Category Archives: Volcanoes

Andy Hooper receives 2016 AGU Macelwane Medal

Congratulations to COMET scientist Professor Andy Hooper, who has been awarded the American Geophysical Union (AGU) James B. Macelwane Medal in recognition of his contributions to the geophysical sciences.

a.hooper

Established in 1961, the medal is given to outstanding early career scientists who have shown depth, breadth, impact, creativity and novelty in their research.

Professor Hooper, who is also Co-Director of the Institute of Geophysics and Tectonics at University of Leeds, pioneered the development of new software (StaMPS) to extract ground displacements from time series of synthetic aperture radar (SAR) acquisitions.  StaMPS is now used widely across the Earth Observation community.

He also discovered a new link between ice cap retreat and volcanism via geodetic monitoring from space and subsequent modelling of the 2010 Icelandic volcanic eruptions, and played a significant role in the €6m FUTUREVOLC project, leading the long-term deformation effort to integrate space and ground based observations for improved monitoring and evaluation of volcanic hazards.

Alongside other COMET researchers, he was part of a team contributing to the international scientific response to the earthquake which devastated Nepal in April 2015.

Most recently, working with colleagues from Iceland, he has shed new light on how volcanoes collapse during major eruptions, focusing on the 2014-15 eruption at Bárdarbunga.

Eruption column and lava flow from the air on 22 September 2014. Credit:Thórdís Högnadóttir
Eruption column and lava flow at Bárdarbunga, 22 September 2014. Credit: Thórdís Högnadóttir

Professor Hooper will be presented with the award at the 2016 AGU Fall Meeting, where he will also be giving a talk at the Union Session focusing on the new generation of scientists, where he will also be conferred an AGU fellow.

Congratulations Andy from all your colleagues at COMET.

Read more about the latest AGU awards

Iceland volcano collapse explained

COMET scientists have helped to shed new light on how volcanoes collapse during major eruptions, in new research published in Science.

The study, led by the University of Iceland, investigated a recent collapse at Bárdarbunga Volcano, Iceland, during the biggest volcanic eruption in Europe since the huge event at Laki in 1784.

Eruption column and lava flow from the air on 22 September 2014. Credit:Thórdís Högnadóttir
Eruption column and lava flow from the air on 22 September 2014. Credit: Thórdís Högnadóttir

The largest eruptions on Earth are commonly associated with collapse of the roof of a volcano into a magma chamber below. As they are infrequent, however – only five caldera collapses were recorded during the twentieth century – the processes involved are poorly understood.

The Bárdarbunga eruption, which lasted from August 2014 until February 2015, produced 1.5 km3 of basaltic lava.  In the course of the eruption, the top of the volcano caldera gradually sagged downwards, leaving an elongated bowl shaped depression over 13 km long and up to 65 m deep.

Bárdarbunga from the north, showing the main subsidence bowl within the caldera. Credit: Magnús T. Gudmundsson
Bárdarbunga from the north, showing the main subsidence bowl within the caldera. Credit: Magnús T. Gudmundsson

The total volume of the subsidence was 1.8 km3 – similar to the total volume of lava erupted and injected into the crust , implying a strong link between the two.

COMET scientist Marco Bagnardi said: “We saw the events at Bárdarbunga as an opportunity to better understand caldera collapse, and used multiple techniques to investigate.”

COMET researchers used radar data from satellites to measure ground deformation at Bárdarbunga’s caldera over a number of 24 hour periods.  As the topography continually changed, these data revealed movement of faults that reached to within a kilometre or so of the surface.

Combined with other techniques, including airborne altimetry, high precision GPS, seismology,  radio-echo soundings, and ice flow modelling, the results were used to create a detailed picture and timeline of how the caldera was collapsing and why.

From 16 August 2014 – before the eruption began – magma had been migrating out of a chamber 12 km below the ground, forming a fracture in the Earth’s crust.  Continued monitoring during the event showed that the magma was moving sideways from the volcano, beneath the surface, before finally erupting at Holuhraun, 47 km to the northeast, two weeks later.

Bardarbunga dike
The eruption in Holuhraun on its fourth day (3 September 2014). Credit: Thórdís Högnadóttir

Further analysis showed that a few days after the initial migration, the outflow of magma activated faults around the edge of the caldera leading to a series of earthquakes, which marked the beginning of the caldera collapse.  The collapsing roof then acted like a piston forcing even more magma out of the chamber below, which in turn led to further collapse.

