GeoLog

Natural Hazards

Geosciences Column: The calamity of eruptions, or an eruption of benefits?

Geosciences Column: The calamity of eruptions, or an eruption of benefits?

So here is a question: why would anyone want to live in the vicinity of an active volcano? The risks are well known, with hazards arising from lava flows, lahars, ash falls, debris avalanches, and pyroclastic density currents, with many often having deadly consequences. But despite the danger, more than half a billion people live in the direct vicinity of volcanoes. Could it be that communities proactively choose to settle in areas surrounding volcanoes; and if so, why? That is the very question research published earlier this year in the EGU open access Journal, Natural Hazards and Earth System Science (NHESS), seeks to address.

The team of scientists, led by Syamsul Bachri, a researcher at the University of Innsbruck, approach the question from a novel angle. Often, when studying hazards and risk management strategies associated with volcanoes, the focus is on the volcano itself, with researchers commonly taking a very scientific approach to the problem. Instead of focusing on how people are able to adapt to living near the constant threat of an erupting volcano, the new study takes a more holistic view: perhaps a volcano presents opportunities as well as hazards, and society and nature are complexly interlinked?

Previous studies of a similar nature found that people often live in hazardous regions due to a lack of hazard knowledge, a lack of alternatives and/or because they are forced to due to a marginalised social status. However, the new study considered a new option: ‘upside risks’, or opportunities, may offset some of the downsides of living in hazardous areas and should be taken into account in disaster risk reduction and management strategies.

In order to fully understand the complex interaction between humans and volcanoes the researchers used an approach which bridges social and natural sciences. They conducted a series of interviews and focus groups with communities living around Mt. Bromo in Java, Indonesia.

(Left) Bromo Volcano and its landforms: (1) Gunung Bromo and its crater; (2) a Strombolian cone, Gunung Batok; (3) complex of rest volcanic cone (G. Kursi); (4) complex of rest volcanic cone (G.Widodaren) and SegaraWedi; (5) Sand of Sea ; (6) Tengger caldera formation (upper and middle slope); (7) foot slope of Tengger caldera (Sukapura Barranco); (8) Sapi Kerep outlet valley (interpretation from SRTM Image and field survey.) (Right) Human–volcano system at Bromo Volcano. (1) Mt. Batok, (2) Bromo Volcano, (3) Mt. Kursi, (a) Ngadas Village, (b) Ranupane Village, (c) Ngadirejo Village, (d) Sumber Village, (e) Ngadisari Village, (f) Wonokitri Village, (g) Tosari Village, (h) Wringinanom Village. From Bachri et al., 2015.

(Left) Bromo Volcano and its landforms: (1) Gunung Bromo and its crater; (2) a Strombolian cone, Gunung Batok; (3) complex of rest volcanic cone (G. Kursi); (4) complex of rest volcanic cone (G.Widodaren) and SegaraWedi; (5) Sand of Sea ; (6) Tengger caldera formation (upper and middle slope); (7) foot slope of Tengger caldera (Sukapura Barranco); (8) Sapi Kerep outlet valley (interpretation from SRTM
Image and field survey.) (Right) Human–volcano system at Bromo Volcano. (1) Mt. Batok, (2) Bromo Volcano, (3) Mt. Kursi, (a) Ngadas Village, (b) Ranupane Village, (c) Ngadirejo Village, (d) Sumber Village, (e) Ngadisari Village, (f) Wonokitri Village, (g) Tosari Village, (h) Wringinanom Village. From Bachri et al., 2015. (Click to enlarge).

 

The volcano has erupted 56 times since 1804 and continues to be active today. The most recent eruption took place in 2010, and was sustained over a period of nine months. The estimated total economic loss was valued at USD ~15.5, affecting agriculture and the tourism industry, as well as causing significant loss of property. Disruption caused to the electricity supply, transport and water availability is more difficult to quantify. In total, 70,000 people, across 33 villages were affected by the eruption.

The communities living around the volcano are known as the Tenggerese, a Javanese ethnic minority, counting a population of about 600,000. The Tenggerese consider Mt. Bromo a deity and symbol of their culture. At lower altitudes, on the flanks of the volcano, they cultivate the fertile volcanic soils and raise livestock, while at higher altitudes they live as nomadic herds.

