Filtering by Subject: Volcanology

Control of heterogeneous, layered successions on shallow-level magma emplacement and host rock deformation

Craig Magee, Domenico Montanari, Giacomo Corti

Published: 2019-08-07
Subjects: Earth Sciences, Physical Sciences and Mathematics, Volcanology

Host rock deformation in active volcanic settings can signal and be used to constrain magma emplacement. Yet it is difficult to evaluate the accuracy of intrusion parameters derived from inversion of deformation signals because we cannot test estimates by directly accessing the magma body. Physical modelling is thus critical to understanding how intrusion translates into host rock deformation, [...]

Seismological evidence for subcrustal magmatic injection beneath Fogo volcano, Cape Verde hotspot

Carola Leva, Georg Rümpker, Frederik Link, Ingo Wölbern

Published: 2019-07-09
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics, Volcanology

Fogo volcano belongs to the Cape Verde hotspot and its most recent eruption occurred from November 2014 to February 2015. From January to December 2016 we operated a temporary seismic network on Fogo and were able to locate 289 earthquakes in total. While most of the events occur at distances > 25 km near the neighboring island of Brava. However, on 15th August 2016 we recorded an isolated [...]

The Leaning Puy de Dôme

Benjamin van Wyk de Vries, Michael S Petronis, Daniel Garcia

Published: 2019-07-08
Subjects: Earth Sciences, Geomorphology, Physical Sciences and Mathematics, Tectonics and Structure, Volcanology

Acidic lava domes are a special monogenetic volcano type with explosive eruption hazards. Such domes raise questions about the nature of monogenetic volcanism. We study the iconic Puy de Dôme (Chaîne des Puys, Auvergne) that gave its name to dome landforms. It is asymmetric with one side more rugged and steeper than the other. Using mapping and paleomagnetism we find that it was tilted by ~20° [...]

Tectonic stress controls saucer-shaped sill geometry

Richard Walker, Simon Gill

Published: 2019-07-05
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Tectonics and Structure, Volcanology

Saucer-shaped sills are common in sedimentary basins worldwide. The saucer shape relates to asymmetric stress distributions at the sill-tip during intrusion caused by bending of the overburden. Most saucer-shaped sill models are conducted without tectonic stress. Model results are poorly correlated with natural sills in that: (1) modelled saucers are much steeper than natural sills; and (2) [...]

Finite element simulations of sill intrusion during tectonic loading

Richard Walker, Simon Gill

Published: 2019-07-05
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Tectonics and Structure, Volcanology

Igneous sills are common features in tectonically active regions, acting as nascent magma storage systems, or feeding eruptions at large lateral distances from the magma source. Sills reaching a critical radius, rc, relative to their initial depth, H, interact with Earth’s surface, leading to mild discordant growth at angle [theta] typically <10[deg] forming saucer-shaped sills; commonly [...]

A bedform phase diagram for dense granular currents

Gregory Smith, Pete Rowley, Rebecca Williams, Guido Giordano, Matteo Trolese, Aurora Silleni, Daniel R. Parsons, Samuel Capon

Published: 2019-07-04
Subjects: Earth Sciences, Fluid Dynamics, Geology, Physical Sciences and Mathematics, Physics, Sedimentology, Volcanology

Pyroclastic density currents are a life-threatening volcanic hazard. Our understanding and hazard assessments of these flows primarily rely on interpretations of their deposits. The occurrence of stratified layers, cross-stratification, and dune bedforms in these deposits has been assumed as indicative of dilute, turbulent, flows causing traction-dominated deposition. Here we show, through [...]

From prodigious volcanic degassing to caldera subsidence and quiescence at Ambrym (Vanuatu): the influence of regional tectonics

Tara Shreve, Raphaël Grandin, Marie Boichu, Esline Garaebiti, Yves Moussallam, Valérie Ballu, Francisco Delgado, Frédérique Leclerc, Martin Vallée, Nicolas Henriot

Published: 2019-06-28
Subjects: Earth Sciences, Physical Sciences and Mathematics, Tectonics and Structure, Volcanology

Eruptive activity shapes volcanic edifices. The formation of broad caldera depressions is often associated with major collapse events, emplacing conspicuous pyroclastic deposits. However, caldera subsidence may also proceed silently by magma withdrawal at depth, more difficult to detect. Ambrym, a basaltic volcanic island, hosts a 12-km wide caldera and several intensely-degassing lava lakes [...]

Large uncertainty in volcanic aerosol radiative forcing derived from ice cores

Lauren Marshall, Anja Schmidt, Jill Johnson, Graham Mann, Lindsay Lee, Ken Carslaw

Published: 2019-06-20
Subjects: Atmospheric Sciences, Climate, Earth Sciences, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics, Volcanology

Reconstructions of volcanic aerosol radiative forcing are required to understand past climate variability. Currently, reconstructions of pre-20th century volcanic forcing are derived from sulfate concentrations measured in polar ice cores, predominantly using a relationship between average ice sheet sulfate deposition and stratospheric sulfate aerosol based on a single explosive eruption - the [...]

