Remarkable cyclic ground deformation monitored in real‐time on Montserrat, and its use in eruption forecasting

Voight, B.; Hoblitt, Richard P.; Clarke, A. B.; Lockhart, Andrew B.; Miller, Angus D.; Lynch, Lloyd; McMahon, Jay W.

doi:10.1029/98gl01160

Cited by 178 publications

(134 citation statements)

References 5 publications

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“…[36] A clear correlation between tilt and seismicity has been well documented at Montserrat [Voight et al, 1998], where different portions of the tilt cycles correlated with increased levels of seismicity. As noted by Iverson et al [2006], the 2004-2008 eruption of Mount St. Helens also offers an exceptional opportunity to link shallow volcanic seismicity with extrusion dynamics.…”

Section: Association With Seismicitymentioning

confidence: 99%

“…At Montserrat, for example, tilt deflations were correlated with increased rockfall activity, suggesting episodic spine extrusion during these times [Voight et al, 1998]. …”

Section: Continuous Versus Episodic Extrusionmentioning

confidence: 99%

“…Examples include Mount St. Helens in the 1980s, where tiltmeters were used to predict effusive eruptions [Dzurisin et al, 1983], and Soufriere Hills Volcano (Montserrat), where tiltmeters revealed remarkable cyclic eruptive activity correlated with seismicity, gas emissions, explosions, and pyroclastic flows [Voight et al, 1998;Watson et al, 2000] and helped place constraints on source processes and boundary conditions on the conduit walls [Green et al, 2006;Widiwijayanti et al, 2005;Voight et al, 1999;Lensky et al, 2008]. Cyclic or repeating behavior on a variety of timescales has also been observed with different types of instruments during other silicic eruptions including Mount St. Helens during the 2004-2008 eruption [Iverson et al, 2006], Pinatubo [Mori et al, 1996], Santiaguito [Bluth and Rose, 2004], and Unzen [Nakada et al, 1999].…”

Section: Introductionmentioning

confidence: 99%

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Cyclic ground tilt associated with the 2004–2008 eruption of Mount St. Helens

2010

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[1] The long-term behavior of the 2004-2008 effusive eruption of Mount St. Helens was characterized by a gradual decline in the rates of seismicity, dome growth, and broad-scale ground deformation, but shallow near-periodic "drumbeat" earthquakes over timescales of minutes indicated episodic short-term behavior. In part to better characterize this behavior and any associated ground deformation, a network of tiltmeters was installed and recorded thousands of cyclic tilt events within the crater. The duration of these events, from minutes to hours, was too long for them to be directly caused by the drumbeat seismicity. Tilt events were characterized by a recoverable, asymmetric pattern of rapid tilt away from the vent followed by a more gradual reversal, were highly correlated between different tiltmeters in the crater, sometimes occurred in association with volcanic seismicity, and ceased at the end of the eruption. Tilt vectors converged on a point just south of the center of the preexisting 1980s lava dome, and the absence of detectable tilt outside the crater suggests a shallow source (<1 km). We examine several models, including cycles of conduit pressurization and plug slip or gas loss and stick-slip behavior on the interface between the ascending plug and the 1980s lava dome. The small number of stations within the crater prevents a unique determination of source type or geometry, but results are consistent with a mechanism involving extrusion of the semisolid dacite plug and/or cycles of conduit pressurization.

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Section: Association With Seismicitymentioning

confidence: 99%

“…At Montserrat, for example, tilt deflations were correlated with increased rockfall activity, suggesting episodic spine extrusion during these times [Voight et al, 1998]. …”

Section: Continuous Versus Episodic Extrusionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Cyclic ground tilt associated with the 2004–2008 eruption of Mount St. Helens

2010

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“…The reference state is the Poiseuille flow with a constant viscosity. The blue boxes indicate the tilt amplitude recorded in two andesitic volcanoes: boxes 1 and 2 at Soufrière Hills (Montserrat) in May-August 1997 and December 1996, respectively [Voight et al, 1998], and box 3 at Mt. St. Helens between July 2006 and January 2007 [Anderson et al, 2010].…”