Despite the significant disruption caused to the Tenggerese by the 2010 eruption, the interviews conducted by the researchers revealed that the local communities benefited from the main resulting hazards: tephra fall, lahars and landslides. They found that the communities felt the effects of the eruption were negative whilst the eruption was ongoing and for a short period after. However, once the short-term disruption ended, the overall perception was one where the hazards presented opportunity.

Year and duration (days) of Mt. Bromo eruption in a 200-year period (for 1804–2010, CVGHM 2010; and for 2011–2012, Field survey, 2012).

Year and duration (days) of Mt. Bromo eruption in a 200-year period (for 1804–2010, CVGHM 2010; and for 2011–2012, Field
survey, 2012). From Bachri et al., 2015. (Click to enlarge).

Areas covered by volcanic ash and fine rock material could not be planted for two years following the eruption, but areas covered only by fine volcanic ash became more fertile. The Tenggerese farmers referred to this as Berkah Bromo (Bromo’s opportunity), and stated that Mt.Bromo provided benefits for the continuity of their livelihood.

The eruption also caused a number of lahars – volcanic mud flows known locally as lahar hujan – which destroyed some 20 houses. Despite the short-term negative effects of the lahars, agricultural productivity in the affected region was increased and is already being exploited by the local farmers. Bapak Kirno* (the head of Wrininganom village) stated during the interviews:

“Areas which are affected by lahar hujan from Bromo will be more fertile after some period if they are not dominated by sand materials.”

Landslides caused significant disruptions, in particular causing road accessibility problems, but at the same time, transferred fertile materials to new areas, contributing positively to soil quality.

(Top) Tenggerese priests during Dutch East Indies era which lasted from 1800 to 1949. (Bottom left) Tenggerese woman with two children. (Bottom right) Tenggerese priest holding a dedication ceremony of a new build house. (images provided to Wikimedia Commons by the Tropenmuseum, author unknown).

(Top) Tenggerese priests during Dutch East Indies era which lasted from 1800 to 1949. (Bottom left) Tenggerese woman with two children. (Bottom right) Tenggerese priest holding a dedication ceremony of a new build house. (images provided to Wikimedia Commons by the Tropenmuseum, author unknown). Click to englarge.

The research also found that volcanoes are a powerful force in shaping cultural identity. The essence of who the Tenggerese are is intrinsically linked to Mt. Bromo and they have a deep spiritual connection with the volcano. The Tenggerese believe that the attitude they have towards the mountain will play a role in how Mt. Bromo behaves towards them. Bapak Wahyu*, a participant of a focus group discussion, considers that the unusually sever 2010 eruption was a result of the abandonment of old customs. The younger generations used the benefits from plentiful agricultural yields, not to save in the traditional fashion, but to purchase unnecessary consumer gadgets. He argues this left villager’s ill prepared, with insufficient resources to survive the sustained eruption.

The interviews and focus groups allowed Bachri and his team to identify five ways in which the Tenggerese have culturally adapted to living in the shadow of Mt. Bromo and which have also enhanced their life. They have, not only a heightened resilience to hazards, but a greater capacity to recover from them, too. The limited and unique extent of the territory they inhabit gives the Tenggerese a strong local attachment and a deep knowledge of the hazard posed by the volcano. At the same time, their proximity to the volcano instils a sense of social and moral order and allows them to frame and voice dissent in a larger cosmological setting. Finally, volcanic eruptions are often the catalysts for change and this is largely viewed positively by the local inhabitants.

 “I am never scared of Bromo’s eruption because I always believe that this is temporary. Bromo’s eruption always benefit us. We believe that Bromo always gives us what we need to live here,” says Bapak Rudi*, Ngadirejo village official.

*All names used in the study were changed to protect the identity of the informants.

By Laura Roberts Artal, EGU Communications Officer

References

Bachri, S., Stötter, J., Monreal, M., and Sartohadi, J.: The calamity of eruptions, or an eruption of benefits? Mt. Bromo human–volcano system a case study of an open-risk perception, Nat. Hazards Earth Syst. Sci., 15, 277-290, doi:10.5194/nhess-15-277-2015, 2015.

Tilling, R.I.: Volcano hazard, in: Volcanoes and the Environment, edited by: Mart, J. and Ernst, G., Cambridge University Press, United States of America, 55-90, 2005.

