GeoLog

volcanology

Imaggeo on Mondays: Mount Etna

Imaggeo on Mondays: Mount Etna

In this week’s Imaggeo on Monday’s image an almost Martian looking landscape, with ombre coloured soils, gives way to gently rolling hills, covered in luscious woods and vegetation. Were it not for the trees in the distance, you would be forgiven for thinking this image had been captured by a Mars rover. In truth, it is an entirely more earthly landscape: welcome to the slopes of Mt. Etna! Keep on reading as Alicia Mourgán, a researcher at the University of València, gives an overview of the origin of the richly fertile soils and climate of Europe’s tallest active volcano.

Mount Etna is associated with the subduction of the African Plate under the Eurasian Plate. A number of theories have been proposed to explain Etna’s location and eruptive history: rifting processes, a hot spot, and the intersection of structural breaks in the crust. Scientists are still debating which best fits their data, and are using a variety of methods to build a better image of the Earth’s crust underneath the volcano.

The soil around the volcano is very rich in minerals, owing to its volcanic origin. It is composed of a number of eruptive materials of different ages, including ash, sand and desintegrated lava (from one or more flows). Volcanic rocks make some of the best soils on Earth: not only are they formed of a wide variety of common elements, these readily separate into their elemental forms.

In the Etna region there are substantial differences in climate, not only compared to the rest of Sicily, but also from one area of the volcano to another. This is due to the fact that the Etna region has semi-circular shape, spread from north to south-west. This characteristic allows for different environments to be formed each with its own microclimate, benefiting from different exposure and changing proximity to the sea. Altitude in the Etna region varies between 450 m and 1100m above sea level. This factor is the main reason for the temperature changes between the day and night and also across seasons.

Compared to the rest of Sicily, Etna is pretty wet too. The highest levels of precipitation are recorded on the east slopes of the volcano. Rain can be practically absent over the summer, but precipitation can also be very high during the autumn/winter period.

By Alicia Morugán, University de València, València, Spain

Imaggeo is the EGU’s online open access geosciences image repository. All geoscientists (and others) can submit their photographs and videos to this repository and, since it is open access, these images can be used for free by scientists for their presentations or publications, by educators and the general public, and some images can even be used freely for commercial purposes. Photographers also retain full rights of use, as Imaggeo images are licensed and distributed by the EGU under a Creative Commons licence. Submit your photos at http://imaggeo.egu.eu/upload/.

A journey into the Cordon Caulle volcano

A journey into the Cordon Caulle volcano

There is no escaping the fact that one of the perks of being an Earth scientist is the opportunity to visit incredible places while on field work. There is also no doubt that, geologist or not, walking on an active volcano is awe inspiring. Maybe you’ve had the experience of doing so yourself (if so, share your story with us in the comments section, we’d love to hear from you!), but if you haven’t then perhaps this post by Fabian Wadsworth, a volcanology PhD student at the Ludwig-Maximillian Universitat of Munich, Germany and part of the VUELCO project, might give you a feel for what it is like. In the post, Fabian describes his experience of journeying into the Cordon Caulle volcano, in Chile. A regular hiker of the German Alps, Fabian described the difference between climbing the impressive, but well-established trails of the Bavarian mountains to his trip to Chile: “a volcano, is dynamic on a large scale and provides little comfort at all. Hiking in active volcanic landscapes is, for me, more vivid and awakening for this reason.”

Ian Schipper with Jon Castro watching the mouth of the volcano churning out volcanic ash. Image Credit: Dr. Hugh Tuffen

Ian Schipper with Jon Castro watching the mouth of the volcano churning out volcanic ash. Image Credit: Dr. Hugh Tuffen

Dr. Hugh Tuffen, Dr. Ian Schipper and Prof. Jon Castro are volcanologists who study how magmas move, flow and explode on their way up to and over the Earth’s surface. They invited me to join them to Cordon Caulle in January 2014, just two years after it stopped erupting explosively in 2012. This team of researchers had been there in 2011 and in 2012 when it was most vigorously exploding and this post combines photographic reflections on their experience and some from my trip to give you a view of this place and the hike that led us into the volcano’s mouth.

