Influence of conduit flow mechanics on magma rheology and the growth style of lava domes

Husain, Taha; Elsworth, Derek; Voight, B.; Mattioli, G. S.; Jansma, P. E.

doi:10.1093/gji/ggy073

Cited by 13 publications

(6 citation statements)

References 54 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Structural stability modeling is therefore vital in understanding the hazard associated with, and the consequences of volcanic collapse events. This has been explored through various modeling efforts, including: analog modeling (Vidal and Merle, 2000;Cecchi et al, 2004;Tibaldi et al, 2006;Andrade and van Wyk de Vries, 2010;Nolesini et al, 2013); Limit Equilibrium Methods (LEM; Apuani et al, 2005;Simmons et al, 2005;Borselli et al, 2011;Schaefer et al, 2013;Dondin et al, 2017); Finite Element Modeling (FEM; Voight, 2000;Schaefer et al, 2013); Finite Difference Methods (FDM; Apuani et al, 2005;Le Friant et al, 2006) and Discrete Element Modeling (DEM; Morgan and McGovern, 2005a,b;Husain et al, 2014Husain et al, , 2018Harnett et al, 2018). Although modeling studies expand our knowledge of mechanisms of volcanic structural instability, they are often limited by the availability of mechanical data for edifice rock properties.…”

Section: Introductionmentioning

confidence: 99%

Evolution of Mechanical Properties of Lava Dome Rocks Across the 1995–2010 Eruption of Soufrière Hills Volcano, Montserrat

et al. 2019

View full text Add to dashboard Cite

Lava dome collapses pose a hazard to surrounding populations, but equally represent important processes for deciphering the eruptive history of a volcano. Models examining lava dome instability rely on accurate physical and mechanical properties of volcanic rocks. Here we focus on determining the physical and mechanical properties of a suite of temporally-constrained rocks from different phases of the 1995-2010 eruption at Soufrière Hills volcano in Montserrat. We determine the uniaxial compressive strength, tensile strength, density, porosity, permeability, and Young's modulus using laboratory measurements, complemented by Schmidt hammer testing in the field. By viewing a snapshot of each phase, we find the highest tensile and compressive strengths in the samples attributed to Phase 4, corresponding to a lower permeability and an increasing proportion of isolated porosity. Samples from Phase 5 show lower compressive and tensile strengths, corresponding to the highest permeability and porosity of the tested materials. Overall, this demonstrates a reliance of mechanical properties primarily on porosity, however, a shift toward increasing prevalence of pore connectivity in weaker samples identified by microtextural analysis demonstrates that here pore connectivity also contributes to the strength and Young's Modulus, as well as controlling permeability. The range in UCS strengths are supported using Schmidt hammer field testing. We determine a narrow range in mineralogy across the sample suite, but identify a correlation between increasing crystallinity and increasing strength. We correlate these changes to residency-time in the growing lava dome during the eruption, where stronger rocks have undergone more crystallization. In addition, subsequent recrystallization of silica polymorphs from the glass phase may further strengthen the material. We suggest the variation in physical and mechanical rock properties shown within the Soufrière Hills eruptive products be included in future structural stability models of the remaining oversteepened dome on Montserrat, and that consideration of rock heterogeneity and its temporal variation if possible, be made in other, similar systems.

show abstract

Section: Introductionmentioning

confidence: 99%

Evolution of Mechanical Properties of Lava Dome Rocks Across the 1995–2010 Eruption of Soufrière Hills Volcano, Montserrat

et al. 2019

View full text Add to dashboard Cite

show abstract

“…PFC has been previously used to successfully model the mechanical behaviour of rock (e.g., Potyondy and Cundall, 2004) and, recently, to model dome growth and collapse (Husain et al, 2014(Husain et al, , 2018Harnett et al, 2018;Husain et al, 2019;Harnett and Heap, 2021;Walter et al, 2022;Heap et al, 2023a). These DEM models consider a particlebased material in which circular particles interact at interparticle contacts.…”

Section: Numerical Modellingmentioning

confidence: 99%

The influence of water-saturation on the strength of volcanic rocks and the stability of lava domes