Imaggeo on Mondays: Strombolian eruption

Imaggeo on Mondays: Strombolian eruption

Jonas Kuhn, a researcher at Heidelberg University , took the photograph during a field campaign at Stromboli volcano in Italy. The objective of this campaign was to gather data from different gaseous compounds of the volcanic plume. Via emission fluxes of volcanic gases (e.g. SO2, CO2, halogen compounds…) or the ratio of emitted gases, one can retrieve information about the interior of the volcano and magma dynamics. Volcanic gas measurements can therefore contribute to better understanding volcanoes and in predict volcanic activity.

There are several ways in which scientists can gather information about volcanic processes from plume gas measurements. Let’s start by taking a look at sulphur dioxide, as it is emitted by volcanoes in large amounts. A relatively novel measurement instrument, the SO2 Camera, is able to record 2D SO2 distributions with a high time resolution. This means that SO2 emission fluxes can be determined and linked to other volcanological data sets as e.g. seismic data or simply to the occurrence of explosions. The high resolution SO2 emission fluxe data can give insight into the footprints of volcanic processes like the bursting of gas bubbles in the magma. So depending on e.g. the viscosity of the magma one would expect different frequencies in the emission flux of different volcanoes.

“In our group, a lot of work was done on further developing such camera systems. In volcanology this technique has only been applied for the past decade,” explains Jonas.

Another innovative device for fast optical in situ measurement of SO2 andCO2, as well as chemical in situ measurements of halogen compounds in the plume was also tested during the field trip. By using the ratios of other gases to SO2 and the known SO2 flux (from the SO2 camera measurement), fluxes of the other gases can be estimated. Different gases have different solubilities in magma, so they are released from the magma at different pressures.  Ratios of gas abundances in the volcanic plume can therefore contain information on, for instance, changes in the magma level (it’s not uncommon for magma to be ‘invisible’ in the interior of the volcano). The magma level can also be a crucial indicator of volcanic activity.

“What made this field campaign special was that relatively new and young volcanic measurement techniques were tested and used,” outlines Jonas, who goes on to point out ““many of them are still in the development stages. The volcanic gas measurement field is very exciting at this time. Interesting insights have been gained in the last decades and there is still a lot of ideas and new technologies coming up.”

By Jonas Khun,  Researcher at Heidelberg University and Laura Roberts Artal, EGU Communications Officer

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/.

Film review: Revolution

Film review: Revolution

It’s not every day you are asked to review a film, and since it’s a documentary that encompasses a few of EGU’s sciences (such as climate sciences, biogeosciences, and energy, resources and the environment), I couldn’t say no. I’ll start by giving it a rating, 3.5/5 stars, though I would probably give it more if I were part of the film’s main target audience.

Revolution, by biologist-photographer turned filmmaker-conservationist Rob Stewart, is about some of the most pressing environmental issues of our time. It aims to educate the audience about ocean acidification, climate change, overfishing and deforestation, alerting them to how these issues can impact our planet and, in turn, humanity. But it’s also about much more than that.

The film starts with Stewart telling his own story, revealing how his personal experiences lead him to make his first documentary, Sharkwater, and how researching and promoting that film made him want to tell the broader story of Revolution. This makes for good story telling, and it’s an interesting and candid introduction (Stewart says at one point that he had no idea how to make a movie before Sharkwater). But it seems a tad overly dramatic at times and not always scientific in its claims. For example, to illustrate how humans, responsible for many environmental problems, can also be part of their solution, Stewart tells a crowd in Hong Kong that the “holes in the ozone layer are almost a figment of our imagination now”, which is not exactly true. According to a 2014 NASA release, the ozone hole is still roughly the size of North America, though it has been shrinking over the past couple of decades. I should point out, however, that while there are some minor scientific inaccuracies here and there in the film (and a glaring typo in a sentence where CO2 appears incorrectly written as CO2) the majority of the facts and figures cited in the movie do roughly seem to be accurate, even if rather dramatic and seemingly exaggerated at first.

