GeoLog

volcano

Imaggeo on Mondays: Hints of an eruption

Imaggeo on Mondays: Hints of an eruption

The photograph shows water that accumulated in a depression on the ice surface of Vatnajökull glacier in southeastern Iceland. This 700m wide and 30m deep depression [1], scientifically called an ‘ice cauldron’, is surrounded by circular crevasses on the ice surface and is located on the glacier tongue Dyngjujökull, an outlet glacier of Vatnajökull.

The photo was taken on 4 June 2016, less than 22 months after the Holuhraun eruption, which started on 29 August 2014 in the flood plain north of the Dyngjujökull glacier and this depression. The lava flow field that formed in the eruption was the largest Iceland has seen in 200 years, covering 84km2 [2] equal to the total size of Manhattan .

A number of geologic processes occurred leading up the Holuhraun eruption. For example, preceding the volcanic event, a kilometre-wide area surrounding the Bárðarbunga volcano, the source of the eruption, experienced deformation. Additionally, elevated and migrating seismicity at three to eight km beneath the glacier was observed for nearly two weeks before the eruption [3]. At the same time, seven cauldrons, like the one in this photo, were detected on the ice surface (a second water filled depression is visible in the upper right corner of the photo). They are interpreted as indicators for subglacial eruptions, since these cauldrons usually form when geothermal or volcanic activity induces ice melt at the bottom of a glacier [4].

Fracturing of the Earth’s crust led up to a small subglacial eruption at the base of the ice beneath the photographed depression on 3 September 2014. This fracturing was further suggested as the source of long-lasting ground vibrations (called volcanic tremor) [5].

My colleagues and I studied the signals that preceded and accompanied the Holuhraun eruption using GPS instruments, satellites and seismic ground vibrations recorded by an array of seismometers [2, 5]. The research was conducted through a collaboration between University College Dublin and Dublin Institute for Advanced Studies in Ireland, the Icelandic Meteorological Office and University of Iceland in Iceland, and the GeoForschungsZentrum in Germany.

The FP7-funded FutureVolc project financed the above mentioned research and further research on early-warning of eruptions and other natural hazards such as sub-glacial floods.

By Eva Eibl, researcher at the GeoForschungsZentrum

Thanks go to www.volcanoheli.is who organised this trip.

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/.

May GeoRoundUp: the best of the Earth sciences from around the web

May GeoRoundUp: the best of the Earth sciences from around the web

Drawing inspiration from popular stories on our social media channels, as well as unique and quirky research news, this monthly column aims to bring you the best of the Earth and planetary sciences from around the web.

Major Story

This month the Earth science media has directed its attention towards a pacific island with a particularly volcanic condition. The Kilauea Volcano, an active shield volcano on the southeast corner of the Island of Hawai‘i, erupted on 3 May 2018, following a magnitude 5.0 earthquake that struck the region earlier that day.

Since the eruption, more than two dozen volcanic fissures have emerged, pouring rivers of lava onto the Earth’s surface and spurting fountains of red-hot molten more than 70 metres into the air.  As of today, Kilauea’s eruption has covered about 3534 acres (14.3 square kilometres) of the island in lava, according to the U.S. Geological Survey’s most recent estimates.

The island’s volcanic event has dealt heavy damages to the local community, forcing thousands of locals to evacuate the affected area. On 4 May, the governor of Hawaii, David Ige, declared a local state of emergency, activating military reservists from the National Guard to help with evacuations. Over the month Kilauea’s eruption has engulfed nearby neighborhoods in an oozing layer of lava, overtaking 75 homes, blocking major roads, swallowing up many vehicles, and even briefly threatening a geothermal power plant.

Kilauea’s molten rock, with temperatures at about 1,170 degrees Celsius, is an obvious danger to the local Hawaiian community (one serious injury reported so far). However, the volcanic eruption presents many airborne hazards as well.

In addition to spewing out lava, the Kilauea eruption has projected ballistic blocks, some up to 60 centimeters across, and released clouds of volcanic ash and vog (a volcanic smog of sulfur dioxide and aerosols). The ashfall and gas emissions can create hazardous conditions for travel, produce acid rain as well as cause irritation, headache and respiratory issues.

Kilauea’s lava has steadily marched towards the coast of the Big Island, and recently reached the Pacific Ocean. This interaction of molten rock and ocean water has created plumes of laze (lava haze). Laze is essentially a cloud of acidic steam, mixed with hydrochloric acid and fine particles of volcanic glass. Coming into contact with the toxic vapour can result in eye and skin irritation as well as lung damage.  

