An experimental investigation of sill formation and propagation in layered elastic media

Kavanagh, Janine; Menand, Thierry; Sparks, R. S. J.

doi:10.1016/j.epsl.2006.03.025

Cited by 350 publications

(309 citation statements)

References 43 publications

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“…Tensile stresses that are generated in the encasing rocks may eventually overcome their strength. If this happens, we expect that magma induces fracturing in the horizontal direction and generates a sill, as illustrated in laboratory experiments [Rivalta et al, 2005;Kavanagh et al, 2006]. One must also imagine that, in reality, the dike extends over a finite horizontal distance and propagates laterally as it rises.…”

Section: Minimum Thickness Of Low Density Rocks For Sill Inceptionmentioning

confidence: 99%

“…Indeed, one limitation of the Kavanagh et al [2006] experiments is that the magma overpressure was set at arbitrary values. We note that the only experiment that had a density inversion involved an upper layer of small thickness, such that the magma overpressure could not rise to large values.…”

Section: Density Versus Rigidity Control On Sill Emplacementmentioning

confidence: 99%

“…[44] In laboratory experiments of hydraulic fracturing through two layers, Kavanagh et al [2006] were not able to generate sills by a density inversion (i.e. such that magma is negatively buoyant in the upper layer).…”

Section: Density Versus Rigidity Control On Sill Emplacementmentioning

confidence: 99%

“…[31] We are interested in cases where the internal magma overpressure is sufficient to fracture the dike walls and induce a laterally propagating sill, as illustrated in the experiments of Rivalta et al [2005] and Kavanagh et al [2006].…”

Section: Sill Formationmentioning

confidence: 99%

“…[4] To our knowledge, propagation through layered media has only been studied in the laboratory [Rivalta et al, 2005;Kavanagh et al, 2006]. These studies have dealt with only two layers and a restricted range of layer thicknesses.…”

Section: Introductionmentioning

confidence: 99%

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Dike propagation through layered rocks

Taisne

Jaupart

2009

J. Geophys. Res.

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[1] Dike penetration through a succession of upper crustal layers with different densities is studied with a new numerical code. For an individual layer to significantly affect dike ascent, its thickness must be of order 1 when scaled to the characteristic length-scale for the inflated nose region that develops below the dike tip. This characteristic length is L* / (mQ) 1/6 (G/(1 À n)) 1/2 (Drg) À2/3 , where m and Dr are the viscosity and buoyancy of magma, G and n are elastic moduli for the encasing rocks, Q is the magma flow rate and g gravity. For basaltic dikes, L* is %1 km, which is of the same order of magnitude as the typical thickness of sedimentary strata and volcanic deposits. In such conditions, dike ascent proceeds irregularly, with large changes of velocity and width at an interface. Scaling laws for the ascent rate and dike width are derived. Penetration through low-density layers is determined by a local buoyancy balance in the inflated nose region of the dike, independently of the total buoyancy of the magma column between source and tip. In such conditions, a dike develops an internal overpressure that may be large enough to generate a horizontally propagating sill. For this to occur, the thickness of the low-density layers must exceed a threshold value, which depends only on the rock strength and on the average negative buoyancy of magma. For basaltic melt, we estimate that this threshold thickness cannot be less than about 700 m and is 2 km on average.

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Section: Minimum Thickness Of Low Density Rocks For Sill Inceptionmentioning

confidence: 99%

Section: Density Versus Rigidity Control On Sill Emplacementmentioning

confidence: 99%

Section: Density Versus Rigidity Control On Sill Emplacementmentioning

confidence: 99%

Section: Sill Formationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Dike propagation through layered rocks

Taisne

Jaupart

2009

J. Geophys. Res.

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Regional controls on magma ascent and storage in volcanic arcs

Chaussard

Amelung

2014

Geochem. Geophys. Geosyst.

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Understanding the controls for magma ascent and storage depth is important for volcanic hazard assessment. Regional differences in the depths of magma storage between volcanic arcs suggest that the settings of subduction zones and of overriding plates influence how magma ascends through the crust. Here we use a compilation of data for 70 volcanoes in 15 volcanic regions to better understand the geodynamic controls on magma storage. We describe the subduction system, which consists of the subducting slab, the mantle wedge, and the upper plate with 12 parameters encompassing the kinematics of the subduction, the structure and geometry of the slab, the timing of the subduction, the thermal structure of the slab, the upperplate crustal structure, its stress regimes, and its thermal structure. We find that the magma reservoir depths correlate with the upper-plate crustal structure and with the stress regimes. Shallow reservoirs (<5 km depths) are 52% more common in young Tertiary crust than in old Precambrian crust and 42% more common in thin crust (<25 km) than in thick crust (>45 km). Similarly, shallow magma reservoirs are 33-69% more common in extensional and strike-slip stress regimes that in compressional regimes. This illustrates the effect of buoyancy for magma ascent as well as the importance of stress regime and preexisting structures.

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Conditions and threshold for magma transfer in the layered upper crust: Insights from experimental models

Ritter

Acocella

Ruch

et al. 2013

Geophysical Research Letters

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Magma transfer, i.e., dike propagation, is partly controlled by Young's modulus (elasticity) contrasts (ratio upper layer to lower layer modulus) in the host rock. Here we try to better constrain the elasticity contrasts controlling the propagation velocity of dikes and their arrest. We simulate dike propagation in layered elastic media with different elasticity contrasts. Salted gelatin and water represent host rock and magma, respectively. For common density ratios between magma and host rock (~1.1), velocity variations are observed and a critical threshold in the elasticity contrast between layers results in the Young's modulus ratio of 2.1 ± 0.6. Naturally occurring elasticity contrasts can be much higher than this experimental threshold, suggesting that dike arrest due to heterogeneous elastic host rock properties is more frequent than expected. Examples of recently deflected or stalled dikes inside volcanoes and the common presence of high‐velocity bodies below volcanoes suggest that better defining elasticity contrasts below volcanoes helps in forecasting eruptions.

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An experimental investigation of sill formation and propagation in layered elastic media

Cited by 350 publications

References 43 publications

Dike propagation through layered rocks

Dike propagation through layered rocks

Regional controls on magma ascent and storage in volcanic arcs

Conditions and threshold for magma transfer in the layered upper crust: Insights from experimental models

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