Experimental constraints on pre-eruptive water contents and changing magma storage prior to explosive eruptions of Mount St Helens volcano

Gardner, James E.; Rutherford, M. J.; Carey, Steven; Sigurdsson, Haraldur

doi:10.1007/bf00298703

Cited by 173 publications

(55 citation statements)

References 33 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Phase assemblages and compositions of rocks erupted from MSH over the last 4000 years indicate a wide range of water concentrations, from 3.7 to 6.5 wt% [Rutherford and Devine, 1988;Gardner et al, 1995]. Few melt inclusions are available for the [2004][2005][2006][2007][2008] eruption, but modeling by Gerlach et al [2008] beginning with a total water concentration of 5 wt% at 220 MPa suggests a dissolved water concentration at the top of the chamber of around 4.4 wt% (along with a total CO 2 concentration of approximately 2000 ppm).…”

Section: Results For Mount St Helensmentioning

confidence: 99%

Bayesian inversion of data from effusive volcanic eruptions using physics‐based models: Application to Mount St. Helens 2004–2008

2013

View full text Add to dashboard Cite

[1] Physics-based models of volcanic eruptions can directly link magmatic processes with diverse, time-varying geophysical observations, and when used in an inverse procedure make it possible to bring all available information to bear on estimating properties of the volcanic system. We develop a technique for inverting geodetic, extrusive flux, and other types of data using a physics-based model of an effusive silicic volcanic eruption to estimate the geometry, pressure, depth, and volatile content of a magma chamber, and properties of the conduit linking the chamber to the surface. A Bayesian inverse formulation makes it possible to easily incorporate independent information into the inversion, such as petrologic estimates of melt water content, and yields probabilistic estimates for model parameters and other properties of the volcano. Probability distributions are sampled using a Markov-Chain Monte Carlo algorithm. We apply the technique using GPS and extrusion data from the 2004-2008 eruption of Mount St. Helens. In contrast to more traditional inversions such as those involving geodetic data alone in combination with kinematic forward models, this technique is able to provide constraint on properties of the magma, including its volatile content, and on the absolute volume and pressure of the magma chamber. Results suggest a large chamber of >40 km 3 with a centroid depth of 11-18 km and a dissolved water content at the top of the chamber of 2.6-4.9 wt%.

show abstract

Section: Results For Mount St Helensmentioning

confidence: 99%

Bayesian inversion of data from effusive volcanic eruptions using physics‐based models: Application to Mount St. Helens 2004–2008

2013

View full text Add to dashboard Cite

show abstract

“…Some of the important results provided by these lines of research are assessment of preeruptive conditions in the magma chamber ( Johnson at al. 1994;Gardner at al. 1995;Rutherford and Devine 1996;Rutherford et al 1998), determination of volatile solubility and diffusion (see Zhang 1999 for a review) and magma viscosity (Hess and Dingwell 1996;Giordano and Dingwell 2003) along the volcanic conduit for a range of compositions, identification of processes as degassinginduced crystallization (Hammer et al 1999), magma permeability (Klug and Cashman 1996), shear and crystal fragmentation at conduit walls (Polacci et al 2001), numerical modeling development of magma ascent and fragmentation Papale 1999;Melnik 2000), and pyroclast dispersal in the atmosphere (Neri et al , 2002.…”

Section: Introductionmentioning

confidence: 92%

Role of conduit shear on ascent of the crystal-rich magma feeding the 800-year-b.p. Plinian eruption of Quilotoa Volcano (Ecuador)