Map as of 2:00 p.m. HST, May 31, 2018. Given the dynamic nature of Kīlauea’s lower East Rift Zone eruption, with changing vent locations, fissures starting and stopping, and varying rates of lava effusion, map details shown here are accurate as of the date/time noted. Shaded purple areas indicate lava flows erupted in 1840, 1955, 1960, and 2014-2015. (Image: U.S. Geological Survey)

While residents have been fleeing the the Kilauea-affected region, many scientists have rushed to the Big Island to study the eruption. A swarm of researchers have spent the month recording lava flow activity, measuring seismicity and deformation, monitoring ash plumes by aircraft, and taking samples on foot.

Many volcano scientists have also turned to social media to answer questions from the general public about the recent eruption (like why is the eruption pink? Can you roast a marshmallow with lava?) and bust volcano myths floating online (expect no mega-tsunami from this eruption). The EGU’s own early career scientist representative for the Geochemistry, Mineralogy, Petrology & Volcanology Division, Evgenia Ilyinskaya, was invited to explain some volcano lingo on BBC News.

The volcano’s eruption has been ongoing for weeks, with no immediate end in site. Lava flows are still advancing across the region and volcanic gas emissions remain very high, says the U.S. Geological Survey’s Hawaiian Volcano Observatory. You can stay up to date with the volcano’s latest activity on the agency’s site.  

What you might have missed

A team of scientists from the PolarGAP project have found mountain ranges and three massive canyons underneath Antarctica’s ice using radar technology. These valleys play an important role in channeling ice flow from the centre of the continent towards the ocean, according to the researchers. “If Antarctica thins in a warming climate, as scientists suspect it will, then these channels could accelerate mass towards the ocean, further raising sea-levels,” reports an article from BBC News.

Also in Antarctic news, the Natural Environment Research Council (UK) and the National Science Foundation (US) have announced an ambitious plan to determine the Thwaites Glacier’s risk of collapse. The rapidly melting glacier sheds off 50 billion tons of ice a year, and if Thwaites were to completely go under, the meltwater would contribute more than 80 cm to sea level rise. “Because Thwaites drains the very center of the larger ice sheet system, if it loses enough volume, it could destabilize the rest of the entire West Antarctic Ice Sheet,” according to an article in Scientific American. The research team plans to collect various kinds of data on the glacier and use this information to predict the fate of Thwaites and West Antarctica. The $25-million (USD) joint effort will involve about 100 scientists on eight projects over the course of five years, posing to be one of the largest Antarctic research endeavors undertaken.

Meanwhile, looking out hundreds of millions of kilometres away, scientists have made an interesting discovery about one of Jupiter’s potentially habitable moons.

A team of scientists uncovered a new source of evidence that suggests Europa, one of Jupiter’s moons, may be venting plumes of water vapour above its icy exterior shell. The researchers came across this finding while re-examining data collected by NASA’s Galileo spacecraft, which performed a flyby 200 kilometres above the Europa in 1997. While running the decades old data through today’s more sophisticated computer systems, the research team found a brief, localised bend in the magnetic field, a phenomenon that is now recognised as evidence of water plume presence. These new results have made some scientists more confident that NASA’s Europa Clipper mission, set to launch by 2022, will find plumes on Jupiter’s moon.

Links we liked

The EGU Story

A 2007 paper on global climate zones published in Hydrology and Earth System Sciences, a journal of the European Geosciences Union, has been named the most cited source on Wikipedia, referenced more than 2.8 million times. The Guardian and WIRED reported this story that neither Copernicus Publications nor the Australian authors of the paper were aware of.

EGU training schools offer early career scientists specialist training opportunities they do not normally have access to in their home institutions. Up until 15 August 2018, the Union now welcomes requests for EGU support of training schools in the Earth, planetary or space sciences scheduled for 2019.

In addition, the EGU will now accept proposals for conferences on solar system and planetary processes, as well as on biochemical processes in the Earth system, in line with two new EGU conference series named in honour of two female scientists. The Angioletta Corradini and Mary Anning conferences are to be held every two years with their first editions in 2019 or 2020. The deadline to submit proposals is also 15 August 2018.

And don’t forget! To stay abreast of all the EGU’s events and activities, from highlighting papers published in our open access journals to providing news relating to EGU’s scientific divisions and meetings, including the General Assembly, subscribe to receive our monthly newsletter.

 

Imaggeo on Mondays: A volcanic point of view

Imaggeo on Mondays: A volcanic point of view

It’s not every day that you can peer into a volcano, much less gaze out at the sky from the inside of one. The Algar do Carvão, or “the Cavern of Coal,” is one of the few places on Earth where you can explore the underground reaches of a volcanic site.

The volcanic pit is found on the island of Terceira, part of the Azores archipelago. This collection of islands is an autonomous region of Portugal, located in the Atlantic Ocean about 1800 kilometres west from the Portuguese mainland. The archipelago is an especially volcanic hotspot, situated on the border of three major tectonic plates: the North American, Eurasian and African Plates.

