Pyroclastic Flow from Soufri&amp;#232;re Hills Volcano, Montserrat: Solid Block Model

Nikolkina, Irina; Zahibo, Narcisse; Talipova, Tatiana; Pelinovsky, Efim

doi:10.4236/ijg.2011.23035

Cited by 2 publications

(2 citation statements)

References 29 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The small values of the friction coefficient needed to reproduce large pyroclastic flows in Montserrat and more generally large landslides worldwide is in agreement with previous studies [Mangeney et al, 2000;Heinrich et al, 2001;Bayarri et al, 2009;Nikolkina et al, 2011;Pirulli et al, 2007;Lucas et al, 2014]. As shown by Lucas et al [2014], the friction weakening with volume can be the result of a friction decrease with velocity or other dynamic parameters as also suggested for earthquakes.…”

Section: Resultssupporting

confidence: 90%

Friction weakening in granular flows deduced from seismic records at the Soufrière Hills Volcano, Montserrat

et al. 2015

View full text Add to dashboard Cite

Accurate modeling of rockfalls and pyroclastic flows is still an open issue, partly due to a lack of measurements related to their dynamics. Using seismic data from the Soufrière Hills Volcano, Montserrat, and granular flow modeling, we show that the power laws relating the seismic energy Es to the seismic duration ts and relating the loss of potential energy ΔEp to the flow duration tf are very similar, like the power laws observed at Piton de la Fournaise, Reunion Island. Observations showing that tf≃ts suggest a constant ratio Es/ΔEp≃10−5. This similarity in these two power laws can be obtained only when the granular flow model uses a friction coefficient that decreases with the volume transported. Furthermore, with this volume‐dependent friction coefficient, the simulated force applied by the flow to the ground correlates well with the seismic energy, highlighting the signature of this friction weakening effect in seismic data.

show abstract

Section: Resultssupporting

confidence: 90%

Friction weakening in granular flows deduced from seismic records at the Soufrière Hills Volcano, Montserrat

et al. 2015

View full text Add to dashboard Cite

show abstract

“…While the topography is well known, and the basal friction angle can be estimated to be of the order of 12-16.58 (Nikolkina et al 2011), data of initial velocities of the PDCs from the SHV are poorly documented. Average velocities of propagation have been measured in the range of 5-35 m s 21 Cole et al 2002;Carn et al 2004), but modelling suggests that initial velocities of dome-collapse-induced PDCs can be much higher, reaching approximately 50-70 m s 21 (Wadge et al 1998;Hooper & Mattioli 2001).…”

Section: Thermo-acoustic Tracking Of the Propagation Of Pdcsmentioning

confidence: 99%

Chapter 9 Thermal, acoustic and seismic signals from pyroclastic density currents and Vulcanian explosions at Soufrière Hills Volcano, Montserrat

Donne

Ripepe

Angelis

et al. 2014

Memoirs

View full text Add to dashboard Cite

Abstract:We show two examples of how integrated analysis of thermal and infrasound signal can be used to obtain, in real time, information on volcanic activity. Soufrière Hills Volcano (SHV) on Montserrat offers the opportunity to study a large variety of processes related to lava-dome activity, such as pyroclastic density currents (PDCs) and large Vulcanian eruptions. Infrasound and thermal analysis are used to constrain the propagation of PDCs and their velocities, which are calculated here to range between 15 and 75 m s 21 . During the Vulcanian eruption of 5 February 2010, infrasound and thermal records allow us to identify an approximately 13 s seismic precursor possibly related to the pressurization of the conduit before the explosion onset. The associated very long period (VLP) seismic signal is correlated with the gas-thrust phase detected by thermal imagery, and may reflect a change in the upward momentum induced by the mass discharge. Moreover, from infrasound and thermal analysis, we estimate a gas-thrust phase lasting 22 s, with an initial plume velocity of approximately 170 m s 21 and a mean volumetric discharge rate of 0.3 Â 10 5 -9.2 Â 10 5 m 3 s 21 . This information provided in real time gives important input parameters for modelling the tephra dispersal into the atmosphere.Gold Open Access: This article is published under the terms of the CC-BY 3.0 license.Lava dome eruptions represent a style of volcanism of distinctive interest because of their potential consequences, such as the generation of pyroclastic density currents (PDCs) down the volcano's flanks and large explosive eruptions following partial-dome collapse. Lava domes are formed by silica-rich lava that is too viscous to flow and, instead, builds-up over the point of extrusion. The hazards from lava-dome eruptions are well known owing to unpredictable transitions from the slow extrusion of viscous lava to vigorous explosions, and to the propensity of lava domes to suddenly collapse, spawning devastating PDCs down the flanks of volcanic edifices (Young et al. 1998;. As a lava dome grows, parts of it may collapse because of gravitational instability or as the result of gas explosions within the dome itself, thus forming PDCs. The ability to detect and track the propagation of these fast-moving density currents is of utmost importance in understanding the evolution of lava dome eruptions and mitigating related hazards.Methods for the location of PDCs, based on seismic amplitudes, have been proposed in the past (e.g. Jolly et al. 2002) and have proved quite effective for the characterization of large collapse events. These techniques require dense seismic networks and optimal azimuthal coverage; both conditions are rarely met on lava dome volcanoes where seismic networks are sparse because of the restrictions imposed by rough terrain and eruption hazards. The use of seismic amplitudes requires understanding of local site effects and frequency-dependent attenuation, thus introducing another layer of complexity. Finally, these methods are ...

show abstract

Pyroclastic Flow from Soufrière Hills Volcano, Montserrat: Solid Block Model

Cited by 2 publications

References 29 publications

Friction weakening in granular flows deduced from seismic records at the Soufrière Hills Volcano, Montserrat

Friction weakening in granular flows deduced from seismic records at the Soufrière Hills Volcano, Montserrat

Chapter 9 Thermal, acoustic and seismic signals from pyroclastic density currents and Vulcanian explosions at Soufrière Hills Volcano, Montserrat

Contact Info

Product

Resources

About