The movie becomes more exciting (though, at times, depressing too) when Stewart changes the focus from his story to the story of how life evolved on Earth, and what its future might look like. The backdrop is beautiful footage, worthy of a BBC wildlife programme. Stewart starts where life itself started, underwater, and the images showing a diversity of corals and colourful fish (and the cute pigmy sea horse) are breath-taking and work well in illustrating his points. For example, as the colourful imagery gives place to shades of grey, Stewart describes and shows how corals have been affected by ocean acidification and rising temperatures.

Coral cover on the Great Barrier Reef has declined by 36% over the last 25 years. That's an enormous loss. Photo © Rob Stewart. From the documentary film Revolution.

Coral cover on the Great Barrier Reef has declined by 36% over the last 25 years. That’s an enormous loss. Photo © Rob Stewart. From the documentary film Revolution.

If the footage, both underwater and on land, makes for a stunning background, the interviews with various scientific experts bring home the film’s key messages. To me, they are the strongest aspect of Revolution. Stewart talks to credible researchers who are able to communicate their, often complex, science in clear language. Some of the readers of this blog may be able to relate to scientists Charlie Veron and Katharina Fabricius, whose field work is shown in the film, while viewers less familiar with the effects of ocean acidification on coral reefs will likely be moved by the dramatic words of these researchers.

What the scientists tell us will happen if humans continue in the business-as-usual path is indeed gloomy: deforestation increasing, fisheries collapsing, greenhouse gas emissions and temperatures on the rise at unprecedented rates, species going extinct en masse… the list goes on. The issues of deforestation and mass extinction are addressed when Stewart travels to Madagascar: the island’s tropical dry forests are home to unique animals and plants, many of which have seen their habitats destroyed by the burning of trees to make room for pastures and crops. Humanity’s dependence on fossil fuels is illustrated when Stewart talks about the Alberta tar sands, and how resource intensive and polluting it is to extract oil from them. A key message of the film is again illustrated here by one of the experts interviewed. Hans Joachim (‘John’) Schellnhuber, a scientific advisor to the German Government and director of the Potsdam Institute for Climate Impact Research, explains how stopping the Canadian tar sands project “is one of the decisive battles in the war against global warming”.

Indeed, Stewart sets out not only to inform people about the environmental issues faced by humanity, but also to encourage the audience to act on them: “Revolution is not just about the environment – it’s a film about hope and inspiration.” As such, Stewart balances out this negative outlook with examples of people who are standing up for climate justice and fighting for an end to fossil-fuel burning (and, sometimes, with clips of flamboyant cuttlefish and jumping lemurs!). Although it may not seem like it halfway through the film, the overall message is positive.

This is most evident when Stewart talks to young people, particularly those who travelled to Cancun, Mexico for the United Nations Climate Change Conference in 2010 (COP16). It is heartening to find out how committed and courageous some young people are in fighting for our future, their future, and in wanting to make the Earth a better place by changing human behaviour. This fighting spirit is best encapsulated in a speech by Mirna Haider, from the COP16 Lebanon Youth Delegation, which is particularly bold and moving, if impatient: “You have been negotiating all my life, you cannot tell me you need more time.”

Flamboyant Cuttlefish. Photo © Rob Stewart. From the documentary film Revolution.

Flamboyant Cuttlefish. Photo © Rob Stewart. From the documentary film Revolution.

Young people are those who may have the most to benefit from watching this film, and I think are the primary target audience of Revolution (there’s even an accompanying Educator’s guide with pre- and post-viewing resources and classroom activities teachers and parents might find useful). It inspires them towards (peaceful) revolution against corporations who profit from burning fossil fuels and from destroying natural resources, and against governments who take no action to stop them. It is a shame the film doesn’t address other ways in which individuals could help fight climate change, deforestation and ocean acidification, such as divesting from fossil fuels or eating less meat. But perhaps that’s something that resonates better with older people. Children and teenagers tend to be more optimistic about their power to save the Planet through revolution, and this film is sure to inspire them to act on the most pressing environmental problems the Earth faces.

Revolution premiered at festivals in 2012/2013, but has only been widely released earlier this year. You can watch the film online on the Revolution website, or through the platforms indicated there (sadly, it’s not free, but you can either rent it or buy it for only a few dollars, so it’s certainly affordable!).

 

By Bárbara Ferreira, EGU Media and Communications Manager

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.

 

Follow

Get every new post on this blog delivered to your Inbox.

Join other followers: