Annabelle Foster

Caldera faults can be sintered volcanic conduits without necessarily requiring catastrophic rapid slip events

Frankie L. Haywood, Fabian Ben Wadsworth, Madeleine C. S. Humphreys, Dave McGarvie et autres

Caldera subsidence is accommodated by the eruption of large volumes of fragmented magma removed from the crust, commonly transported along caldera ring-faults or between foundering crustal blocks. The largest types of silicic caldera-forming eruptions have not been witnessed, and so the fragmental …

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Magma in the microwave

Fabian Ben Wadsworth, Tamara Carley, Edward W. Llewellin, Annabelle Foster et autres

Classroom demonstrations of volcanic processes are typically performed with low-temperature materials designed to exhibit behaviors conceptually analogous to magma. However, there are advantages to finding methods by which real magma can be created and used with audiences and students. Here, we describe …

Projectile motion: experimental datasets and classroom exercises

Fabian Ben Wadsworth, Jérémie Vasseur, Annabelle Foster, Nathan A Byatt et autres

Abstract The motion of a projectile is a classic topic and is used to illustrate physical and mathematical concepts and techniques. Despite the ubiquity of this problem in pedagogic contexts, there exist few available laboratory datasets and step-by-step exercises for how to …

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Sintering dynamics of fine-grained rhyolitic obsidian particles from Hrafntinnuhryggur (Krafla, Iceland) with implications for silicic volcanic eruptions

Annabelle Foster, Fabian Ben Wadsworth, Jérémie Vasseur, Madeleine C. S. Humphreys et autres

Sintering – or welding – is a key process in volcanic eruptions and controls the formation of welded ignimbrites, obsidian pyroclasts in volcanic conduits, and possibly also silicic lavas. Here, we study the sintering behaviour of packs of fine-grained particles of rhyolitic …

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The viscous-brittle transition in flowing crystal-bearing volcanic dome lavas

Fabian Ben Wadsworth, Jérémie Vasseur, Michael John Heap, Jackie E. Kendrick et autres

The ascent and advance of volcanic dome lava is non-linear and viscoelastic. There exists a mismatch between current theoretical approaches to dome lava rheology, which are based on rheological laws for viscous suspensions, and empirical experimental approaches to convolved viscous-brittle deformation, which …

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The rheology of rhyolite magma from the IDDP-1 borehole and Hrafntinnuhryggur (Krafla, Iceland) with implications for geothermal drilling

Fabian Ben Wadsworth, Jérémie Vasseur, Yan Lavallée, Kai‐Uwe Hess et autres

Changes in rhyolite melt viscosity during magma decompression and degassing exert a first order control on ascent through the crust and volcanic eruption style. These changes have as yet unknown hazard implications for geothermal drilling in pursuit of particularly hot fluids close …

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Evidence for the formation of silicic lava by pyroclast sintering

Annabelle Foster, Fabian Ben Wadsworth, Hugh Tuffen, Holly E. Unwin et autres

Abstract Silicic lavas can be produced by the sintering of pyroclasts in the volcanic sub-surface, and then advected out of the vent. Here, we provide evidence for this mechanism preserved in the exposed post-glacial remnants of a silicic volcanic conduit at Hrafntinnuhryggur, …

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The exposed Mule Creek vent deposits record the structure of a volcanic conduit during a hybrid explosive–effusive eruption

Holly E. Unwin, Hugh Tuffen, Fabian Ben Wadsworth, Emrys R. Phillips et autres

Abstract Silicic volcanic eruptions commonly begin with the explosive ejection of pyroclastic material, before transitioning to gentler effusion-dominated activity. Well-exposed dissected silicic systems are scarce and poorly studied, hindering the advances in our understanding of the explosive–effusive transition needed to improve interpretations …

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A reappraisal of explosive–effusive silicic eruption dynamics: syn-eruptive assembly of lava from the products of cryptic fragmentation

Fabian Ben Wadsworth, Edward W. Llewellin, Jonathan M. Castro, Hugh Tuffen et autres

Silicic volcanic eruptions range in style from gently effusive to highly explosive, and may switch style unpredictably during a single eruption. Direct observations of subaerial rhyolitic eruptions (Chaiten 2008, Cordón Caulle 2011–2012, Chile) challenged long-standing paradigms of explosive and effusive eruptive styles …

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Using obsidian in glass art practice

Fabian Ben Wadsworth, Edward W. Llewellin, Colin Rennie, Cate Watkinson et autres

Glass art practice is indivisible from the material behaviour of glass at a range of working conditions, providing a direct link with the science of glass and melts. The use of non-standard, non-commercial, or natural glass compositions in art usually brings with …

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An Insight into the Origin of Fluidal ObsidianPyroclasts from a Basaltic Fissure Eruption, AscensionIsland, South Atlantic

Annabelle Foster

Basaltic eruptions are the most common manifestations of volcanism on Earth. Pyroclast textures can provide insight into the nature of fragmentation, storage and ascent of magma. Progressing our understanding of eruption dynamics by investigating textural, eld and geochemical data of pyroclasts will …