Mobility of pyroclastic flows and surges at the Soufriere Hills Volcano, Montserrat

Calder, Eliza S.; Cole, Paul; Dade, W. Brian; Druitt, Timothy H.; Hoblitt, Richard P.; Huppert, Herbert E.; Ritchie, L. J.; Sparks, R. S. J.; Young, S. R.

doi:10.1029/1999gl900051

Cited by 156 publications

(132 citation statements)

References 18 publications

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“…Generation of finer particles enhances the number of particles in the suspended load region of the flow, where turbulence and particle-particle interactions maintain fine particles in a suspension. Suspended load currents can detach from the basal, particle dense layer, surmount topography, and travel further than some confined dense flows [Calder et al, 1999;Dufek and Bergantz, 2007b;Miller and Smith, 1977]. Scaling analyses indicate that both velocity and runout distance should increase as the mass of fine particles increases in the suspended load [Britter and Simpson, 1978;Bursik and Woods, 1996;Dade and Huppert, 1995;Simpson, 1997].…”

Section: Introductionmentioning

confidence: 99%

“…The rounding of particles can represent a considerable loss of the volume fraction of the initial particle; for instance, the reduction of a cube to sphere of the same diameter is approximately a $48% volume reduction. Rounding of clasts has been observed for a variety of compositions (andesite -rhyolite) and eruption styles (e.g., vulcanian, column collapse, dome collapse) [Allen, 2001;Calder et al, 1999Calder et al, , 2000.…”

Section: Introductionmentioning

confidence: 99%

“…The largest of these density currents produce massive ignimbrites and are the most voluminous single ash sources to the atmosphere, having potentially dramatic effects on climate [Perkins and Nash, 2002;Self, 2006;Sparks and Wilson, 1976;Valentine and Wohletz, 1989;Walker, 1981;Wilson and Hildreth, 1997]. More common, and smaller volume, pyroclastic density currents are an immediate hazard to surrounding population centers, and the associated ash can induce long-term respiratory problems [Calder et al, 1999;Cole et al, 2002;Edmonds et al, 2006;Fisher et al, 1987;Horwell and Baxter, 2006]. These flows are also agents of rapid landscape evolution near steep volcanic edifices.…”

Section: Introductionmentioning

confidence: 99%

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In situ production of ash in pyroclastic flows

Dufek

Manga

2008

J. Geophys. Res.

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[1] Abrasion and comminution of pumice clasts during the propagation of pyroclastic flows have long been recognized as a potential source for the enhanced production of volcanic ash, however, their relative importance has eluded quantification. The amount of ash produced in situ can potentially affect runout distance, deposit sorting, the volume of ash introduced in the upper atmosphere, and internal pore pressure. We conduct a series of laboratory experiments on the collisional and frictional production of ash that may occur during different regimes of pyroclastic flow transport. Ash produced in these experiments is predominately 10-100 microns in size and has similar morphology to tephra fall ash from Plinian events. We find that collisional ash production rates are proportional to the square of impact velocity. Frictional ash production rates are a linear function of the velocity of the basal, particle-enriched bed load region of these flows. Using these laboratory experiments we develop a subgrid model for ash production that can be included in analytical and multiphase numerical procedures to estimate the total volume of ash produced during transport. We find that for most flow conditions, 10-20% of the initial clasts comminute into ash with the percentage increasing as a function of initial flow energy. Most of the ash is produced in the high-energy regions near the flow inlet, although flow acceleration on steep slopes can produce ash far from the vent. On level terrain, collisionally and frictionally produced ash generates gravity currents that detach from the main flow and can more than double the effective runout distance of these flows. Ash produced at the frictional base of the flow and in the collisional upper regions of the flow can be redistributed through the entirety of the flow, although frictionally produced ash accumulates preferentially near its source in the bed load. Flows that descend steep slopes produce the majority of their ash in the collisonally dominant flow head and flow snouts likely develop subangular to rounded pumice during this process.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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In situ production of ash in pyroclastic flows