COMET scientist Professor Andy Hooper explained: “Through modelling many different data sets, we were able to show that the caldera collapse was caused by magma leaving the reservoir, and this in turn squeezed more magma out of the reservoir, forming a positive feedback. This mechanism led to much more magma being erupted than would otherwise have been the case, which explains how eruptions on an even larger scale can occur.”

Overall, between 12 and 20% of the magma had left the magma chamber when the caldera collapse began.

Summarising the research, Prof Hooper added: “This work has given us real insight into caldera collapse, not only at Bárdarbunga but also at even larger eruptions.  What’s particularly interesting is how the collapse of the magma reservoir and the flow out of it clearly amplify each other.”

The paper, available now in Science, is Gudmundsson et al. (2016) Gradual caldera collapse at  Bárdarbunga volcano, Iceland, regulated by lateral magma outflow, doi:10.1126/science.aaf8988.

Coupling volcanic gas emission measurements to computational models of conduit gas flow

A new paper published in Geophysical Research Letters by Tom Pering and Andrew McGonigle has combined fluid dynamical modelling of gas flow in conduits with high time resolution measurements of volcanic gas discharge for the first time, revealing new insights into the dynamics of Stromboli volcano.

Their work is based on a recently developed approach using ultraviolet cameras which enable measurements of volcanic gas emission rates with unprecedented time resolution – around 1 Hz – such that gas release patterns associated with rapid explosive and non-explosive basaltic processes, can be resolved for the first time.

Data were captured on Stromboli, where an intriguing coda of lifetime on the order of 10s of seconds was identified following each explosion. Computational models were also developed to simulate the upward flow of conduit filling, so called “Taylor bubbles”, which are believed to be responsible for explosions on Stromboli when they burst at the surface.

The numerical models reveal the fissioning of smaller bubbles from the Taylor bubble bases to generate a train of “daughter bubbles”, thought to be responsible for generating the post-explosive coda upon arrival at the surface.

This process could play a primary yet hitherto unconsidered role in driving the dynamics of strombolian volcanism, both on Stromboli and other targets worldwide, with significant implications for the magnitude of resulting eruptions.

Combining models with field observations in this way shows considerable promise for improving our understanding of how gases drive volcanic activity.

The full reference is:  T.D Pering, A. J. S McGonigle, M. R James, G. Tamburello, A. Aiuppa, D. Delle Donne, M. Ripepe Conduit dynamics and post-explosion degassing on Stromboli: a combined UV camera and numerical modelling treatment, Geophysical Research Letters 2016 DOI: 10.1002/2016GL069001

Airborne volcanic ash detection using infrared spectral imaging

A new paper in Scientific Reports, co-authored by COMET’s Tamsin Mather, has demonstrated for the first time that airborne remote detection of volcanic ash is possible.

Airborne volcanic ash is a known hazard to aviation, but there are no current means to detect ash in-flight as the particles are too fine for on-board radar detection and, even in good visibility, ash clouds are difficult or impossible to detect by eye.

The economic cost and societal impact of the Icelandic eruption of Eyjafjallajökull generated renewed interest in finding ways to identify airborne volcanic ash in order to keep airspace open and avoid aircraft groundings.

The research, led by COMET Board Member Fred Prata, involved designing and building a bi-spectral, fast-sampling, uncooled infrared camera device (AVOID) to examine its ability to detect volcanic ash more than 50 km ahead of aircraft.

Experiments conducted over the Atlantic Ocean, off the coast of France involved an artificial ash cloud being created from a second aircraft, using ash from the Eyjafjallajökull eruption itself.

The measurements made by AVOID,  along with additional in situ sampling, confirmed the ability of the device to detect and quantify ash in an artificial ash cloud.  This is the first example of airborne remote detection of volcanic ash from a long-range flight test aircraft.

The full reference is Prata, A. J. et al. Artificial cloud test confirms volcanic ash detection using infrared spectral imaging. Sci. Rep. 6; doi: 10.1038/srep25620 (2016).

Over what distances do volcanoes interact?

In the geological past, large eruptions have often occurred simultaneously at nearby volcanoes. Now, a team of COMET scientists from the University of Bristol uses satellite imagery to investigate the distances over which restless magmatic plumbing systems interact.

