Strombolian eruption

Image processing on volcanoes

Collaborations

2012-Present. LMV, UMR 6524 CNRS (Andrew Harris)

In April 2010, the eruption of Eyjafjallajökull (Iceland) threw volcanic ash several kilometres up into the atmosphere, an event which led to air travel disruption across northwest Europe for six days and which included the closure of airspace over many parts of Europe. This crisis spotlighted the necessity to parameterise and simulate plume dynamics through emission, dispersion and fall out as to better model, track and forecast cloud motions and locations. This eruption was classified as a Strombolian to Sub-Plinian eruption type. Numerous volcanoes from the five continents produce strombolian eruptions, which are a relatively mild form of explosive volcanic activity. Strombolian eruptions are small explosive events, 100s to 1000s of meter in height which occur more frequently than Vulcanian. They are also notable for the brilliant incandescent parabolic arcs traced by their molten ejecta. Emission of bombs, blocks, lapilli, and minor coarse ash is common during normal explosive activity. Lava flows and ash-rich eruptions plus paroxysms that send ash clouds to several kilometers are also frequent events as well.

On Stromboli, Strombolian activity has been observed and studied over several centuries. Over this period, the constant evolution of technology and the proliferation of monitoring equipment has improved our understanding of conduit dynamics and explosive behavior. Active volcanoes emit heat through lava flows, domes, lakes, degassing and erupting vents. Remote measurements of heat emission from such active features provide insights into the physical processes governing the associated volcanic activity. However, analyses and modelling as well as post processing of thermal data are still not fully automated, and quantitative parameters to feed to the modelers and responders in near-real time remain difficult to extract and provide.

Since 2001, thermal camera video has been increasingly used to track, parametrize and understand dynamic volcanic events, such that the use of such a capability is beginning to eclipse that of the satellite-based perspective. However, the complexity and size of these data sets are compounding the current problem of ever-accelerating data dates so as to require development new and different methodologies. For ongoing volcanic events, parameters, such as mass flux, ascent (or spreading) velocity and plume or lava expansion spreading rate, are key for understanding the dynamics of the explosive and effusive eruptions and the source mechanisms that drive them.

In this project, we concentrate on the different components of strombolian eruptions at the full range of remote sensing spatial scales. These range from millimeters (for individual particles in single thermal camera pixels) to kilometers (for the entire features imaged with the satellite field of view). We aim to characterise volcanic emissions through thermal vision.

Several results on the project

Publications

. On the transition from strombolian to fountaining activity: a thermal energy-based driver. Bulletin of Volcanology, 78,15, 2016.

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. Plume tracking algorithm : Parameterisation of volcanic plume dynamics. In Proc of the 26th general Assembly of IUGG, Prague, 2015.

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. Anatomy of a strombolian eruption : Inferences from particle data recorded with thermal video. In Journal of Geophysical Research,120,4 : 2367–2387, 2015.

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. Algorithm for particle detection and parameterization in high-frame-rate thermal video. In Journal of Applied Remote Sensing, 8(1), 083549, 2014.

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. Modern Multispectral Sensors Help Track Explosive Eruptions. In EOS, Transactions American Geophysical Union, 94:321-328, 2013.

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. Full bandwidth remote sensing for total parameterization of volcanic plumes. IAVCEI, 2013.

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