This volcano is unique. It is a type of volcano that produces vast quantities of volcanic glass: obsidian. As well as erupting a huge volcanic cloud, typical of many eruptions, it slowly pushed out a dark tongue of obsidian that was hot enough to squeeze at glacial rates down and away from the source. This kind of eruption is rare and Cordon Caulle is the only time in history that such a phenomenon has been witnessed and studied. Scientists are working to understand how the region can be blanketed by volcanic ash – the result of massive explosions – while this seemingly gentle tongue is pushed out at the same time. In this way, obsidian is one of the most interesting materials to volcanologists and it draws us from all over the world to hike in these wonder-places.

From Puerto Monnt we travelled the 125 km northeast deep into the Andes. The hike to the volcano begins with a long journey through forest up to the highland plateaus. In 2012 this forested land was densely covered in ash from the volcano, Hugh told me, but by 2014 had fully recovered its lush green. From the plateau, the Andes unfold before you and make the many hours hiking feel insignificant. We carried our equipment as well as water, food and sleeping gear ready for a week or more spent in the shadow of the lava. In 2012, the noise of the eruption was intense and could be heard for kilometres around. By 2014-2015, all was quiet except for the buzzing of horseflies and the occasional creek from the heavy glass lava that still crumbled its way over the sand.

The forest land on the hike up in 2012. Hugh remembers the ash filling his hair and covering everything. Image Credit: Dr. Hugh Tuffen

The forest land on the hike up in 2012. Hugh remembers the ash filling his hair and covering everything. Image Credit: Dr. Hugh Tuffen

All around are the dunes of the highland plateaus, ribbed with rainwater gullies and patches of ice, which quench the thirst of hardworking volcanologists.

The dunes of the highland plateaus light up in the low sun. Image Credit: Dr. Hugh Tuffen

The dunes of the highland plateaus light up in the low sun. Image Credit: Dr. Hugh Tuffen

Walking from site to site is hard because the ash-laden sand is soft and sometimes you sink deep. Boots fill with pebble-sized volcanic shards that litter the ground from the last eruption. The distances are also deceptive. The lava, this slow-moving lava flow of glass, is almost forty meters high and many kilometres wide. We made basecamp at one end of the lava and each day hiked to places of interest, sometimes for hours, around the plateaus.

Hugh returned in 2015 yet again with Mike James and student Nathan Magnall and walked between slivers of cloud and tongues of glassy lava. Image Credit: Dr. Hugh Tuffen

Hugh returned in 2015 yet again with Mike James and student Nathan Magnall and walked between slivers of cloud and tongues of glassy lava. Image Credit: Dr. Hugh Tuffen

Starting before dawn, we took one day to set off for a place no one has seen before. We wanted to climb into the mouth of the volcano; into the vent from where the lava was being pushed out back in 2011 and 2012. No one has been into such a place before – the source of obsidian – and we thought that some of the observations we could make would hold a key to the puzzle of these eruptions. We hiked for hours around the great lava flow and to the back side of the vent area. We put on our gas masks to filter some of the still-circulating toxic volcanic gases and particles and we pulled our hats down against the fierce sun. We climbed the cone to the top and peered down into the vent area itself. From that vantage point we circled down the cone’s rim and into the vent proper. From there, gazing back up at the inner walls of the volcano, Hugh, Jon and Ian remembered watched this area explode and writhe just a few years before at the height of eruption. With an uneasy feeling, we set about learning what we could from the rocks and glass at the source of obsidian on our Earth’s surface.

Snatching our hard-won science, we returned to camp only after dark, hungry and thirsty and shared the small celebratory whisky ration we had brought with us. This day, inside the volcano, will remain among the most vivid in my life. And now, back in Munich, I can readily recall the sulfur smell and shine of the glass in that place.