In a study published in the journal Nature Geoscience, the scientists use deformation maps from the Kenyan Rift to monitor pressure changes in a sequence of small magma lenses beneath a single volcano. Importantly, they find that active magma systems were not disturbed beneath neighboring volcanoes less than 15 km away.

The lead author, Dr Juliet Biggs, explained: “Our satellite data shows that unrest in Kenya was restricted to an individual system. Inter-bedded ash layers at these same volcanoes, however, tell us that they have erupted synchronously in the geological past. This was our first hint to compare observations of lateral interactions based on recent geophysical measurements with those from petrological analyses of much older eruptions.

The team, which includes a recently graduated PhD student Elspeth Robertson and Bristol’s Head of Volcanology Prof. Kathy Cashman, took this opportunity to compare observations from around the world with simple scaling laws based on potential interaction mechanisms. They found that stress changes from very large eruptions could influence volcanoes over distances of up to 50 km, but that smaller pressure changes associated with unrest require a different mechanism to explain the interactions.

Prof Cashman explained ‘Volcanology is undergoing a scientific revolution right now – the concept of a large vat of liquid magma beneath a volcano is being replaced by that of a crystalline mush that contains a network of melt or gas lenses. The interactions patterns observed in Kenya support this view, and help to constrain the geometry and location of individual melt and gas lenses.”

The study was funded by two major NERC projects: COMET, a world-leading research centre focusing on tectonic and volcanic processes using Earth observation techniques; and RiftVolc, which is studying the past, present and future behavior of volcanoes in the East African Rift.

The research paper, The lateral extent of volcanic interactions during unrest and eruption, was published online in Nature Geoscience on 15th February 2016.

Sentinel-1 satellite captures volcanic surface changes that reveal the flow below

Pablo Gonzalez’s work on the 2014 Pico do Fogo eruption has been featured in the AGU’s Eos magazine.

Pico do Fogo. Credit: Nicole Richter
Pico do Fogo. Credit: Nicole Richter

The research uses a new satellite imaging system to model the subsurface path of the magma that fed the eruption, and shows that Sentinel-1’s TOPS InSAR technique has the potential to be used to study other natural hazards, including earthquakes and landslides.

Read the full article at EoS

COMET heads to Santiaguito, Guatemala

Scientists from COMET are participating in a workshop, funded by the US National Science Foundation, to study Santiaguito volcano, Guatemala.

SUAS shot of an explosion at Santiaguito volcano,  January 9 2016
SUAS shot of an explosion at Santiaguito volcano, January 9 2016

Matt Watson, Luke Western and Kate Wilkins have been in Guatemala since January 2nd, acquiring data with a range of instruments including three UV camera systems, three additional mini-UV spectrometers, a multispectral infrared camera, a lightweight infrared camera and a Phantom II Small Unmanned Aerial System (SUAS).

<a href="http://tempcomet.leeds.ac site acheter viagra.uk/wp-content/uploads/2016/01/guatemala1.jpg”>SUAS selfie showing an array of IR and UV cameras
SUAS selfie showing an array of IR and UV cameras

The meeting, the first in a series of scientific and educational workshops to be held at an active laboratory volcano every two to three years, is lead by a selection of principal scientists who have different field-­based data collection expertise.

They, along with students and local scientists, conducted fieldwork just prior to the formal workshop.  During the main phase of the workshop additional participants, including other students and professionals, arrived and had an opportunity to both observe the field installations and participate in data collection.

Formal lectures, on both measurement techniques and recent findings on shallow conduit processes at Santiaguito, were given by the principal scientists on January 5th. Different groups then headed out for four days to make various observations and measurements of the volcano.

The focus for the following two days, the last of the workshop, was on breakout groups and hands‐on analysis of the multiple data types that were collected concurrently. Everyone participating in the workshop, including students and principal scientists, shared and received all the data products at the end of the workshop.

Following the workshop, analytical results, tools, and integrated products will be delivered to the participants and published electronically for the broader community.

Watson, Western and Wilkins, with Helen Thomas from Nicarnica Aviation, are now heading to both Pacaya and Fuego volcanoes. At Pacaya they hope to undertake a drone survey of the crater by adapting the Phantom II to fly the lightweight IR camera. At Fuego, they will acquire more imaging and spectral measurements of the volcano’s emissions and investigate installation of the multispectral infrared camera.