Dufek

Manga

2008

J. Geophys. Res.

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“…The range of maximum temperatures found for this deposit (250°-350°C, Figure 8a), a few hours after the emplacement, fitted within the range obtained with the thermal remnant magnetization technique on different types of pyroclastic density currents from the A.D. 79 eruption of Vesuvius [Cioni et al, 2004] and within the range of temperature for derived pyroclastic flows at Montserrat, measured within 72 h of deposit emplacement [Calder et al, 1999]. between 29 December 2002 and 14 February 2003, regular daily measurements were carried out.…”

Section: Thermal Surveysmentioning

confidence: 94%

The Eruptive Activity of 28 and 29 December 2002

Pioli

Rosi

Calvari

et al. 2013

Geophysical Monograph Series

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At 1820 UT of 28 December 2002, an eruptive vent opened on the NE flank of the Sciara del Fuoco (SdF) at 600 m above sea level, marking the onset of the 2002-2003 eruptive crisis of Stromboli volcano. The first eruptive hours were characterized by mild spattering and effusive activity from the new vent and the summit vent at crater 1. Gravitational instability processes also determined the partial collapse of NE walls of the summit cone (crater 1). Pyroclastic material partly accumulated on the NE part of the SdF and partly flowed downslope and reached the sea at Spiaggia dei Gabbiani, forming a ~4-m-thick, reddish avalanche, that was soon covered by a lava flow emitted in the following hours. In this paper, we describe the first hours of activity through eyewitnesses' reports, geophysical monitoring, field and laboratory studies, of the erupted pyroclastic material and lava flows. Daily temperature measurements were carried out on the avalanche deposit formed by the flow of scoria along the SdF, using a handheld thermal camera mainly during helicopter surveys. A fast cooling rate was typical of the deposit surface, and a slow cooling rate was representative of its inner portion.

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“…Pyroclastic flows are denser than surges and generally form more massive deposits, poorly sorted, filling the valleys. Surges can be associated with a pyroclastic flow, located at the periphery of this flow or generated by ash cloud surmounting it (case of Mt St Helens, Mellors et al (1988) and the Soufriere Hills volcano, Calder et al (1999).…”

Section: Pyroclastic Density Currents Depositsmentioning

confidence: 99%

Hazards from Pyroclastic Density Currents at Mount Bamenda (West-Cameroon, Cameroon Volcanic Line): Mapping and Assessment by AMS Method

Dedzo¹,

Kamgang²,

Njonfang³

et al. 2015

American Journal of Geoscience

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Hazards related to pyroclastic density current continue to raise victims on many volcanoes in our planet. The Cameroon is not spared to this type of hazard because deposits of pyroclastic flows and surges are found on Mount Bamenda; products of this volcano are relatively young (27-0 Ma). Besides Mount Bamenda, Mounts Bambouto and Oku are the only volcanoes located in the central part of the Cameroon Volcanic Line where these ignimbritic deposits are found. Several factors highlight dangerousness and damage that can cause ignimbritic flows on the flanks of this volcano. This is essentially the high aspect ratio of these ignimbrites, the important population (about 750,000 people) that lives on the slopes and around the volcano. In order to have an idea of a nowadays ignimbritic eruption scenario on Bamenda volcano, the Anisotropy of Magnetic Susceptibility (ASM) method is used in this study to highlight the palaeoflow in ancient deposits of ignimbrites which are mostly discontinuous and isotropic. Results of AMS study are used to produce map of hazards and assess risks that may be related with such eruptions in Bamenda volcano.

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Mobility of pyroclastic flows and surges at the Soufriere Hills Volcano, Montserrat

Abstract: Abstract.The

Cited by 156 publications

References 18 publications

In situ production of ash in pyroclastic flows

In situ production of ash in pyroclastic flows

The Eruptive Activity of 28 and 29 December 2002

Hazards from Pyroclastic Density Currents at Mount Bamenda (West-Cameroon, Cameroon Volcanic Line): Mapping and Assessment by AMS Method

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