Preprints
Filtering by Subject: Volcanology
Time scales of shallow magma chamber replenishment at Campi Flegrei caldera.
Published: 2018-05-23
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics, Volcanology
Ascent of primitive magmas from depth into shallow, partially degassed reservoirs is commonly assumed to be a viable eruption trigger. The resulting processes of convection and mixing have played an important role both in pre- and syn-eruptive stages in many eruptions of different sizes at the unrest Campi Flegrei caldera in Southern Italy. We performed numerical simulations of magma chamber [...]
Extrusion dynamics of deep-water volcanoes
Published: 2018-05-15
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Volcanology
Submarine volcanism accounts for c. 75% of the Earths volcanic activity. Yet difficulties with imaging their exteriors and interiors mean the extrusion dynamics and erupted volumes of deep water volcanoes remain poorly understood. Here, we use high-resolution 3-D seismic reflection data to examine the external and internal geometry, and extrusion dynamics of two Late Miocene-Quaternary, [...]
The Mesozoic and Palaeozoic granitoids of north-western New Guinea
Published: 2018-05-09
Subjects: Earth Sciences, Geochemistry, Geology, Other Earth Sciences, Physical Sciences and Mathematics, Tectonics and Structure, Volcanology
A large portion of the Birds Head Peninsula of NW New Guinea is an inlier that reveals the pre-Cenozoic geological history of the northern margin of eastern Gondwana. The peninsula is dominated by a regional basement high exposing Gondwanan (Australian) Palaeozoic metasediments intruded by Palaeozoic and Mesozoic granitoids. Here, we present the first comprehensive study of these granitoids, [...]
Volcanic ash generation mechanisms: Fingerprints in phase distribution highlighted by QEMSCAN particle mineralogical analysis
Published: 2018-05-03
Subjects: Earth Sciences, Physical Sciences and Mathematics, Volcanology
Volcanic ash particle properties depend upon their genetic fragmentation processes. Here, we introduce QEMSCAN particle mineralogical analysis (PMA) to quantify the phase distribution in two ash samples collected during activity at Santiaguito, Guatemala and assess the fingerprint of fragmentation mechanisms. Volcanic ash from a Vulcanian explosion and from a pyroclastic density current resulting [...]
The shape and distribution of Maar craters using the MaarVLS database.
Published: 2018-04-12
Subjects: Earth Sciences, Physical Sciences and Mathematics, Volcanology
A maar crater is the top of a much larger subsurface diatreme structure produced by phreatomagmatic explosions and the size and shape of the crater reflects the growth history of that structure during an eruption. Recent experimental and geophysical research has shown that crater complexity can reflect subsurface complexity. Morphometry provides a means of characterizing a global population of [...]
Ambient noise image Campi Flegrei 2011-2013
Published: 2018-03-27
Subjects: Earth Sciences, Environmental Monitoring, Environmental Sciences, Physical Sciences and Mathematics, Tectonics and Structure, Volcanology
Earthquakes at Campi Flegrei have been low-magnitude and sparse for more than thirty years, denying onshore monitoring observations of their usual source for structural constraint: seismic tomography. Here, we used ambient seismic noise recorded between 2011 and 2013 to reconstruct period-dependent Rayleigh-wave velocity maps of caldera-wide structures and volcanic reservoirs. The lowest [...]
Investigation of variable aeration of monodisperse mixtures: implications for Pyroclastic Density Currents
Published: 2018-03-13
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Volcanology
The high mobility of dense pyroclastic density currents (PDCs) is commonly attributed to high gas pore pressures. However, the influence of spatial and temporal variations in pore pressure within PDCs has yet to be investigated. Theory suggests that variability in the fluidisation and aeration of a current will have a significant control on PDC flow and deposition. In this study, the effect of [...]
Mechanical models to estimate the paleostress state from igneous intrusions
Published: 2018-03-09
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Tectonics and Structure, Volcanology
Dikes and sills represent an important component of the deformation history in volcanic systems, but unlike dikes, sills are typically omitted from traditional paleostress analyses in tectonic studies. The emplacement of sheet intrusions is commonly associated with mode I fracturing in a low deviatoric stress state, where dilation is perpendicular to the fracture plane. Many natural examples of [...]
The stratigraphy and eruptive history of the Palaeogene Arran Volcanic Formation, western Scotland: a proximal record of caldera-forming eruptions
Published: 2018-02-02
Subjects: Earth Sciences, Physical Sciences and Mathematics, Volcanology
Caldera-forming volcanic eruptions are among the most dangerous, and can generate extensive pyroclastic deposits and deliver ash into global atmospheric circulation systems. As calderas collapse, the eruptions can deposit thick proximal ignimbrite sequences and thinner ignimbrites more distally. However, the proximal record of caldera collapse is often obscured by later intrusions, volcanism, [...]
Rift-related magmatism influences petroleum systems development in the NE Irish Rockall Basin, offshore Ireland
Published: 2018-01-29
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Tectonics and Structure, Volcanology
Large volumes of hydrocarbons reside in volcanically influenced sedimentary basins. Despite having a good conceptual understanding of how magmatism impacts the petroleum system of such basins, we still lack detailed case studies documenting precisely how intrusive magmatism influences, for example, trap development and reservoir quality. Here we combine 3D seismic reflection, borehole, [...]
The role of H2O on the extraction of melt from crystallising magmas
Published: 2018-01-25
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Volcanology
The segregation and accumulation of felsic melts, from crystallising crustal magma reservoirs, is essential for the chemical evolution of the crust and is a phenomenon preceding some of the largest eruptions on Earth. The physical properties of residual melt and magma and the time over which the conditions remain appropriate for melt extraction are important factors controlling the efficiency of [...]
Upscaling permeability in anisotropic volcanic systems
Published: 2018-01-11
Subjects: Earth Sciences, Physical Sciences and Mathematics, Volcanology
Permeability is an increasingly prevalent metric included in volcano modelling; however, it is a property that can exhibit anisotropy in volcanic environments. Permeability of a layered medium can be described by the arithmetic or harmonic means of the permeabilities of the constituent units, depending on the orientation of flow with respect to layering (i.e. flow parallel or perpendicular to [...]
Structural signatures of igneous sheet intrusion propagation
Published: 2017-12-08
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Tectonics and Structure, Volcanology
The geometry and distribution of planar igneous bodies (i.e. sheet intrusions), such as dykes, sills, and inclined sheets, has long been used to determine emplacement mechanics, define melt source locations, and reconstruct palaeostress conditions to shed light on various tectonic and magmatic processes. Since the 1970’s we have recognised that sheet intrusions do not necessarily display a [...]
Visions of Volcanoes
Published: 2017-12-03
Subjects: Earth Sciences, Physical Sciences and Mathematics, Volcanology
The long nineteenth century marked an important transition in the understanding of the nature of combustion and fire, and of volcanoes and the interior of the earth. It was also a period when dramatic eruptions of Vesuvius lit up the night skies of Naples, providing ample opportunities for travellers, natural philosophers, and early geologists to get up close to the glowing lavas of an active [...]
Scientific and risk-reduction benefits of involving citizens in monitoring volcanic activity
Published: 2017-11-21
Subjects: Earth Sciences, Environmental Monitoring, Environmental Sciences, Geology, Physical Sciences and Mathematics, Volcanology
Citizen science involves volunteers, regardless of scientific background, in conducting scientific investigations. Although the extent of citizen involvement varies, the reported benefits of such activities include: the generation of new knowledge; increased public understanding of and confidence in science, and ‘real-time’ insights into rapidly evolving events such as natural hazards. In [...]