Tracking the Etna eruption

On the evening of December 2 2015, Sicily’s Mount Etna began to erupt for the first time in over two years, reaching a brief but violent climax in the early hours of December 3 which included lava fountains as well as a column of gas and ash several kilometres high. The event was among the most violent seen at Etna over the last twenty years.

Ash cloud from Mount Etna’s Voragine crater lights up the sky. Credit: Marco Restivo/Demotix/Corbis
Ash cloud from Mount Etna’s Voragine crater lights up the sky. Credit: Marco Restivo/Demotix/Corbis

Luckily, good weather meant that the eruption could be monitored with visual and thermal cameras from the Istituto Nazionale di Geofisica e Vulcanologia (INGV) Etna Observatory.  According to INGV reports, activity peaked between 02:20 and 03:10 GMT when a continuous lava fountain reached heights well above 1km; with some jets of volcanic material reaching 3km into the sky.  Although the eruption had more or less ceased by dawn, the volcanic cloud had blown northeast, causing ash to be deposited on the nearby towns of Taormina, Milazzo, Messina and Reggio Calabria.

The eruption has so far continued, repeating the behaviour seen earlier with tall lava fountains and eruption columns many kilometers high.  Updates can be found on the INGV webpage.

COMET scientists at the University of Oxford have been tracking the volcanic plume’s progress using data from the Infrared Atmospheric Sounding Instruments (IASI) on board ESA’s MetOp-A and MetOp-B satellite platforms.  These instruments can detect the presence of volcanic SO2 in the atmosphere, using methods developed by the University’s Earth Observation Data Group.

The results, which can be found on the IASI NRT web page, showed that by Friday 4 December the plume had reached an area between Crete and Iraq, containing 0.06 Tg (1012g) SO2.

Estimate of SO2 amount from IASI-A overpass on the morning of 3 and 4 December 2015, assuming the SO2 between 9 and 10 km altitude
Estimate of SO2 amount from IASI-A overpass on the morning of 3 and 4 December 2015, assuming the SO2 between 9 and 10 km altitude

By the morning of 7 December, the plume had travelled from Sicily to Asia, reaching as far as Japan and the Pacific Ocean.

Screenshot from IASI NRT webpage 7 December 2015
Screenshot from IASI NRT webpage 7 December 2015

Dr Elisa Carboni, a COMET researcher based at the University of Oxford, said: “This is a great example of how we can track volcanic plume using the near real time IASI service. ”

You can follow the volcanic plume on the IASI NRT web page.

 

 

Measuring the refractive index of volcanic ash – new paper in Journal of Geophysical Research

COMET scientists’ Tamsin Mather, David Pyle and Roy Grainger have a new paper in the Journal of Geophysical Research on the detection and quantification of volcanic ash.

Credit:BGS

This is extremely important to the aviation industry, civil defence organisations and those in peril from volcanic ash fall, using remote sensing techniques to monitor volcanic clouds and return information on their properties.

The paper presents the complex refractive index of volcanic ash at 450.0 nm, 546.7 nm and 650.0 nm from eruptions of Aso (Japan), Grímsvötn (Iceland), Chaitén (Chile), Etna (Italy), Eyjafjallajökull (Iceland), Tongariro (New Zealand), Askja (Iceland), Nisyros (Greece), Okmok (Alaska), Augustine (Alaska) and Spurr (Alaska).

You can find the full paper, Measurements of the complex refractive index of volcanic ash at 450, 546.7 and 650 nm in the Journal of Geophysical Research, doi: 10.1002/2015JD023521.   

COMET scientists analyse Calbuco eruption

On 22nd April Calbuco volcano, Chile, erupted for the first time since 1972 with very little warning. Plumes of volcanic ash reached heights of 16 km on the 22nd and up to 17 km in a second, longer eruption that began in the early hours of 23rd April.

Several thousand people were evacuated from villages closest to Calbuco , and ash fell over an area extending from the west coast of Chile to the east coast of Argentina, and grounded air traffic in Chile, Uruguay and Argentina.

COMET scientists have been using satellite data to analyse the event, in terms of both the emissions and changes to the shape of the volcano itself.  You can read more about the event here.

Figure 4. Data, spherical source elastic half space model and residuals for recent deformation at Calbuco [Bagnardi].
Data, spherical source elastic half space model and residuals for recent deformation at Calbuco [Bagnardi].