Volcano geodesy: The search for magma reservoirs and the formation of eruptive vents

Dvorak, John J.; Dzurisin, Daniel

doi:10.1029/97rg00070

Cited by 276 publications

(183 citation statements)

References 200 publications

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“…This compares to an estimate of 10 million m 3 for the total volume output (solid rock equivalent) estimated from ash mapping [Pallister et al, 2005;Trusdell et al, 2005]. For most eruptions, the injection volume is less than the total volcanic output [e.g., Dvorak and Dzurisin, 1997], so this calculation shows that the observed tilt obtained from the STS-2 seismograph is compatible with other estimates of the volume of the Anatahan eruption.…”

Section: Tilt Magnitude and Source Volumesupporting

confidence: 73%

Tilt recorded by a portable broadband seismograph: The 2003 eruption of Anatahan Volcano, Mariana Islands

Wiens

Pozgay

Shore

et al. 2005

Geophysical Research Letters

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The horizontal components of broadband seismographs are highly sensitive to tilt, suggesting that commonly deployed portable broadband seismic sensors may record important tilt information associated with volcanic eruptions. We report on a tilt episode that coincides with the first historical eruption of Anatahan volcano on May 10, 2003. The tilt was recorded by a Strekheisen STS‐2 seismograph deployed in an underground insulated chamber 7 km west of the active vent. An ultra‐long period signal with a dominant period of several hours was recorded on the E‐W component beginning at 06:20 GMT on May 10, which coincides with the onset of continuous volcano‐tectonic (VT) seismicity and is one hour prior to the eruption time estimated by the Volcanic Ash Advisory Center. The signal is much smaller on the N‐S component and absent on the vertical component, suggesting it results from tilt that is approximately radial with respect to the active vent. An estimate of tilt as a function of time is recovered by deconvolving the record to acceleration and dividing by the acceleration of gravity. The record indicates an initial episode of tilt downward away from the volcanic center from 06:20–09:30 GMT, which we interpret as inflation of the shallow volcanic source. The tilt reverses, recording deflation, from 09:30 until 17:50, after which the tilt signal becomes insignificant. The inflation corresponds to a period of numerous VT events, whereas fewer events were recorded during the deflation episode, and the VT events subsequently resumed after the end of the deflationary tilt. The maximum tilt of 2 microradians can be used to estimate the volume of the source inflation (∼2 million m3), assuming a simple Mogi source model. These calculations are consistent with other estimates of source volume if reasonable source depths are assumed. Examination of broadband records of other eruptions may disclose further previously unrecognized tilt signals.

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Section: Tilt Magnitude and Source Volumesupporting

confidence: 73%

Tilt recorded by a portable broadband seismograph: The 2003 eruption of Anatahan Volcano, Mariana Islands

Wiens

Pozgay

Shore

et al. 2005

Geophysical Research Letters

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“…Numerous studies in the Cascades, Tonga and Vanuatu have consistently failed to nd any evidence for their existence (see summaries by Gill (1981) and Iyer (1984)). Moreover, when crustal magma chambers have been observed beneath subduction-zone andesite volcanoes, they tend to be small (10 3 m in diameter) and shallow (typically 1{3 km in depth) and, by implication, transitory features (Iyer 1984;Marsh 1989;Dvorak & Dzurisin 1997). Thus, Gill (1981) concluded that if magma chambers exist, they are beneath dacitic to rhyolitic volcanoes.…”

Section: Residence Times Within the Crustmentioning

confidence: 99%

Time-scales of magma formation, ascent and storage beneath subduction-zone volcanoes

Turner

George

Evans

et al. 2000

Philosophical Transactions of the Royal Society of London. Seri

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There is now su¯cient information to attempt an integrated model for melt generation, transfer and storage beneath subduction-zone volcanoes. Fluid release from the subducting oceanic crust into the mantle wedge may occur over a period ranging from a few hundred kyr, to as little as less than 1 kyr, before eruption. This supports models in which ®uid addition is closely linked to partial melting, though there may also be evidence for a component of decompression melting. The timing of the onset of ®uid addition may be linked to the rate of subduction (i.e. water supply rate) and the angle of subduction, and, consequently, the thermal structure of the mantle wedge. In contrast, contributions from subducted sediments to subduction-zone lava sources appear to occur some 350 kyr{4 Myr before eruption. Evidence for partial melting of the sediment component, combined with the short ®uid transfer times, phenocryst equilibration temperatures and other observations all point to quite high mantle wedge temperatures close to the interface with the subducting plate. New 226 Ra data permit only a short period of time between ®uid addition and eruption. This requires rapid melt segregation, magma ascent by channelled ®ow and minimal residence time within the lithosphere. Typically, the evolution from basalt to andesite occurs rapidly during ascent or in magma reservoirs, inferred from some geophysical data to lie within the lithospheric mantle. Mineral isochron data suggest that some andesitic magmas subsequently stall in more shallow crustal level magma chambers, where they can evolve to dacitic compositions via fractionation, typically combined with assimilation, on time-scales of a few thousand years or less.

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“…[2] Measured ground surface displacement (GSD) rates in calderas span several orders of magnitude, from mm a À1 (detection limit) to m a À1 , over periods of observation that range from subannual to millennial [e.g., Dvorak and Dzurisin, 1997;Dzurisin, 2003Dzurisin, , 2007Poland et al, 2006]. Modern geodetic techniques such as interferometric synthetic aperture radar (InSAR) and GPS provide unprecedented insight into the temporal and spatial evolution of GSD, and reveal that deformation patterns can be highly variable both in space and in time [e.g., Battaglia and Segall, 2004;Chang et al, 2007;Kwoun et al, 2006;Wicks et al, 2006].…”

Section: Introductionmentioning

confidence: 99%

Numerical models of caldera deformation: Effects of multiphase and multicomponent hydrothermal fluid flow

et al. 2009

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[1] Ground surface displacement (GSD) in large calderas is often interpreted as resulting from magma intrusion at depth. Recent advances in geodetic measurements of GSD, notably interferometric synthetic aperture radar, reveal complex and multifaceted deformation patterns that often require complex source models to explain the observed GSD. Although hydrothermal fluids have been discussed as a possible deformation agent, very few quantitative studies addressing the effects of multiphase flow on crustal mechanics have been attempted. Recent increases in the power and availability of computing resources allow robust quantitative assessment of the complex time-variant thermal interplay between aqueous fluid flow and crustal deformation. We carry out numerical simulations of multiphase (liquid-gas), multicomponent (H 2 O-CO 2 ) hydrothermal fluid flow and poroelastic deformation using a range of realistic physical parameters and processes. Hydrothermal fluid injection, circulation, and gas formation can generate complex, temporally and spatially varying patterns of GSD, with deformation rates, magnitudes, and geometries (including subsidence) similar to those observed in several large calderas. The potential for both rapid and gradual deformation resulting from magma-derived fluids suggests that hydrothermal fluid circulation may help explain deformation episodes at calderas that have not culminated in magmatic eruption.

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Volcano geodesy: The search for magma reservoirs and the formation of eruptive vents

Cited by 276 publications

References 200 publications

Tilt recorded by a portable broadband seismograph: The 2003 eruption of Anatahan Volcano, Mariana Islands

Tilt recorded by a portable broadband seismograph: The 2003 eruption of Anatahan Volcano, Mariana Islands

Time-scales of magma formation, ascent and storage beneath subduction-zone volcanoes

Numerical models of caldera deformation: Effects of multiphase and multicomponent hydrothermal fluid flow

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