The flow dynamics of an extremely large volume pyroclastic flow, the 2.08-Ma Cerro Galán Ignimbrite, NW Argentina, and comparison with other flow types

Fernand, Raymond Alexander; Wright, Heather; Folkes, Chris B.; Lesti, Chiara; Porreca, Massimiliano; Giordano, Guido; Viramonte, J.

doi:10.1007/s00445-011-0564-y

Cited by 108 publications

(79 citation statements)

References 74 publications

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“…These are extremely damaging fast-moving (10s to 100s of km/h; Lube et al, 2007;Cas et al, 2011;Komorowski et al, 2013;Roche, 2015), often quite hot flows (>100°C, generally 300-700°C) typically formed from volcanic column collapse or lava dome collapse (Dufek et al, 2015). Damage to the built environment is driven by dynamic pressure, P dyn (Spence et al, 2004;Jenkins et al, 2014a), which is a function of flow density, ρ, and velocity, v (Valentine, 1998):…”

Section: Pyroclastic Density Currents (Pdcs)mentioning

confidence: 99%

Evaluating the impacts of volcanic eruptions using RiskScape

et al. 2017

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RiskScape is a free multi-hazard risk assessment software programme jointly developed by GNS Science and the National Institute of Water and Atmospheric Research (NIWA) in New Zealand. RiskScape has a modular structure, with hazard layers, assets, and loss functions prepared separately. While RiskScape was originally developed for New Zealand, given suitable hazard and exposed asset information, RiskScape can be run anywhere in the world. Volcanic hazards are among the many hazards considered by RiskScape. We first present RiskScape's framework for all hazards, and then describe in more detail the five volcanic hazards -tephra deposition, pyroclastic density currents, lava flows, lahars, and edifice construction/excavation. We describe how loss functions were selected and developed. We use a scenario example to illustrate not only how RiskScape's volcanic module works but also how RiskScape can be used to compare across natural hazards.

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Section: Pyroclastic Density Currents (Pdcs)mentioning

confidence: 99%

Evaluating the impacts of volcanic eruptions using RiskScape

et al. 2017

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“…Como lo sugieren Smith y Cole (1997) y Branney et al (1992), columnas eruptivas bajas tales como las de tipo 'boiling-over' pierden menos calor por mezcla con aire atmosférico en comparación con columnas plininas altas y la temperatura se mantiene elevada en los resultantes flujos piroclásticos. Muchas de las características mencionadas son semejantes a las que se presentan en las ignimbritas asociadas a las calderas de la Puna Guzmán y Petrinovic, 2010;Cas et al, 2011).…”

Section: Ignimbrita La Plateadaunclassified

Mecanismos eruptivos y procesos depositacionales del Grupo Choiyoi en el área de Las Caletas, Cordillera Frontal de San Juan, Argentina

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Vallecillo

2014

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“…These observations, together with lab-scale experiments, indicate that the main factor in driving sustained fluidization is long-lived gas *e-mail: jmillan@us.es pore pressure presumably due to hampered diffusion by the reduced permeability of the trapped gas through large amounts of fine ash [5]. (2) aluminium shaft, (3) flexible coupling (cardan), (4) step motor and controller, (5) vibrator (Tira TV 52120), (6) accelerometer, (7) halogen lamp, (8) CCD camera, (9) optical antivibration table, (10) desktop computer, (11) oscilloscope, (12) power amplifier, ( 13) function generator.…”

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confidence: 95%

“…These dense granular flows are chiefly characterized by their high mobility. Usually, extraordinary long runout distances over 100 km and across topographic obstacles are reached [2][3][4][5]. A possible mechanism responsible for such astonishing behavior is sustained fluidization caused by the enhancement of pore gas pressure [2,5].…”

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confidence: 99%

“…Usually, extraordinary long runout distances over 100 km and across topographic obstacles are reached [2][3][4][5]. A possible mechanism responsible for such astonishing behavior is sustained fluidization caused by the enhancement of pore gas pressure [2,5]. Since pyroclastic flows commonly contain large amounts of fine ash and light pumice rock fragments, their flow dynamics could be indeed determined by the prevalence of the interstitial gas drag force on the particles over their weight.…”

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Dynamical weakening of pyroclastic flows by mechanical vibrations

2017

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Abstract. Dynamical weakening of dense granular flows plays a critical role on diverse geological events such as seismic faulting and landslides. A common feature of these processes is the development of fluidsolid relative flows that could lead to fluidization by hydrodynamic viscous stresses. Volcanic ash landslides (pyroclastic flows) are characterized by their high mobility often attributed to fluidization of the usually fine and/or low-density particles by their interaction with the entrapped gas. However, the physical mechanism that might drive sustained fluidization of these dense granular flows over extraordinarily long runout distances is elusive. The behavior of volcanic ash in a slowly rotating drum subjected to mechanical vibrations shown in this work suggests that fluid-particle relative oscillations in dense granular flows present in volcanic eruption events can promote pore gas pressure at reduced shear rates as to sustain fluidization. Pyroclastic flows, triggered by the collapse of lava domes and explosive volcanic eruptions, represent a serious hazard for densely populated areas around volcanoes. These dense granular flows are chiefly characterized by their high mobility. Usually, extraordinary long runout distances over 100 km and across topographic obstacles are reached [2][3][4][5]. A possible mechanism responsible for such astonishing behavior is sustained fluidization caused by the enhancement of pore gas pressure [2,5]. Since pyroclastic flows commonly contain large amounts of fine ash and light pumice rock fragments, their flow dynamics could be indeed determined by the prevalence of the interstitial gas drag force on the particles over their weight. The role of fluidization on the extraordinary mobility of pyroclastic flows is suggested by the typical signature observed in the patterns of prehistoric ignimbrite deposits indicating negligible friction and suppressed turbulence at the depositional boundary layer [3]. It is believed that long runout landslides involving large release and deposit volumes (> 10 6 m 3 ) are associated with high flow velocities ranging from tens to hundreds of m/s [4]. At such high velocities granular flows of fine and/or light particles become fluidized by the entrapped gas at the avalanche front and acquire the behavior of a low viscosity fluid lacking any resistance to shear [6]. Recent observations of sediments from dense pre-historic pyroclastic flows showing the signatures of fluidization and traveling distances over 170 km demonstrate relatively modest and uniform velocities ( < 10 m/s) suggesting that high velocities are not necessary for fluidization of pyroclastic flows [5]. These observations, together with lab-scale experiments, indicate that the main factor in driving sustained fluidization is long-lived gas

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The flow dynamics of an extremely large volume pyroclastic flow, the 2.08-Ma Cerro Galán Ignimbrite, NW Argentina, and comparison with other flow types

Cited by 108 publications

References 74 publications

Evaluating the impacts of volcanic eruptions using RiskScape

Evaluating the impacts of volcanic eruptions using RiskScape

Mecanismos eruptivos y procesos depositacionales del Grupo Choiyoi en el área de Las Caletas, Cordillera Frontal de San Juan, Argentina

Dynamical weakening of pyroclastic flows by mechanical vibrations

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