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Quantifying the Sedimentation of Ignimbrites

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Behaviours of pyroclastic and analogue materials, in dry and wet environments, for use in experimental modelling of pyroclastic density currents (2025)
Journal Article
Walding, N., Williams, R., Rowley, P., Dowey, N., Parsons, D., & Bird, A. (2025). Behaviours of pyroclastic and analogue materials, in dry and wet environments, for use in experimental modelling of pyroclastic density currents. Volcanica, 8(1), 261-285. https://doi.org/10.30909/vol/oxkm9163

Modelling pyroclastic density currents (PDCs) is a challenging yet essential element of hazard assessment. PDCs are unpredictable and internal processes are often difficult to measure directly. Analogue experiments have been an important tool for inv... Read More about Behaviours of pyroclastic and analogue materials, in dry and wet environments, for use in experimental modelling of pyroclastic density currents.

The influence of moisture on ash strength: implications for understanding volcanic stratigraphy (2025)
Journal Article
Walding, N., Williams, R., Dowey, N., Rowley, P., Thomas, M., Osman, S., Johnson, M., & Parsons, D. R. (2025). The influence of moisture on ash strength: implications for understanding volcanic stratigraphy. Bulletin of volcanology, 87(6), Article 39. https://doi.org/10.1007/s00445-025-01821-4

Ash layers within extensive pyroclastic density current (PDC) deposits can be important in understanding the evolution of explosive eruptions. If interpreted as ashfall deposits, they may be used to identify hiatus episodes and determine how many pyr... Read More about The influence of moisture on ash strength: implications for understanding volcanic stratigraphy.

Cohesional behaviours in pyroclastic material and the implications for deposit architecture (2023)
Journal Article
Walding, N., Williams, R., Rowley, P., & Dowey, N. (2023). Cohesional behaviours in pyroclastic material and the implications for deposit architecture. Bulletin of volcanology, 85(11), Article 67. https://doi.org/10.1007/s00445-023-01682-9

Pyroclastic density currents (PDCs) are hazardous, multiphase currents of heterogeneous volcanic material and gas. Moisture (as liquid or gas) can enter a PDC through external (e.g., interaction with bodies of water) or internal (e.g., initial erupti... Read More about Cohesional behaviours in pyroclastic material and the implications for deposit architecture.

Anatomy of a volcanic eruption undersea (2023)
Journal Article
Williams, R., & Rowley, P. (2023). Anatomy of a volcanic eruption undersea. Science, 381(6662), 1046-1047. https://doi.org/10.1126/science.adk0181

In December 2021, an undersea volcano in the southern Pacific Ocean, the Hunga Tonga–Hunga Ha‘apai (hereafter called the Hunga volcano) began erupting. In January 2022 the eruption reached a powerful climax, triggering atmospheric waves that traveled... Read More about Anatomy of a volcanic eruption undersea.

Simultaneous fall and flow during pyroclastic eruptions: A novel proximal hybrid facies (2022)
Journal Article
Dowey, N., & Williams, R. (2022). Simultaneous fall and flow during pyroclastic eruptions: A novel proximal hybrid facies. Geology, 50(10), 1187-1191. https://doi.org/10.1130/G50169.1

The deposits of Plinian and subplinian eruptions provide critical insights into past volcanic events and inform numerical models that aim to mitigate against future hazards. However, pyroclastic deposits are often considered from either a fallout or... Read More about Simultaneous fall and flow during pyroclastic eruptions: A novel proximal hybrid facies.

A bedform phase diagram for dense granular currents (2020)
Journal Article
Smith, G., Rowley, P., Williams, R., Giordano, G., Trolese, M., Silleni, A., Parsons, D. R., & Capon, S. (2020). A bedform phase diagram for dense granular currents. Nature communications, 11(1), Article 2873. https://doi.org/10.1038/s41467-020-16657-z

Pyroclastic density currents (PDCs) are a life-threatening volcanic hazard. Our understanding and hazard assessments of these flows rely on interpretations of their deposits. The occurrence of stratified layers, cross-stratification, and bedforms in... Read More about A bedform phase diagram for dense granular currents.

Explosive eruptive history of Pantelleria, Italy : repeated caldera collapse and ignimbrite emplacement at a peralkaline volcano (2017)
Journal Article
Jordan, N., Rotolo, S., Williams, R., Speranza, F., McIntosh, W., Branney, M. J., & Scaillet, S. (2018). Explosive eruptive history of Pantelleria, Italy : repeated caldera collapse and ignimbrite emplacement at a peralkaline volcano. Journal of Volcanology and Geothermal Research, 349, 47-73. https://doi.org/10.1016/j.jvolgeores.2017.09.013

A new, pre-Green Tuff (46 ka) volcanic stratigraphy is presented for the peralkaline Pantelleria Volcano, Italy. New ⁴⁰Ar/³⁹Ar and paleomagnetic data are combined with detailed field studies to develop a comprehensive stratigraphic reconstruction of... Read More about Explosive eruptive history of Pantelleria, Italy : repeated caldera collapse and ignimbrite emplacement at a peralkaline volcano.

Temporal and spatial evolution of a waxing then waning catastrophic density current revealed by chemical mapping (2014)
Journal Article
Williams, R., Branney, M. J., & Barry, T. L. (2014). Temporal and spatial evolution of a waxing then waning catastrophic density current revealed by chemical mapping. Geology, 42(2), 107-110. https://doi.org/10.1130/G34830.1

We reconstruct the behavior of a catastrophic sustained radial pyroclastic density current as it waxed then waned during its brief lifespan. By subdividing the deposit into 8 time slices using a chemical tracer, we show that the sustained current ini... Read More about Temporal and spatial evolution of a waxing then waning catastrophic density current revealed by chemical mapping.