The Algar do Carvão is essentially an ancient lava tube, made up of a volcanic chimney, about 80-90 metres deep, which then opens up into secondary magma chambers. The chimney formed first roughly 3,200 years ago, in the wake of a volcanic eruption. Then a second eruption, occurring in the same spot 1,200 years later, created many of the magma chambers seen today.

A profile of the Algar do Carvão, based on a similar cutaway produced by “Os Montanheiros,” (Credit: Ruben JC Furtado / Wikimedia Commons)

Despite what the cavern’s title suggests, the volcanic site is not a source of coal, but rather named for the walls’ dark black, ‘sooty’ colour. The volcanic pit is actually better known by geologists and cave enthusiasts for its source of silica-rich stalagmites and stalactites, a feature not commonly found in this region. Scientists have hypothesized that the structures’ silicate composition could have come in part from the volcano’s past hydrothermal activity or its population of diatoms, microorganisms which contain silica in their cell walls.

As you can see from the lush flora featured in today’s photo, the Algar do Carvão is teeming with life. Vegetation blankets the mouth of the cone structure and many animal populations thrive in the cavern environment. The volcanic pit is also home to several species found only on the Azores islands, like the troglobian spider Turinyphia cavernicola and the Terceira Island scarab Trechus terceiranus.

References

Daza, D. et al.: Isotopic composition (δ¹⁸ O y δD) of silica speleothems of the Algar do Carvão and Branca Opala volcanic caves (Terceira Island, Azores, Portugal), Estudios Geológicos, 70, 2, 2014.

Borges, P. A. V., Carlos Crespo, L., Cardoso, P.: Species conservation profile of the cave spider Turinyphia cavernicola (Araneae, Linyphiidae) from Terceira Island, Azores, Portugal, Biodiversity Data Journal 4: e10274, 2016.

Nunes, J.C., J.P. Constância, M.P. Costa, P. Barcelos, P.A.V. Borges & F. Pereira: Route of Azores Islands Volcanic Caves. Associação Os Montanheiros & GESPEA (Ed.). 16, 2011.

Algar do Carvão, Associação Os Montanheiros

Natural Monument of Algar do Carvão, 2011 Regional Secretariat for Agriculture and Environment, Governo dos Açores

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/.

Imaggeo on Mondays: Iceland’s original birch forest

Imaggeo on Mondays: Iceland’s original birch forest

Iceland is a country of dramatically rugged landscapes. The region is home to sweeping valleys and mountain ranges, dotted with lava fields, large glaciers, hot springs and impressive waterfalls.

The territory is also notoriously treeless. As of 2016, forests only made up 1.9 percent of Iceland, according to the Icelandic Forest Service. However, about a thousand years ago the country’s landscape was far more vegetated, and remnants of Iceland’s original woodlands still exist today.

It is a common misconception that Iceland is too cold to sustain a forest. “On the contrary, it has been observed that, at the time of human settlement, birch woods and scrubs have covered large parts of Iceland,” said Marco Cavalli, a researcher at the Research Institute for Geo-Hydrological Protection in Italy and the photographer of today’s featured image. In fact, Iceland’s fossil evidence suggests that, before human settlement, 25-40 percent of the island was dominated by woodlands and thickets.

When humans migrated to the island about 1100 years ago, much of Iceland’s natural forests were chopped down to make way for fields and pastures. In the centuries following human settlement, intensive sheep grazing and volcanic eruptions prevented forests from regenerating. By 1950, less than one percent of the country was covered by trees.

Iceland’s vegetation-devoid state presents an environmental problem to local Icelanders, since the lack of trees, combined with the island’s volcanic activity, has left the land vulnerable to severe soil erosion. Since the soil conditions prevent vegetation from taking root, erosion has limited farming and grazing efforts. Iceland’s loose soil and strong winds are also responsible for damaging sandstorms.

Soil conservation and forestry services have made substantial efforts to repopulate the Icelandic environment with trees, just about doubling Iceland’s tree cover since the mid-20th century. However, there is still a long road ahead to reach the Icelandic Forest Service’s goal to see 12 percent of Iceland afforested by 2100.

This picture was taken by Cavalli while on a field trip in Rangárvellir, a southern region of Iceland near Gunnarsholt, the headquarters of the Soil Conservation Service of Iceland (SCSI). The workshop focused on the area’s severe degradation from both human activities and natural causes, and efforts to restore the ecosystem.

During the workshop he spotted this particular grove of dwarf birch trees. “I was impressed to see a small remnant patch of the Icelandic original birch forest resisting all these adverse conditions,” said Cavalli. “I would say this is a good example of nature fighting to survive.”

References

Forestry in a Treeless Land, Icelandic Forest Service

Changes in vegetation cover from the time of Iceland’s settlement, Icelandic Institute of Natural History

Vikings Razed the Forests. Can Iceland Regrow Them?, The New York Times

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/.