Preprints
Filtering by Subject: Volcanology
The hazards of unconfined pyroclastic density currents: a new synthesis and classification according to their deposits, dynamics, and thermal and impact characteristics
Published: 2021-06-08
Subjects: Earth Sciences, Physical Sciences and Mathematics, Volcanology
Pyroclastic density currents (PDCs) that escape their confining channels are among the most dangerous of volcanic hazards. These unconfined PDCs are capable of inundating inhabited areas that may be unprepared for these hazards, resulting in significant loss of life and damage to infrastructure. Despite their ability to cause serious impacts, unconfined PDCs have previously only been described [...]
Quantifying the influence of conduit inclination on Taylor Bubble behaviour in basaltic magmas.
Published: 2021-05-27
Subjects: Earth Sciences, Physical Sciences and Mathematics, Volcanology
The ascent of single Taylor bubbles suspended in a range of Newtonian liquids, scaled to mimic basaltic magmas, within vertical and inclined tubes has been studied experimentally over the range 0° to 70° (where 0° is vertical and 90° is horizontal). Using measurements of Taylor bubble parameters (ascent velocity and film thickness) and morphology, alongside dimensionless numbers, we show that [...]
A radial hydraulic fracture driven by a Herschel–Bulkley fluid
Published: 2021-05-27
Subjects: Fluid Dynamics, Hydraulic Engineering, Hydrology, Numerical Analysis and Scientific Computing, Oil, Gas, and Energy, Volcanology
We analyse the influence of fluid yield stress on propagation of a radial (penny-shaped) hydraulic fracture in a permeable reservoir. In particular, the Herschel-Bulkley rheological model is adopted that includes yield stress and non-linearity of the shear stress. The rock is assumed to be linear elastic, and the fracture is driven by the point source fluid injection with a constant volumetric [...]
AMS and rock magnetism in the Caviahue-Copahue Volcanic Complex (Southern Andes): emission center, flow dynamics, and implications to the emplacement of non-welded PDCs
Published: 2021-05-14
Subjects: Earth Sciences, Geology, Geophysics and Seismology, Physical Sciences and Mathematics, Volcanology
Pyroclastic deposits can cover significant areas and register major geological events. Despite their importance, understanding depositional dynamics of pyroclastic density currents (PDCs) and linking explosive deposits to their emission centers is still a challenge, especially in the case of non-welded, massive ignimbrites. Located in the Southern Andes, the Caviahue Copahue Volcanic Complex [...]
Insights into the nature of plume-ridge interaction and outflux of H2O from the Galápagos Spreading Centre
Published: 2021-02-18
Subjects: Earth Sciences, Geochemistry, Other Earth Sciences, Physical Sciences and Mathematics, Volcanology
The flow of high-temperature and compositionally-enriched material between mantle plumes and nearby spreading centres influences up to 30% of the global mid-ocean ridge system and represents a significant, but currently unconstrained, flux of volatiles out of the mantle. Here we present new analyses of H2O, F, Cl and S in basaltic glass chips from an archetypal region of plume-ridge interaction, [...]
Classification, segmentation and correlation of zoned minerals
Published: 2021-02-01
Subjects: Earth Sciences, Environmental Sciences, Geochemistry, Geology, Numerical Analysis and Scientific Computing, Statistics and Probability, Volcanology
Minerals exhibit zoning patterns that can be related to changes in the environment in which they grew. Using statistical methods that have been designed to segment optical images, we have developed a procedure to segment zonation within minerals and correlate these zones between multiple crystals using elemental maps. This allows us to quantify the complexity and variability of chemical zoning [...]
Quantitative chemical mapping of plagioclase as a tool for the interpretation of volcanic stratigraphy: an example from Saint Kitts, Lesser Antilles
Published: 2021-02-01
Subjects: Earth Sciences, Geochemistry, Geology, Stratigraphy, Volcanology
Establishing a quantitative link between magmatic processes occurring at depth and volcanic eruption dynamics is essential to forecast the future behaviour of volcanoes, and to correctly interpret monitoring signals at active centres. Chemical zoning in minerals, which captures successive events or states within a magmatic system, can be exploited for such a purpose. However, to develop a [...]