Rosi

Landi²,

Polacci

et al. 2004

Bulletin of Volcanology

View full text Add to dashboard Cite

Role of conduit shear on ascent of the crystal-rich magma feeding the 800-year-b.p. Plinian eruption of Quilotoa Volcano (Ecuador) Abstract We have characterized pumice products belonging to the climactic phase of the 800-year-b.p. Quilotoa eruption. Bulk rock compositions, petrography, mineral, and glass chemistry and textural investigations were performed on the three end-member pumice types, namely white, gray, and mingled pumices. All the investigated pumice clasts are dacites characterized by the same bulk rock composition and mineralogical assemblage, but glass compositions and bulk textures change according to different pumice types. White pumice has higher crystallinity (~48 wt%), abundant euhedral pheno/microphenocrysts, no groundmass microlites, the most evolved glass compositions (74-78 wt% SiO 2 ), and heterogeneous vesicle populations marked by deformed and highly coalesced vesicles with thin walls. Gray pumice exhibits lower crystallinity (29-36 wt%), abundant broken and/or resorbed crystals, ubiquitous groundmass phenocryst fragments and microlites, the widest range of glass compositions (69-78 wt% SiO 2 ), and quite homogeneous poorly deformed and coalesced vesicles with thicker walls. Mingled pumices are characterized by the alternation of bands or patches with white and gray pumice compositional and textural characteristics. We attribute heterogeneities in glass compositions and crystal and vesicle textures to processes occurring within volcanic conduits as magma is ascending to the surface. In particular, the above observations and results are consistent with an origin of a gray magma by heating of the original white magma in a strongly sheared region of the conduit because of a mechanism of viscous dissipation and crystal grinding and resorption at the conduit walls. The less viscous gray magma, therefore, would enable the onset and preservation of a high mass flux of the eruption otherwise difficult to explain for highly viscous crystal-rich dacitic magmas.

show abstract

“…The preeruptive meltwater content can be inferred by comparing the petrological characteristics of experimental products (phenocryst assemblages, phenocryst modes, anhydrous groundmass compositions, phenocryst compositions, and temperatures) with those of the erupted magmas [e.g., Gardner et al, 1995;Scaillet and Evans, 1999]. Instead of undertaking experiments for individual examples, thermodynamic models that are based on large amounts of experimental data can be used to constrain preeruptive meltwater contents.…”

Section: A21 Phase Equilibrium Relationsmentioning

confidence: 99%

Preeruptive magma viscosity: An important measure of magma eruptibility

Takeuchi

2011

J. Geophys. Res.

View full text Add to dashboard Cite

[1] Using a compilation of melt compositions, meltwater contents, temperatures, and phenocryst contents, the preeruptive viscosities under magma reservoir conditions are calculated for 83 erupted magmas. The basaltic-to-rhyolitic magmas have preeruptive viscosities over the range 10 1 to 10 8 Pa s. Although bulk SiO 2 content has often been used as a qualitative measure of preeruptive magma viscosity, the bulk SiO 2 content shows a weak correlation with magma viscosity (correlation coefficient r = 0.5). Because of a wide range of phenocryst contents from 0 to ∼50 vol %, andesitic magmas have viscosities ranging from 10 2 to 10 7 Pa s, which are lower or higher than those of phenocryst-poor rhyolitic magmas with 10 5 to 10 6 Pa s. Focusing on andesitic to rhyolitic magmas, the r between bulk SiO 2 contents and magma viscosities changes to −0.1. In contrast, the melt-only SiO 2 content from a basaltic-to-rhyolitic melt shows a good linear correlation with melt-only viscosity (r = 0.9). Although most of the calculated viscosities of erupted magmas fall below ∼106 Pa s, as consistent with the previous compilation study, this paper describes 20 examples of highly viscous magmas with >106 Pa s, in most cases, composed of mixtures of high-silica rhyolitic melt (75-79 wt % SiO 2 ) and abundant phenocrysts (30-55 vol %). In these highly viscous magmas, 9 examples have erupted following the precursory eruption of less viscous magma, suggesting that precursory dike propagation and conduit formation by the less viscous magma with <10 6 Pa s induced the following eruption of less eruptible, highly viscous magmas.

show abstract

Experimental constraints on pre-eruptive water contents and changing magma storage prior to explosive eruptions of Mount St Helens volcano

Cited by 173 publications

References 33 publications

Bayesian inversion of data from effusive volcanic eruptions using physics‐based models: Application to Mount St. Helens 2004–2008

Bayesian inversion of data from effusive volcanic eruptions using physics‐based models: Application to Mount St. Helens 2004–2008

Role of conduit shear on ascent of the crystal-rich magma feeding the 800-year-b.p. Plinian eruption of Quilotoa Volcano (Ecuador)

Preeruptive magma viscosity: An important measure of magma eruptibility

Contact Info

Product

Resources

About