Stress fields generating ring faults in volcanoes

Guðmundsson, Ágúst; Martı́, Joan; Turon, Elisenda

doi:10.1029/97gl01494

Cited by 90 publications

(63 citation statements)

References 15 publications

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“…Ring faults geometry is, in fact, a typical feature of volcanic systems, where magma chambers generate a local stress field triggering caldera collapse (Gudmundsson, Marti, & Turon, 1997). In glaciated environments, ring faults were observed by Branney and Gilbert (1995) in Rio de los Huemules Valley, Chile, after the eruption of Volcan Hudson.…”

Section: Ring Faultsmentioning

confidence: 99%

Recent structural evolution of Forni Glacier tongue (Ortles-Cevedale Group, Central Italian Alps)

et al. 2017

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Structural glaciology yields important details about the evolution of glacier dynamics in response to climate change. The maps provided here document the occurrence and evolution of brittle and ductile structures on the tongue of Forni Glacier, Ortles-Cevedale Group, Central Italian Alps, between 2003 and 2014. Through the remote sensing-based analysis of structures, we found evidence of brittle fractures such as crevasses, faults and ring faults, and ductile structures such as ogives at the base of the icefall in the eastern glacier tongue. Although each of the three glacier tongues have evolved differently, a reduction in flow-related dynamics and an increase in the number of collapse structures occurred over the study period. Analysis of the glacier structural evolution based on the numbers and the locations of different structures, suggest a slowdown of glacier flow on the eastern tongue. The recent evolution of the glacier also suggests that the occurrence of a disintegration scenario is likely to worsen over the next decades.ARTICLE HISTORY

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Section: Ring Faultsmentioning

confidence: 99%

Recent structural evolution of Forni Glacier tongue (Ortles-Cevedale Group, Central Italian Alps)

et al. 2017

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“…Either counteracts or adds to dominant tectonic stresses depending on the sign and intensity of the far-field stress and on the magma chamber shape and orientation (Gudmundsson, 1988(Gudmundsson, , 1998Gudmundsson et al, 1997).…”

Section: Introductionmentioning

confidence: 99%

Stress Field Control during Large Caldera-Forming Eruptions

Costa

Martı́

2016

Front. Earth Sci.

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Crustal stress field can have a significant influence on the way magma is channeled through the crust and erupted explosively at the surface. Large Caldera Forming Eruptions (LCFEs) can erupt hundreds to thousands of cubic kilometers of magma in a relatively short time along fissures under the control of a far-field extensional stress. The associated eruption intensities are estimated in the range 10 9 -10 11 kg/s. We analyse syn-eruptive dynamics of LCFEs, by simulating numerically explosive flow of magma through a shallow dyke conduit connected to a shallow magma (3-5 km deep) chamber that in turn is fed by a deeper magma reservoir (>∼10 km deep), both under the action of an extensional far-field stress. Results indicate that huge amounts of high viscosity silicic magma ( 10 7 > Pa s) can be erupted over timescales of a few to several hours. Our study provides answers to outstanding questions relating to the intensity and duration of catastrophic volcanic eruptions in the past. In addition, it presents far-reaching implications for the understanding of dynamics and intensity of large-magnitude volcanic eruptions on Earth and to highlight the necessity of a future research to advance our knowledge of these rare catastrophic events.

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“…The occurrence of explosive calderaforming events depends on the strength of the chamber walls and the depth, water content, and aspect ratio of the magma chamber [Marti et al, 2000]. Gudmundsson [1998] and Gudmundsson et al [1997] have proposed that regional loading favors the formation of ring faults. Recently, McLeod [1999] has proposed that magmatic buoyancy can also play a major However, the thermodynamic evolution of the magma chamber during a caldera-forming process is still unresolved.…”

Section: Introductionmentioning

confidence: 99%

Numerical modeling of magma withdrawal during explosive caldera‐forming eruptions

Folch¹,

Codina²,

Martı́³

2001

J. Geophys. Res.

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Abstract. We propose a simple physical model to characterize the dynamics of magma withdrawal during the course of caldera-forming eruptions. Simplification involves considering such eruptions as a piston-like system in which the host rock is assumed to subside as a coherent rigid solid. Magma behaves as a Newtonian incompressible fluid below the exsolution level and as a compressible gas-liquid mixture above this level. We consider caldera-forming eruptions within the frame of fluid-structure interaction problems, in which the flow-governing equations are written using an arbitrary Lagrangian-Eulerian (ALE) formulation. We propose a numerical procedure to solve the ALE governing equations in the context of a finite element method. The numerical methodology is based on a staggered algorithm in which the flow and the structural equations are alternatively integrated in time by using separate solvers. The procedure also involves the use of the quasi-Laplacian method to compute the ALE mesh of the fluid and a new conservative remeshing strategy. Despite the fact that we focus the application of the procedure toward modeling caldera-forming eruptions, the numerical procedure is of general applicability. The numerical results have important geological implications in terms of magma chamber dynamics during explosive caldera-forming eruptions. Simulations predict a nearly constant velocity of caldera subsidence that strongly depends on magma viscosity. They also reproduce the characteristic eruption rates of the different phases of an explosive calderaforming eruption. Numerical results indicate that the formation of vortices beneath the ring fault, which may allow mingling and mixing of parcels of magma initially located at different depths in the chamber, is likely to occur for low-viscosity magmas. Numerical results confirm that exsolution of volatiles is an efficient mechanism to sustain explosive caldera-forming eruptions and to explain the formation of large volumes of ignimbrites.

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Stress fields generating ring faults in volcanoes

Cited by 90 publications

References 15 publications

Recent structural evolution of Forni Glacier tongue (Ortles-Cevedale Group, Central Italian Alps)

Recent structural evolution of Forni Glacier tongue (Ortles-Cevedale Group, Central Italian Alps)

Stress Field Control during Large Caldera-Forming Eruptions

Numerical modeling of magma withdrawal during explosive caldera‐forming eruptions

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