Surface Deformation in Volcanic Rift Zones

Pollard, David D.; Delaney, Paul T.; Duffield, Wendell A.; Endo, Elliot T.; Okamura, Arnold T.

doi:10.1016/b978-0-444-42198-2.50036-5

Cited by 76 publications

(107 citation statements)

References 20 publications

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“…Most previous studies that examined the mechanical interaction between magma injection and faulting assumed that the Earth behaves as an elastic half-space and simulated faulting through induced slip on presupposed dislocations in the crust (e.g., [7,8,15]). These assumptions are likely valid on short timescales, but breakdown in the case of repeated diking events over geologic time.…”

Section: Numerical Models Of Volcanic Riftingmentioning

confidence: 99%

“…However, while the mechanical interaction between magma injection and faulting has been studied on the timescale of individual dikes [7,8,[15][16][17][18], little work has been done to understand how these processes will evolve over geologic time.…”

Section: Introductionmentioning

confidence: 99%

“…Regions overlying zones of dike emplacement are characterized by normal faulting, subsidence, and graben formation (e.g., [7][8][9][10]). For example, individual diking events in Iceland have been observed to produce up to 2 m of co-intrusion slip on normal faults with little or no lava eruption [11,12].…”

Section: Introductionmentioning

confidence: 99%

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Topographic controls on dike injection in volcanic rift zones

Behn

Buck

Sacks

2006

Earth and Planetary Science Letters

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Abstract:Dike emplacement in volcanic rift zones is often associated with the injection of "bladelike" dikes, which propagate long distances parallel to the rift, but frequently remain trapped at depth and erupt only near the tip of the dike. Over geologic time, this style of dike injection implies that a greater percentage of extension is accommodated by magma accretion at depth than near the surface. In this study, we investigate the evolution of faulting, topography, and stress state in volcanic rift zones using a kinematic model for dike injection in an extending 2-D elastic-viscoplastic layer. We show that the intrusion of blade-like dikes focuses deformation at the rift axis, leading to the formation of an axial rift valley. However, flexure associated with the development of the rift topography generates compression at the base of the plate. If the magnitude of these deviatoric compressive stresses exceeds the deviatoric tensile stress associated with far-field extension, further dike injection will be inhibited. In general, this transition from tensile to compressive deviatoric stresses occurs when the rate of accretion in the lower crust is greater than 50-60% of the far-field extension rate. These results indicate that over geologic time-scales the injection of blade-like dikes is a self-limiting process in which dike-generated faulting and topography result in an efficient feedback mechanism that controls the time-averaged distribution of magma accretion within the crust.

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Section: Numerical Models Of Volcanic Riftingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Topographic controls on dike injection in volcanic rift zones

Behn

Buck

Sacks

2006

Earth and Planetary Science Letters

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“…Surface fractures are assumed to have been produced when extensi onal stresses above each dike induce linear deformation at the surface, but this me chanism has thus far been documented only for shallow dikes on Earth using linear elastic fracture mechanics and experimental modeling (e.g. Pollard & Holzhausen 1979, Pollard et al 1983, Rubin 1992. For larger dikes as well as those with tips that do not approach closer than a kilometer to the surface, numerical model ing predicts that surface deformation can be generated, but that this deformation requires a superimposed remote differential stress that predisposes fractured Full details on these and additional giant radiating swarm events are in Ernst & Buchan (1997a, 2001c.…”

Section: Evidence For Radiating Dike Swarms On Venus and Their Physicmentioning

confidence: 99%

Giant Dike Swarms: Earth, Venus, and Mars

Ernst

Grosfils

Mège

2001

Annu. Rev. Earth Planet. Sci.

300

137

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▪ Abstract Earth, Venus, and Mars all exhibit populations of giant (radiating, linear, and arcuate) mafic dike swarms hundreds to >2000 km in length. On Earth the dikes are exposed by erosion, while on Venus and Mars their presence is mainly inferred from associated volcanic morphology and surface deformation. The apparent absence of plate tectonics in the geologic record of Venus and Mars means that the observed population of swarms remains geometrically intact, while on Earth plate tectonics has fragmented swarms. About 30 giant radiating swarms have so far been identified on Earth, but with further study the number is expected to rise and may eventually coincide with the hundreds of mantle plume head events now being proposed. On Venus, at least 118 radiating swarms are distributed across the planet, and new high resolution mapping is revealing additional swarms. On Mars, up to 16 giant dike swarms are observed, most associated with the Tharsis region.

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“…Here overpressure is defined as the total magmatic pressure in the dike minus the minimum principal compressive (maximum tensile) stress s 3 acting on the dike walls. Many have estimated the magma overpressure based on dike thickness (or aperture for a magma-filled dike fracture) and the assumption that the host rock behaves as elastic [e.g., Delaney and Pollard, 1981;Pollard et al, 1983;Pollard and Segall, 1987]. In such studies, the following fundamental equation [e.g., Sneddon and Lowengrub, 1969] is used:…”

Section: Introductionmentioning

confidence: 99%

Aspect ratios and magma overpressures of non‐feeder dikes observed in the Miyake‐jima volcano (Japan), and fracture toughness of its upper part

Kusumoto

Geshi

Guðmundsson

2013

Geophysical Research Letters

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[1] We present a new method for estimating the length and maximum thickness (aperture) of a dike from the observed opening at one dike tip. We apply the method to 15 arrested non-feeder dikes (where the upper tip is known, the lower tip unknown) in the caldera walls of Miyake-jima, Japan, to estimate the length-thickness ratio, as well as the magma overpressure and fracture toughness. The calculated length-thickness ratio ranges from 61 to 246, with an average of 136. The ratios are low because the dikes are emplaced close to the surface in comparatively compliant (soft) rocks. Using these ratios and the appropriate elastic constants, the calculated magmatic overpressures of the dikes are between 2.3 and 8.9 MPa, and the stress intensity factors between 38 and 117 MPa m 1/2 . All these values are within the range of typical in situ estimates, supporting the validity of this new method. Citation: Kusumoto S., N.Geshi, and A. Gudmundsson (2013), Aspect ratios and magma overpressures of non-feeder dikes observed in the Miyake-jima volcano (Japan), and fracture toughness of its upper part,

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Surface Deformation in Volcanic Rift Zones

Cited by 76 publications

References 20 publications

Topographic controls on dike injection in volcanic rift zones

Topographic controls on dike injection in volcanic rift zones

Giant Dike Swarms: Earth, Venus, and Mars

Aspect ratios and magma overpressures of non‐feeder dikes observed in the Miyake‐jima volcano (Japan), and fracture toughness of its upper part

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