Heap

Harnett

Farquharson³

et al. 2023

Preprint

View full text Add to dashboard Cite

The rocks forming a volcano are typically saturated or partially-saturated with liquid. However, most experiments aimed at better understanding the mechanical behaviour of volcanic rocks have been performed on dry samples, and therefore most large-scale models designed to explore volcanic stability have used parameters representative for dry rock. We present a combined laboratory and modelling study in which we (1) quantify the influence of water on the mechanical behaviour of variably altered dome rocks from La Soufri&#232;re de Guadeloupe (Eastern Caribbean) and (2) use these new laboratory data to investigate the influence of water on dome stability. Our laboratory data show that the ratio of wet to dry uniaxial compressive strength (UCS) and Young's modulus are ~0.95&#8211;0.30 and ~1.00&#8211;0.10, respectively. In other words, the rocks were all weaker when saturated with water. We also find that the ratio of wet to dry UCS decreases with increasing alteration (the wt% of secondary minerals). Micromechanical modelling suggests that the observed water-weakening is the result of a decrease in fracture toughness (KIC) in the presence of water. We also find that the ratio of wet to dry KIC&#160;decreases with increasing alteration, explaining why water-weakening increases with alteration. To explore the influence of water saturation on dome stability, we numerically generated lava domes using the experimental data corresponding to dry unaltered and altered rock, in Particle Flow Code. The strength of the dome-forming rocks was then reduced to values corresponding to wet conditions. Our modelling showed that, although the stability of the unaltered dome was not influenced by water saturation, large displacements were observed for the altered dome. Additional modelling in which we modelled a buried alteration zone within an unaltered dome showed that higher displacements were observed when the dome was water saturated. We conclude that (1) the presence of water reduces the UCS and Young's modulus of volcanic rock, (2) larger decreases in UCS in the presence of water are observed for altered rocks, and (3) large-scale dome stability modelling suggests that the stability of a dome can be compromised by the presence of water if the dome is altered or contains an altered zone. These conclusions highlight that the degree of alteration and water saturation should be monitored at active volcanoes worldwide, and that large-scale models should use values for water-saturated rocks when appropriate.

show abstract

“…Iverson (1990) highlighted the importance of the thermal carapace in determining the morphology of domes. The role of the surface cooling and the carapace formation were analysed in laboratory and numerical experiments (e.g., Fink and Griffiths, 1998;Griffiths, 2000;Hale and Wadge, 2003;Hale et al, 2007;Hale, 2008;Husain et al, 2014Husain et al, , 2018Husain et al, , 2019Harnett et al, 2018).…”

Section: Lava Dome Carapacementioning

confidence: 99%

Lava Dome Morphology and Viscosity Inferred From Data-Driven Numerical Modeling of Dome Growth at Volcán de Colima, Mexico During 2007-2009

et al. 2021

View full text Add to dashboard Cite

Magma extrusion, lava dome growth, collapse of domes, and associated pyroclastic flow hazards are among important volcanological studies. In this paper, we analyze the influence of the magma viscosity and discharge rates on the lava dome morphology at Volcán de Colima in Mexico during a long dome-building episode lasting from early 2007 to fall 2009 without explosive dome destruction. Camera images of the lava dome growth together with recorded volumes of the erupted lava have been used to constrain numerical modeling and hence to match the history of the dome growth by nudging model forecasts to observations. Our viscosity model incorporates crystal growth kinetics and depends on the characteristic time of crystal content growth (or CCGT) and the crystal-free magma viscosity. Initially, we analyze how this viscosity, CCGT, and the rate of lava extrusion influence the morphology of the growing dome. Several model scenarios of lava dome growth are then considered depending on the crater geometry, the conduit location, the effective viscosity of dome carapace, and the extrusion rates. These rates are determined either empirically by optimizing the fit between the morphological shape of modeled domes and that of the observed dome or from the recorded lava dome volumes. The maximum height of the modeled lava dome and its horizontal extent are in a good agreement with observations in the case of the empirically-derived extrusion rates. It is shown that the topography of the crater at Volcán de Colima is likely to be inclined toward the west. The viscosity of the modeled lava dome (∼1012 Pa s) is in a good agreement with the effective viscosity estimated experimentally from lavas of Volcán de Colima. Due to the interplay between the lava extrusion and the gravity forces, the dome reaches a height threshold, and after that a horizontal gravity spreading starts to play an essential role in the lava dome evolution. The model forecasts that the dome carapace of higher viscosity (∼1014 Pa s) influences the dome growth and its morphology during long dome-building episodes by retarding horizontal advancement and developing steep-sided eastern edge of the dome at the volcano. The developed model can be used in assessments of future effusive eruptions and lava dome growth at Volcán de Colima or elsewhere. History matching modeling of lava dome growth sheds a light on dynamic processes inside the dome and may assist in assessing stress state in the dome carapace and in forecasting the dome failures.

show abstract

Influence of conduit flow mechanics on magma rheology and the growth style of lava domes

Cited by 13 publications

References 54 publications

Evolution of Mechanical Properties of Lava Dome Rocks Across the 1995–2010 Eruption of Soufrière Hills Volcano, Montserrat

Evolution of Mechanical Properties of Lava Dome Rocks Across the 1995–2010 Eruption of Soufrière Hills Volcano, Montserrat

The influence of water-saturation on the strength of volcanic rocks and the stability of lava domes

Lava Dome Morphology and Viscosity Inferred From Data-Driven Numerical Modeling of Dome Growth at Volcán de Colima, Mexico During 2007-2009

Contact Info

Product

Resources

About