Results 161 to 170 of about 22,175 (200)

Clastic and core lava components of a silicic lava dome

Geology, 2009
The formation of a lava dome involves fractionation of the lava into core and clastic components. We show that for three separate, successive andesitic lava domes that grew at Soufriere Hills volcano, Montserrat, between 1999 and 2007, the volumetric proportion of the lava converted to talus or pyroclastic flow deposits was 50%–90% of the lava extruded.
G. Wadge, G. Ryan, E.S. Calder
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Internal fabric development in complex lava domes

Tectonophysics, 2009
Abstract Viscous lava extrusions were modeled using plaster of Paris with admixed magnetite dust which served as a tracer of the internal anisotropy of magnetic susceptibility fabric in model lava domes. Used analogue material showed pseudoplastic behavior and yield strength level proportional to increasing mixing ratio of plaster powder and water. A
Prokop Závada, Zuzana Kratinová, Vladimír Kusbach, Karel Schulmann   +3 more
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Characterising fracture patterns at growing lava domes

2021
<p>Volcanic domes form when lava is too viscous to flow away from an active volcanic vent; instead, the lava accumulates into a mound consisting of a hotter, ductile core and a colder, brittle outer layer. An existing lava dome grows when new material is injected into the core of the dome, causing the  outer layer to stretch ...
Amy Myers, Claire Harnett, Michael Heap, Eoghan Holohan, Thomas Walter   +4 more
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Numerical simulation of strain within lava domes

Journal of Structural Geology, 2004
Abstract A new analytical and numerical method is presented to assess 3D deformation within lava domes. The method allows any simultaneous combination of strain components, even that of a pure shear and six elementary simple shear components. The method's practical use is presented. Model results provide the following information for lava dome strain
Cécile Buisson, Olivier Merle
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The unique radar properties of silicic lava domes

Journal of Geophysical Research: Planets, 2004
Silicic lava domes exhibit distinct morphologic characteristics at scales of centimeters to kilometers. Multiparameter radar observations capture the unique geometric signatures of silicic domes in a set of radar scattering properties that are unlike any other natural geologic surfaces. Backscatter cross‐section values are among the highest observed on
Jeffrey J. Plaut, Steven W. Anderson, David A. Crown, Ellen R. Stofan, Jakob J. van Zyl   +4 more
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Morphology of lava domes inferred from numerical modeling

2020
<p>Several types of lava dome morphology can be distinguished depending on the flow rate and the rheology of magma. At an endogenous regime, magma is embedded inside the dome and fresh magma is not extruded on the surface; vice versa, at an exogenous regime, a fresh lava is extruded, and a lava obelisk is of particular interest ...
Alik Ismail-Zadeh, Oleg Melnik, Igor Tsepelev   +2 more
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Primary succession on lava domes on Terceira (Azores)

Journal of Vegetation Science, 2004
Abstract:Questions: Are the vegetation attributes significantly different among lava domes and among geomorphologic units as a result of age and soil features? Are the successional rates equal in all the geomorphologic units of the domes? Are the colonizer species of lava domes totally replaced by other species in the late successional stages?Location:
Elias, Rui B., Dias, Eduardo
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Viscoplastic Models of Lava Domes

1990
It is proposed that lava domes possess a yield strength whose magnitude governs their shape and explosivity. Theoretical and laboratory modelling of the spread of viscoplastic material over a horizontal surface provide means of examining geological data on dome growth in terms of dome rheology. Experiments using kaolin slurries show that a growing dome
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Timescales of texture development in a cooling lava dome

Geochimica et Cosmochimica Acta, 2013
Abstract Crystal growth and crack development in cooling lava domes are both capable of redistributing and mobilizing water. Cracking and hydration decrease the stability of a dome, which may lead to hazards including partial dome collapse and block and ash flows.
F.W. von Aulock, A.R.L. Nichols, B.M. Kennedy, C. Oze   +3 more
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Lava Dome Optimization Algorithm

Lava domes are dome-shaped structures in volcanic geology formed by the slow accumulation of high-viscosity lava. Their formation is characterized by slow accumulation, localized flow, and self-limitation, influenced by the lava viscosity, accumulation rate, and environmental constraints.
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