Hugh, Ian and Jon will no doubt continue to return to this enigmatic place to learn more each year and will listen out for the next time obsidian erupts. Nathan Magnall has recently embarked on a PhD project focused on unveiling more of the mysteries of this place and Tuppence Stone, Toby Strong and Christiaan Munoz Salas, who joined Hugh in January 2015, filmed for the forthcoming BBC2 Patagonia series. You can also watch Hugh talk about Cordon Caulle in the video below too – skip to minute 13:00.

The poetry of the place should surely draw people from all disciplines to walk on those new stones – something I emphatically encourage you to do.

By Fabian Wadsworth, PhD Student Ludwig-Maximillian Universitat.

This post was originally posted on the Yetirama Blog. For the original post, please follow this link. We are very thankful to Dr. Hugh Tuffen for the use of his images in this post.

 

Studying an active volcano – in pictures

Studying an active volcano – in pictures

Santiaguito volcano in Guatemala is one of the most active volcanoes in Central America: currently erupting every 45-90 mintues, from its active lava dome Caliente, while at the same time sending a lava flow down its flanks. This makes it an ideal study object for volcanology. A group of volcanologists from the University of Liverpool, in the UK, installed a network of geophysical stations around the volcano in November 2014, (you can find out more about that trip here). They’ve since been back to Guatemala to download the data recorded by the stations and carry out some maintenance. This photo diary blog post, by Felix Von-Aulock, a postdoctoral researcher at the University of Liverpool, gives a snap shot of what it is like to carry out research on an active volcano: it’s challenging, packed full of adventure and rewarding in equal mesure!

Image credit: Felix Von-Aulock

Image credit: Felix Von Aulock

The Institute for Seismology, Volcanology, Meteorology and Hydrology (INSIVUMEH) are working hard to deliver updates on the activity of at least 3 erupting volcanoes to public, governmental bodies, and scientists. They do a really good job, despite the constant lack of funding, personel and equipment. This is our first stop on our way to Santiaguito, picking up equipment we left here last time, and catching up with Gustavo Chigna, a volcanolgist at INSIVUMEH.

Image credit: Felix Von-Aulock

Image credit: Felix Von Aulock

A few hours drive from Guatemala City, we finally see our destination, the Cerro Quemado/ Almolonga complex, with Santa Maria volcano (the tallest peak) in the background.

Image credit: Felix Von-Aulock

Image credit: Felix Von Aulock

It’s not all about the science! Guatemala is one of the biggest producers of coffee in the world and a lot of the volcanoes are surrounded by coffee plantations.

Image credit: Felix Von-Aulock

Image credit: Felix Von Aulock

While the volcanoes produce very fertile soils for the coffee to grow on, they can be very destructive. This farm at the base of Santiaguito has faced major hazards from lahars – torrents of hot or cold water, laden with rock fragments, ash and other volcaninc debris which hurtle down the flank of a volcano or valley following an eruption.

Image credit: Felix Von-Aulock

Image credit: Felix Von Aulock

The canyons fromed by the lahars cut right through the farm and the workers’ homes.

Image credit: Felix Von-Aulock

Image credit: Felix Von Aulock

Another hazard faced by the local communities is that posed by pyroclastic flows: high-density mixtures of hot, dry rock fragments and hot gases that move away from an eruptive volcaninc vent (as defined by the USGS).
Pictured above is the flow path of the pyroclastic flow of May 2014. The  flow paved the way for many Lahars which formed this canyon. The pyroclastic flow also nearly wiped out the volcano observatory and missed it only by 20m.

Image credit: Felix Von-Aulock

Image credit: Felix Von Aulock

In total we deployed 11 stations around the volcano. This trip’s main purpose was to maintain them and download the data aquired since they were installed in November 2014. We were excited to find that the first station we visited had actually been recording data until the week before we arrived. We were less excited to discover that bean plants were being planted right next to it, possibly leading to some ploughing noise in our data.

Image credit: Felix Von-Aulock

Image credit: Felix Von Aulock

Our room, three hours after our arrival. The chaos didn’t vanish, however, the smell got increasingly bad after 2 weeks of three guys sharing this room. Amongst the chaos, lots of expensive equipment and a kitten!