Modification of fumarolic gases by the ice-covered edifice of Erebus volcano, Antarctica

Tehnuka Ilanko, Tobias Fischer, Philip Kyle, Aaron Curtis, Hyunwoo Lee, Yuji Sano

Published: 2019-06-07
Subjects: Earth Sciences, Physical Sciences and Mathematics, Volcanology

The chemistry of gases measured in ice caves and from warm geothermal ground at Erebus volcano, Antarctica, show that gas emissions are dominated by air, with varying amounts of added volcanic CO2. This suggests widespread circulation of air through the volcanic edifice, as well as spatially or temporally varying contributions from magmatic degassing. The resulting gases are further modified by [...]

Physically consistent modeling of dike induced deformation and seismicity: Application to the 2014 Bárðarbunga dike, Iceland

Elias Rafn Heimisson, Paul Segall

Published: 2019-06-03
Subjects: Earth Sciences, Geology, Geophysics and Seismology, Physical Sciences and Mathematics, Volcanology

Dike intrusions are often associated with surface deformation and propagating swarms of earthquakes. These are understood to be manifestations of the same underlying physical process, although rarely modeled as such. We construct a physics-based model of the 2014 B\ar{\dh}arbunga dike, by far the best observed large dike ($> 0.5$ km$^3$) to date. We constrain the background stress state [...]

Microstructural Constraints on Magmatic Mushes under Kīlauea Volcano, Hawaiʻi

Penny E Wieser, Marie Edmonds, John Maclennan, John Wheeler

Published: 2019-05-06
Subjects: Earth Sciences, Geochemistry, Geology, Mineral Physics, Physical Sciences and Mathematics, Volcanology

Distorted olivines of enigmatic origin are ubiquitous in erupted products from a wide range of volcanic systems (e.g., Hawaiʻi, Iceland, Andes). Investigation of these features at Kīlauea Volcano, Hawai’i, using an integrative crystallographic and chemical approach places quantitative constraints on mush pile thicknesses. Electron back-scatter diffraction (EBSD) reveals that the microstructural [...]

Deeply buried ancient volcanoes control hydrocarbon migration in the South China Sea

Qiliang Sun, Christopher Aiden-Lee Jackson, Craig Magee, Xinong Xie

Published: 2019-04-17
Subjects: Earth Sciences, Physical Sciences and Mathematics, Volcanology

Buried volcanoes are increasingly identified in the sedimentary basins both on lands and continental margins. However, their roles on the post-eruption fluid flows are still poorly understood, which greatly influence the estimate of seal integrity and increase the hydrocarbon exploration/production risks. Here we use high-resolution 3D seismic reflection and borehole data from the northern South [...]

The 2018-2019 seismo-volcanic crisis east of Mayotte, Comoros islands: seismicity and ground deformation markers of an exceptional submarine eruption

Anne Lemoine, Pierre Briole, Didier Bertil, Agathe Roullé, Michael Foumelis, Isabelle THINON, Daniel Raucoules, Marcello de Michele, Pierre Valty, Roser Hoste-Colomer

Published: 2019-02-28
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics, Volcanology

On May 10th, 2018, an unprecedented long and intense seismic crisis started offshore, east of Mayotte, the easternmost of the Comoros volcanic islands. The population felt hundreds of events. Over the course of one year, 32 earthquakes with magnitude greater than 5 occurred, including the largest event ever recorded in the Comoros (Mw = 5.9 on May 15th, 2018). Earthquakes are clustered in space [...]

Reconstructing the Anak Krakatau flank collapse that caused the December 2018 Indonesian tsunami

Rebecca Williams, Pete Rowley, Matthew C. Garthwaite

Published: 2019-02-15
Subjects: Earth Sciences, Physical Sciences and Mathematics, Volcanology

Volcanogenic tsunamis are one of the deadliest volcanic phenomena. Understanding their triggering processes and mitigating their effect remains a major challenge. On 22 December 2018, flank failure of the Anak Krakatau volcano in Indonesia generated a tsunami which killed more than 400 people. This event was captured in unprecedented detail by high-resolution satellite imagery and eyewitness [...]

Further evidence for magmatic bias in 14C dating of the Taupo and other major eruptions: response to Hogg et al.

Richard N. Holdaway, Brendan Duffy, Ben Kennedy

Published: 2019-02-11
Subjects: Earth Sciences, Physical Sciences and Mathematics, Volcanology

We appreciate the opportunity to respond to Hogg et al.’s critique of HDK182. We consider that neither the arguments nor the additional data presented by Hogg et al. provides a basis for rejecting our hypothesis of magmatic carbon bias in proximal 14C ages for the Taupo eruption. Hogg et al. focus on the wiggle match and Kaipo Bog dates out of > 40 data points, whereas our paper focused on the [...]


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