The influence of cross-sectional channel geometry on rheology and flux estimates for active lava flows

Lev, Einat; James, Michael

doi:10.1007/s00445-014-0829-3

Cited by 28 publications

(17 citation statements)

References 42 publications

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“…1 and references therein, as well as Online Resource Table ESM 1). However, this simple method provides only approximate estimations of overall, or apparent, viscosity of lava flows (Lev and James 2014). More challenging are direct instrumental measurements of lava viscosity using various, commonly custombuilt viscometers.…”

Section: Introductionmentioning

confidence: 99%

Dynamics and viscosity of ‘a’a and pahoehoe lava flows of the 2012–2013 eruption of Tolbachik volcano, Kamchatka (Russia)

Belousov

Belousova

2017

Bull Volcanol

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The 2012-2013 flank eruption of Tolbachik volcano (Kamchatka) lasted 9 months and produced 0.54 km 3 of basaltic trachyandesite lava, thus becoming one of the most voluminous historical lava effusions of basic composition in subductionrelated environments globally. From March to July 2013, the volcano monotonously erupted lava of constant composition (SiO 2 = 52 wt%) with a nearly stable effusion rate of 18 m 3 /s. Despite the uniform eruptive and emplacement conditions, the dominant style of lava propagation throughout that time gradually changed from 'a'a to pahoehoe. We report results of instrumental field measurements of the 'a'a and pahoehoe flow dynamics (documented with time-lapse cameras) as well as the lava viscosity determined by flow rate and shear stress (using penetrometer) methods. Maximal propagation velocities of the 'a'a fronts ranged from 2 to 25 mm/s, and those of the pahoehoe from 0.5 to 6 mm/s. The flow front velocities of both lava types experienced short-period fluctuations that were caused by complex flow mechanics of the advancing flow lobes. Minimal viscosities of lava of the 'a'a lobes ranged from 1.3 × 10 5 to 3.3 × 10 7 Pa s (flow rate method), and those of the pahoehoe from to 5 × 10 3 to 5 × 10 4 Pa s (shear stress method). Our data include the first ever measured profiles of viscosity through the entire thickness of actively advancing pahoehoe lava lobes. We have found that both the 'a'a and pahoehoe flows were fed by identical parental lava, which then developed contrasting rheological properties, owing to differences in the process of lava transport over the ground surface. The observed transition from the dominant 'a'a to the dominant pahoehoe propagation styles occurred due to gradual elongation and branching of the lava tube system throughout the course of the eruption. Such evolution became possible because the growing lava field, composed of semisolidified flows, provided an environment for shallow subsurface intrusions and internal migrations of lava that, with time, developed into branches of the lava tube system. Based on our data, we propose phenomenological models of the 'a'a and pahoehoe flow mechanics.

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Section: Introductionmentioning

confidence: 99%

Dynamics and viscosity of ‘a’a and pahoehoe lava flows of the 2012–2013 eruption of Tolbachik volcano, Kamchatka (Russia)

Belousov

Belousova

2017

Bull Volcanol

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“…We found that changes in the crystal and bubble content do not correlate with changes in the number of channels, implying that these textural parameters do not exert a direct control on channel network architecture. However, we know from previous studies that pre-existing topography can strongly affect the apparent viscosity of lava flows due to their non-Newtonian behavior (e.g., Peterson and Tilling 1980;Lev and James 2014;Soldati et al 2016) and that crystal and bubble contents affect the degree of non-Newtonian behavior of lava (e.g., Costa et al 2009;Llewellin et al 2002;Mader et al 2013). Both morphological and rheological perspectives remain therefore necessary to fully characterize a channel-fed flow system and to adequately model its development.…”

Section: Resultsmentioning

confidence: 99%

Textural, thermal, and topographic constraints on lava flow system structure: the December 2010 eruption of Piton de la Fournaise

et al. 2018

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“…Low ψ values, on the other hand, correlate with tube formation and inflated toes. Robertson and Kerr [2012] and Lev and James [2014] include a de− tailed script for calculating for both natural and laboratory flows using the material properties, flow velocity, and environmental conditions. A re− lated characterization is given by Griffiths et al [2003], who define the parameter ϑ=Ψ(R a R 0 ), where R a is the Rayleigh number for convection within the flow, and R 0 is taken to be equal to 100 Griffiths et al [2003].…”

Section: Nd Number Definition Meaningmentioning

confidence: 99%

Analog experiments of lava flow emplacement

Lev

Rumpf

Dietterich

2019

Annals of Geophysics

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Laboratory experiments that simulate lava flows have been in use by volcanologists for many years. The behavior of flows in the lab, where "eruption" parameters, material properties, and environmental settings are tightly controlled, provides insight into the influence of various factors on flow evolution. A second benefit of laboratory lava flows is to provide a set of observations with which numeri− cal models of flow emplacement can be tested. Models of lava flow emplacement vary in mathematical approach, physical assumptions, and computational cost. Nonetheless, all models require thorough testing and evaluation, and laboratory experiments produce an ex− cellent test for models. This paper provides a primer on modern analog laboratory lava flow experiments. It reviews scaling considerations and provides quanti− tative information meant to guide future experimentalists in designing their experiments to be relevant to natural processes. Traditional and novel laboratory techniques are described, including a discussion of current limitations. New insights from recent experiments high− light the impact of topographic conditions and highlight the importance of considering bed roughness, major obstacles, and slope breaks. The influence of episodic or non−uniform effusion rate is demonstrated through recent experimental works. Lastly, the paper discusses sev− eral open questions about lava flow emplacement and the ways in which future improvements in experimental methods, such as the abil− ity to utilize three−phase suspensions and materials with complex rheologies and to image the interior of flows could help answer these.

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The influence of cross-sectional channel geometry on rheology and flux estimates for active lava flows

Cited by 28 publications

References 42 publications

Dynamics and viscosity of ‘a’a and pahoehoe lava flows of the 2012–2013 eruption of Tolbachik volcano, Kamchatka (Russia)

Dynamics and viscosity of ‘a’a and pahoehoe lava flows of the 2012–2013 eruption of Tolbachik volcano, Kamchatka (Russia)

Textural, thermal, and topographic constraints on lava flow system structure: the December 2010 eruption of Piton de la Fournaise

Analog experiments of lava flow emplacement

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