Observational estimates of dynamic topography through space and time
Published: 2021-01-24
Subjects: Biogeochemistry, Cosmochemistry, Earth Sciences, Geochemistry, Geology, Geomorphology, Geophysics and Seismology, Paleobiology, Physical Sciences and Mathematics, Sedimentology, Stratigraphy, Tectonics and Structure, Volcanology
Earth's mantle undergoes convection on million-year timescales as heat is transferred from depth to the surface. Whilst this flow has long been linked to the large-scale horizontal forces that drive plate tectonics and supercontinent cycles, geologists are increasingly recognising the signature of convection through transient vertical motions in the rock record, known as "dynamic topography". A [...]
The building blocks of igneous sheet intrusions: insights from 3D seismic reflection data
Published: 2021-01-19
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Tectonics and Structure, Volcanology
The propagating margins of igneous sills (and other sheet intrusions) may divide into laterally and/or vertically separated sections, which later inflate and coalesce. These components elongate parallel to and thus record the magma flow direction, and can form either due to fracture segmentation (i.e., ‘segments’) or brittle and/or non-brittle deformation of the host rock (i.e., ‘magma fingers’). [...]
Integrated magnetotelluric and petrological analysis of felsic magma reservoirs: Insights from Ethiopian rift volcanoes
Published: 2021-01-16
Subjects: Earth Sciences, Geochemistry, Geophysics and Seismology, Volcanology
Geophysical and petrological probes are key to understanding the structure and the thermochemical state of active magmatic systems. Recent advances in laboratory analyses, field investigations and numerical methods have allowed increasingly complex data-constraint models with new insights into magma plumbing systems and melt evolution. However, there is still a need for methods to quantitatively [...]
Simultaneous classification and location of volcanic deformation in SAR interferograms using a convolutional neural network
Published: 2021-01-12
Subjects: Volcanology
With the evolution of InSAR into a tool for active hazard monitoring, new methods are sought to quickly and automatically interpret the large number of interferograms that are created. We present a convolutional neural network (CNN) that is able to both classify the type of deformation, and to locate the deformation within an interferogram in a single step. We achieve this through building a “two [...]
Structural controls on the emplacement and evacuation of magma from a sub-volcanic laccolith; Reyðarártindur Laccolith, SE Iceland
Published: 2021-01-06
Subjects: Earth Sciences, Geology, Higher Education, Physical Sciences and Mathematics, Science and Mathematics Education, Tectonics and Structure, Volcanology
VESIcal Part I: An open-source thermodynamic model engine for mixed volatile (H2O-CO2) solubility in silicate melts
Published: 2020-12-08
Subjects: Earth Sciences, Geochemistry, Geology, Physical Sciences and Mathematics, Planetary Geochemistry, Planetary Geology, Planetary Sciences, Volcanology
Thermodynamics has been fundamental to the interpretation of geologic data and modeling of geologic systems for decades. However, more recent advancements in computational capabilities and a marked increase in researchers’ accessibility to computing tools has outpaced the functionality and extensibility of currently available modeling tools. Here we present VESIcal (Volatile Equilibria and [...]
The shape of volcanic conduits inferred from bubble size distributions
Published: 2020-11-28
Subjects: Earth Sciences, Volcanology
The most intense known explosive volcanic eruptions on Earth are Plinian eruptions of silicic magma. Geospeedometers indicate that Plinian magma erupts from high pressure within the magma chamber at average speeds of 0.001-1 MPa/s. Concurrently dissolved magmatic volatiles, predominantly water, nucleate about one quadrillion bubbles per cubic meter of melt, preserved as vesicles within tephra. [...]
Boron isotopic signatures of melt inclusions from North Iceland reveal recycled material in the Icelandic mantle source
Published: 2020-11-13
Subjects: Earth Sciences, Geochemistry, Geology, Physical Sciences and Mathematics, Volcanology
Trace element and volatile heterogeneity in the Earth's mantle is in uenced by the recycling of oceanic lithosphere through subduction. Oceanic island basalts commonly have high concentrations of volatiles compared to mid-ocean ridge basalts, but the extent to which this enrichment is linked to recycled mantle domains remains unclear. Boron is an ideal tracer of recycled subducted material, [...]