Image credit: Felix Von-Aulock

Image credit: Felix Von Aulock

After sorting out supplies and taking care of the stations at the base of the volcano in Quetzeltenango, we finally started our hike towards the active dome. While we (Felix Von-Aulock, pictured in the far right and Adrian Hornby, a volcanology PhD student, picture in the centre) went down towards Santiaguito Dome, Oliver, also volcanology PhD student, (pictured second from the right),  went to the top of Santa Maria to film with a thermal camera. Don Geronimo, on the far left, is a local who helped Oliver carry equipment and water to the 3700m high peak. Armando Pineda (second f. l) was our guide down the tricky path to the dome.

Image credit: Felix Von-Aulock

Image credit: Felix Von Aulock

It feels good to be finally walking after weeks of preparation and travelling, despite the packs being pretty heavy and the long day ahead of us.

Image credit: Felix Von-Aulock

Image credit: Felix Von Aulock

The first two days were hard work: a constant mix of rain and sun, heavy packs we were not quite used to yet and some extra walks made us feel sore pretty quickly.

Image credit: Felix Von-Aulock

Image credit: Felix Von Aulock

When there was rain, the sun would come out quickly thereafter and the beautiful surrounding made up for the hard work.

Image credit: Felix Von-Aulock

Image credit: Felix Von Aulock

A morning view from our campsite below the chain of domes that was formed during the last century. The riverbed below had a pretty decent river in it just the night before during a thunderstorm. We got caught by that thunderstorm, trying to move car batteries uphill, but luckily decided to turn around to the tent before the river and potential lahars would cross our route.

Image credit: Felix Von-Aulock

Image credit: Felix Von-Aulock

The valley that leads to the active dome (Agua de Caliente) is an always changing channel, washed out by the frequent lahars. Good to have an experienced guide like Armando with us.

Image credit: Felix Von-Aulock

Image credit: Felix Von Aulock

The combination of a thin layer of ash and the frequent rain made some sections a bit tricky with the heavy packs.

Image credit: Felix Von-Aulock

Image credit: Felix Von Aulock

Here we’re digging out the first station, from here on we need to wear helmets as we’re about 300m from the active dome.

Image credit: Felix Von-Aulock

Image credit: Felix Von Aulock

The stations combine measurements of the sound (infrasound), the volcano’s seismicity and the tilt of the flanks of the volcano.

Image credit: Felix Von-Aulock

Image credit: Felix Von Aulock

The volcano is erupting frequently and every hour or so, we can see an ash plume rising into the sky above our heads.

Image credit: Felix Von-Aulock

Image credit: Felix Von Aulock

An eruption of the lava dome of Santiaguito observed from our tent around 300m from the crater.

Image credit: Felix Von-Aulock

Image credit: Felix Von Aulock

We also brought along a little quadcopter to take pictures of the dome. And although it was not the main subject of our mission it proved quite successful (we didn’t crash it!) Trying to follow a tiny spot in the sky is not easy though. And I just kept thinking:

“This must be one of the best jobs in the world, flying a little helicopter over an active volcano!”

By Felix Von Aulock , Postdoctoral researcher at the University of Liverpool

We are grateful to Rüdiger Escobar-Wolf for helping us improve an earlier version of this blog post.

Do you have some stunning field work photographs that you’d like to share with the wider community? Why not upload them to the EGU’s online open access geosciences image repository, Imaggeo? Geoscientists (and others) can submit their photographs and videos to this repository and, since it is open access, these images can be used for free by scientists for their presentations or publications, by educators and the general public, and some images can even be used freely for commercial purposes. Photographers also retain full rights of use, as Imaggeo images are licensed and distributed by the EGU under a Creative Commons licence. Submit your photos at http://imaggeo.egu.eu/upload/

Field work is an intrinsic part of the geosciences and yet the stories behind data aquisition are often left untold in scientific publlications. If you’d like to share your field work and/or lab tales, we’d love to hear from you! Part of what makes GeoLog a great read is the variety that guest posts add to our regular features, and we welcome contributions from scientists, students and professionals in the Earth, planetary and space sciences. Got an idea? If you would like to contribute to GeoLog, please send a short paragraph detailing your idea to the EGU Communications Officer, Laura Roberts  at roberts@egu.eu.

