements)

References 8 publications

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“…The bombs, up to 60 cm in diameter, have a breadcrusted surface, are mainly subrounded, and display a radial/jigsawjointed fracture pattern with chilled margins and are set in a sandy matrix supporting centimetre-sized glassy and older lava fragments. The bombs are well preserved and show fracturing, indicating that they were still hot ballistic ejecta when the lahar was emplaced (Yamagishi & Feebrey 1994). No charcoal or degassing pipes have been found, however, indicating the bulk of the deposit may have been cold on deposition.…”

mentioning

confidence: 81%

Quaternary lahar stratigraphy of the western Ruapehu ring plain, New Zealand

Lecointre

Neall

Palmer

1998

New Zealand Journal of Geology and Geophysics

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One of the most widespread hazards associated with explosive activity at Mt Ruapehu is the production of potentially destructive lahars. Volcanic activity at this andesite stratovolcano has produced numerous lahars throughout Quaternary time, with the resulting deposits being preserved principally on the lower slopes of the composite cone and its ring plain. This paper describes the stratigraphy of volcaniclastic sequences on the western Ruapehu ring plain, in order to improve the record of known events. The lithologic record is principally one of lahar deposits interbedded with datable andesitic tephras, loesses, paleosols, and rhyolitic marker beds, allowing a chronological reconstruction of volcanic events in the region during the last 120 000 yr. The main laharic surfaces include the extensive Porewan-aged (>65 000 yr B.P.) uplifted Erua plateau (Waimarino Formation, new) and voluminous Ratan-Ohakean (10 000-65 000 yr B.P.) sequences of stacked diamictons east of the Waimarino Fault (Horopito Formation, new, and Te Heuheu Formation). A marked change in eruptive style occurred around 10 000 yr B.P. when pumiceous pyroclastic flows were emplaced to the east and the west of the Mt Ruapehu cone (Taurewa Eruptive Episode). At about this time, river entrenchment into the Ohakean surface began. Holocene lahar deposits are preserved only in the Mangaturuturu and Mangawhero catchments where they are confined to riparian strips. In the Mangawhero catchment a mid-Holocene debris flow unit (Turoa diamicton) contains numerous jigsaw-jointed bombs and vitric fragments, indicative of a coeval vulcanian eruption. In historical time, only lahars in 1975 left recognisable deposits in the Mangaturuturu catchment. Thus, the potential for long-term preservation of modern, smallsize sandy diamictons is strictly limited on andesite stratovolcanoes such as Ruapehu.

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confidence: 81%

Quaternary lahar stratigraphy of the western Ruapehu ring plain, New Zealand

Lecointre

Neall

Palmer

1998

New Zealand Journal of Geology and Geophysics

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“…Like the explosions that produce them, breadcrust bombs have been variably interpreted to reflect either quenching of magma by external water (e.g., Fisher and Schmincke 1984;Francis 1993) or delayed vesiculation of partially degassed magma (e.g., Turcotte et al 1990;Hoblitt and Harmon 1993;Yamagishi and Feebrey 1994). Studies that invoke a magmatic origin for this bomb type vary in explanations of the mechanism by which breadcrusting occurs.…”

Section: Introductionmentioning

confidence: 97%

“…In a different volcanic setting, Polacci et al (2001) proposed that breadcrusting of pumiceous clasts produced during the June 15 climactic eruption of Pinatubo volcano, 1991, was promoted by locally high temperatures and lower volatile content. Additionally, Yamagishi and Feebrey (1994) hypothesized that unusual breadcrust bombs with vesicular outer rinds and dense interiors from Tokachidake volcano, Japan, reflect pre-eruptive magma degassing along cracks beneath an impermeable cap. Although different in specifics, all three recent models for vulcanian breadcrust-bomb formation require some amount of pre-eruptive volatile loss.…”

Section: Introductionmentioning

confidence: 99%

Breadcrust bombs as indicators of Vulcanian eruption dynamics at Guagua Pichincha volcano, Ecuador