Section: Origin Of Cyclic Deformationmentioning

confidence: 99%

“…[43] At Soufrière Hills Volcano (Montserrat), tilt cycles were recorded at 600-700 m from the crater vent, first in December 1996 with an amplitude of 1-2 mrad and a period of 6-8 h, and few months after, from April to May 1997, with an amplitude between 10 and 25 mrad and a period of 12-18 h [Voight et al, 1998]. The cyclic behavior of the surface deformation, with a deflation phase more rapid than the inflation one, is also correlated with cycles in seismic activity and gas emissions of SO 2 [Watson et al, 2000].…”

Section: Influence Of Viscosity Profilementioning

confidence: 99%

Conditions for detection of ground deformation induced by conduit flow and evolution

et al. 2011

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[1] At mature andesitic volcanoes, magma can reach the surface through the same path for several eruptions thus forming a volcanic conduit. Because of degassing, cooling, and crystallization, magma viscosity increase in the upper part of the conduit may induce the formation of a viscous plug. We conducted numerical simulations to quantify the deformation field caused by this plug emplacement and evolution. Stress continuity between Newtonian magma flow and elastic crust is considered. Plug emplacement causes a ground inflation correlated to a decrease of the magma discharge rate. A parametric study shows that surface displacements depend on three dimensionless numbers: the conduit aspect ratio (radius/length), the length ratio between the plug and the conduit, and the viscosity contrast between the plug and the magma column. Larger displacements are obtained for high-viscosity plugs emplaced in large aspect ratio conduits. We find that only tiltmeters or GPS located close to the vent (a few hundred meters) might record the plug emplacement. At immediate proximity of the vent, plug emplacement might even dominate the deformation signal over dome growth or magma reservoir pressurization effects. For given plug thicknesses and viscosity profiles, our model explains well the amplitude of tilt variations (from 1 to 25 mrad) measured at Montserrat and Mt. St. Helens. We also demonstrate that at Montserrat, even if most of the tilt signal is due to shear stress induced by magma flow, pressurization beneath the plug accounts for 20% of the signal.

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Seismological analysis of conduit dynamics in fragmentation experiments

Arciniega-Ceballos¹,

Alatorre‐Ibargüengoitia

Scheu

et al. 2014

JGR Solid Earth

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We simulate gas-burst and volcanic explosions under controlled laboratory conditions inducing fragmentation of volcanic rocks by rapid depressurization. A series of experiments were performed in a shocktube apparatus at room temperature and a pressure range of 4 to 20 MPa using Argon (Ar) gas and, particles or pumice samples of different porosities. The instrumentation of this system with high-precision piezoelectric sensors enabled us to capture elastic waves and to recognize their characteristic signatures. By relating these signals to physical processes in the wave field, we have been able to characterize the conduit mechanism and the source dynamics. We compare and discuss conspicuous features of the waveforms and frequency spectra of these experimental signals with those of volcanic origin. Despite the fact that these signals are different in amplitude (resulting from different scale conditions); our observations indicate that the physical processes that occur during simulated explosions and those that occur during volcanic eruptions yield comparable signatures in their respective records. The effects of the source-receiver configuration and resonance also have significant implications. All this suggests that the physical processes (e.g. pressurization and depressurization of a system) involve a system response that causes similar distinctive effects independent of the system size, reflecting its intrinsic dynamics. These similarities imply that powerful constraints on the source mechanisms of volcanic seismicity can emerge from seismic investigations of experimental simulations of volumetric sources. Such constraints may yield significant advances in the understanding of volcanic conduit dynamics and in the interpretation of seismic unrest at volcanic centers.

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Remarkable cyclic ground deformation monitored in real‐time on Montserrat, and its use in eruption forecasting

Cited by 178 publications

References 5 publications

Cyclic ground tilt associated with the 2004–2008 eruption of Mount St. Helens

Cyclic ground tilt associated with the 2004–2008 eruption of Mount St. Helens

Conditions for detection of ground deformation induced by conduit flow and evolution

Seismological analysis of conduit dynamics in fragmentation experiments

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