 

Imaggeo on Mondays: Hekla’s history

Iceland is well known for its extensive volcanism. Situated amid the northernmost part of the Mid-Atlantic Ridge, the spreading centre is a hub of volcanic activity, from Krafla in the north to the young volcanic island of Surtsey in the south.

Simplified geological map of Iceland, showing the country’s larger volcanoes. (Credit: Wikimedia Commons user Pinpin)

Simplified geological map of Iceland, showing the country’s larger volcanoes (click for larger). (Credit: Wikimedia Commons user Pinpin)

Hekla is one of the country’s most active volcanoes – both in terms of erupted material and eruption frequency, and lies at the heart of a 40 kilometre long, 7 kilometre wide volcanic system. This week’s Imaggeo on Mondays features a lava flow in Landmannalaugar, not far from the volcano:

“Lava outflow in Iceland” by Wolfgang Schwanghart, who took this photo at Landmannalaugar in the Icelandic highlands. This image is distributed by the EGU under a Creative Commons licence.

“Lava outflow in Iceland” by Wolfgang Schwanghart, who took this photo at Landmannalaugar in the Icelandic highlands. This image is distributed by the EGU under a Creative Commons licence.

The frequency of Hekla’s eruptions is reflected in its chemistry: long periods between eruptions correspond to the eruption of viscous, silica-rich magma known as rhyodacite, and shorter ones (30 years or fewer) result in the eruption of low-silica magmas, from andesite to basaltic andesite. Hekla’s historic eruptions have always begun explosively, but the magnitude and duration of this explosive period is dependent on the length of time between eruptions – the longer the gap, the more explosive the eruption.

Once the initial explosive phase is over, and the eruption becomes effusive Hekla releases large volumes of lava like the one above. Records show this is the case for all of the eruptions that have occurred during recorded history – the exception being the 1104 eruption, where it is not certain Hekla had an effusive phase.

The volcano has erupted in this pattern at intervals of about 55 years since the 1100’s. That is, until fairly recently. The last four eruptions occurred in 1970, 1980, 1991 and 2000, and may indicate that Hekla may be entering a new phase of activity – one characterised by relatively small, frequent eruptions.

The 1980 eruption of Hekla volcano. (Credit: Wikimedia Commons user Oxonhutch)

The 1980 eruption of Hekla volcano. (Credit: Wikimedia Commons user Oxonhutch)

References:

Gronvold, K., Larsen, G. , Einarsson, P. , Thorarinsson, S. and Saemundsson, K.: The Hekla eruption 1980–1981, Bulletin of Volcanology, 46, 349-363, 1983.

Gudmundsson, A., Oskarsson, N., Gronvold, K., Saemundsson, K., Sigurdsson, O., Stefansson, R., Gislason, S. R. et al.: The 1991 eruption of Hekla, Iceland. Bulletin of Volcanology, 54, 238-246, 1992.

Lacasse, C., Karlsdóttir, S., Larsen, G., Soosalu, H., Rose, W. I., and Ernst, G. G. J.: Weather radar observations of the Hekla 2000 eruption cloud, Iceland. Bulletin of Volcanology, 66, 457-473, 2004.

Thorarinsson, S. and Sigvaldason, G. E.: The Hekla eruption of 1970. Bulletin of Volcanology, 36, 269-2888, 1972.

Imaggeo is the EGU’s open access geosciences image repository. A new and improved Imaggeo site will be launching soon, so you will be able to peruse an even better database of visually stunning geoscience images. Photos uploaded to Imaggeo can be used by scientists, the press and the public provided the original author is credited. Photographers also retain full rights of use, as Imaggeo images are licensed and distributed by the EGU under a Creative Commons licence. You can submit your photos here.