Wright

Cashman

Rosi³

et al. 2006

Bull Volcanol

134

172

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Vulcanian eruptions are common at many volcanoes around the world. Vulcanian activity occurs as either isolated sequences of eruptions or as precursors to sustained explosive events and is interpreted as clearing of shallow plugs from volcanic conduits. Breadcrust bombs characteristic of Vulcanian eruptions represent samples of different parts of these plugs and preserve information that can be used to infer parameters of pre-eruption magma ascent. The morphology and preserved volatile contents of breadcrust bombs erupted in 1999 from Guagua Pichincha volcano, Ecuador, thus allow us to constrain the physical processes responsible for Vulcanian eruption sequences of this volcano. Morphologically, breadcrust bombs differ in the thickness of glassy surface rinds and in the orientation and density of crack networks. Thick rinds fracture to create deep, widely spaced cracks that form large rectangular domains of surface crust. In contrast, thin rinds form polygonal networks of closely spaced shallow cracks. Rind thickness, in turn, is inversely correlated with matrix glass water content in the rind. Assuming that all rinds cooled at the same rate, this correlation suggests increasing bubble nucleation delay times with decreasing pre-fragmentation water content of the melt. A critical bubble nucleation threshold of 0.4-0.9 wt% water exists, below which bubble nucleation does not occur and resultant bombs are dense. At pre-fragmentation melt H 2 O contents of >~0.9 wt%, only glassy rinds are dense and bomb interiors vesiculate after fragmentation. For matrix glass H 2 O contents of ≥1.4 wt%, rinds are thin and vesicular instead of thick and non-vesicular. A maximum measured H 2 O content of 3.1 wt% establishes the maximum pressure (63 MPa) and depth (2.5 km) of magma that may have been tapped during a single eruptive event. More common H 2 O contents of ≤1.5 wt% suggest that most eruptions involved evacuation of ≤1.5 km of the conduit. As we expect that substantial overpressures existed in the conduit prior to eruption, these depth estimates based on magmastatic pressure are maxima. Moreover, the presence of measurable CO 2 (≤17 ppm) in quenched glass of highly degassed magma is inconsistent with simple models of either open-or closed-system degassing, and leads us instead to suggest re-equilibration of the melt with gas derived from a deeper magmatic source. Together, these observations suggest a model for the repeated Vulcanian eruptions that includes (1) evacuation of the shallow conduit during an individual eruption, (2) depressurization of magma remaining in the conduit accompanied by opensystem degassing through permeable bubble networks, (3) rapid conduit re-filling, and (4) dome formation prior to the subsequent explosion. An important part of this process is densification of upper conduit magma to allow repressurization between explosions. At a critical overpressure, trapped pressurized gas fragments the nascent impermeable cap to repeat the process.

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“…Mapped deposits from past eruptions are often not symmetrical around the vent, reflecting this directionality (Minakami 1942;Fudali and Melson 1972;Steinberg and Lorenz 1983;Kilgour et al 2010;Houghton et al 2011;Gurioli et al 2013;Fitzgerald et al 2014), and are sometimes the result of the crater and surrounding topography Tsunematsu et al 2016). Detailed descriptions and maps of ballistic impact distributions are rare, but those published may contain some of the following data: maximum ballistic travel distances (Steinberg and Lorenz 1983;Robertson et al 1998;Kaneko et al 2016); the outer edges of a ballistic field (Minakami 1942;Nairn and Self 1978;Yamagishi and Feebrey 1994); and/or maximum particle (Nairn and Self 1978;Steinberg and Lorenz 1983;Robertson et al 1998;Swanson et al 2012) or crater size (Robertson et al 1998;Maeno et al 2013;Kaneko et al 2016). When isopleths of particle size are included these rarely contain individual measurements and may be severely limited by the availability of only specific mapped locations (e.g., Kilgour et al 2010;Houghton et al 2011).…”

Section: Ballistic Hazard and Risk Managementmentioning

confidence: 99%

The Communication and Risk Management of Volcanic Ballistic Hazards

Fitzgerald

Kennedy

Wilson

et al. 2017

Advances in Volcanology

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Tourists, hikers, mountaineers, locals and volcanologists frequently visit and reside on and around active volcanoes, where ballistic projectiles are a lethal hazard. The projectiles of lava or solid rock, ranging from a few centimetres to several metres in diameter, are erupted with high kinetic, and sometimes thermal, energy. Impacts from projectiles are amongst the most frequent causes of fatal volcanic incidents and the cause of hundreds of thousands of dollars of damage to buildings, infrastructure and property worldwide. Despite this, the assessment of risk and communication of ballistic hazard has received surprisingly little study. Here, we review the research to date on ballistic distributions, impacts, hazard and risk assessments and maps, and methods of communicating and managing ballistic risk including how these change with a changing risk environment. The review suggests future improvements to the communication and management of ballistic hazard.

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Ballistic ejecta from the 1988–1989 andesitic Vulcanian eruptions of Tokachidake volcano, Japan: morphological features and genesis

Cited by 20 publications

References 8 publications

Quaternary lahar stratigraphy of the western Ruapehu ring plain, New Zealand

Quaternary lahar stratigraphy of the western Ruapehu ring plain, New Zealand

Breadcrust bombs as indicators of Vulcanian eruption dynamics at Guagua Pichincha volcano, Ecuador

The Communication and Risk Management of Volcanic Ballistic Hazards

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