Tag Archives: volcano

Volcanoes of the Ethiopian Rift Valley

17 Nov

The great Rift Valley of Ethiopia is not only the cradle of humankind, but also the place on Earth where humans have lived with volcanoes, and exploited their resources, for the longest period of time. Perhaps as long ago as 3 Million years, early hominids began to fashion tools from the volcanic rocks from which the Rift Valley was floored, including basalt and obsidian.

IMG_7747_stitch Riftview

View into the Main Ethiopian Rift Valley, on the descent from Butajira to Ziway. Aluto volcano in the centre distance.

The Ethiopian Rift Valley is just one part of the East African Rift system – the largest active continental rift on Earth. While the Ethiopian rift hosts nearly 60 volcanoes that are thought to have erupted in the past 10,000 years, there is only very sparse information about the current status of any of its ‘active’ volcanoes. There are historical records for just two or three eruptions along the MER: 1631 (Dama Ali), and ca. 1820 (Fantale) and (Kone). In contrast, the Afar segment of the rift includes one volcano known to have been in eruption almost continuously since 1873 (Erta Ale), and several other volcanoes that have had major recent or historical eruptions (Dubbi 1400 and 1861; Dabbahu, 2005; the Manda Hararo Rift, 2007, 2009; Dallafilla, 2008, and Nabro, 2011). So are the volcanoes of the MER simply declining into old age and senescence? Or do they continue to pose a threat to the tens of millions of people who live and work the land across this vast region?

IMG_7836_stitch Shalla

Panorama of Lake Shala, part of which fills the huge caldera of O’a volcano.

To address this question, and others, the NERC funded RiftVolc consortium is carrying out a broad-scale investigation of the past eruptive histories, present status and potential for future activity of the volcanoes of the Central Main Ethiopian Rift. This spans eleven known or suspected centres, several of which have suffered major convulsions of caldera-collapse and eruption of great sheets of ignimbrite across the rift floor in the distant past. The first challenge is to piece together the eruptive histories of these volcanoes over the past few tens of thousands of years, and this is something that starts with fieldwork designed to detect the traces of these past events in the rock record. The RiftVolc field team, led by post-doctoral researcher Karen Fontijn, and with doctoral students Keri McNamara (Bristol) and Ben Clarke (Edinburgh) and masters students Amde and Firawalin (AAU) are spending the next five weeks completing a rapid survey of the volcanic ash and pumice deposits preserved within the rift.

IMG_8378_stitch CorbettiEast

Panorama of the eastern caldera of Corbetti volcano.

The first challenge is to identify the tell-tale clues that the sequences of young rocks, soils and sediments contain volcanic deposits. Close to the volcano, we might expect an individual large explosive eruption to leave both thick and coarse deposits; but go too close to the volcano, and there may be so much volcanic material that it can become hard to identify the products of single significant eruptions, as opposed to the ‘background noise’ of smaller but more frequent eruptions.

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Karen and Keri examining the young pyroclastic rocks of Corbetti volcano

Out on the flanks of the volcano and beyond, we have the vagaries of geological preservation (did the pumice or ash land somewhere where it would then stay unmodified?) and erosion and weathering (removing or modifying the evidence) to contend with. Each of these factors will depend not only on the nature of the original deposit (how thick it was; what it was made from); but also on the environment in which the deposit formed (on a lake bed? the open savannah?  a forest? On a slope, or not?), and on the subsequent history of that environment (did the lake dry out, or continue to fill with sediment? Did the pumice become stabilised in the grass land; or did it get blown or washed away? How quickly did the soil and vegetation recover after the eruption? How deeply has weathering penetrated in the intervening millennia since the eruption?). Lots of questions to ponder!

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Shelly fossils from an ancient lake deposit, interbedded with pumice layers from Aluto volcano

Our long-term goal is to better understand what sort of hazards the Rift’s volcanoes pose to those who live on and around them. There are, of course, much greater immediate challenges to communities in the region linked to the competition for the natural resources (water, land) in this region; but the rapid development of geothermal prospects in the Rift does mean that we need to pay closer attention to the state of the volcanoes that are the source of the geothermal heat.

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Fresh road cut section through an obsidian lava dome and drape of pyroclastic rocks, on the way to Urji volcano and Corbetti’s new geothermal power plant

Aside from the volcanoes, the main Ethiopian Rift and its lakes make for a spectacular environment to work in. Despite receding lake levels and failing rains this year, there are vibrant patches of forest and a host of exotic birds and animals to enjoy.

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Pair of little bee eaters, Lake Awassa

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Flock of flamingo, Lake Chitu

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Marabou stork, Lake Ziway

 

 

 

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Camels eating Prickly Pear cactus, Corbetti

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Ethiopian Fish Eagle, Lake Ziway

Acknowledgements. RiftVolc is a NERC-funded collaborative research project. Many thanks to our Ethiopian collaborators at the Addis Ababa University School of Earth Sciences and the Institute of Geophysics, Space Science and Astronomy (IGSSA) for hosting us and facilitating the joint field campaign; and to Ethioder for providing field vehicles and excellent drivers.

Energy Poverty and Geothermal Energy Futures

7 Jul

Ethiopia is one of the most impoverished nations in the world, in terms of the number of people who live without access to electricity. The World Energy Outlook reported that in 2014, 70 million people in Ethiopia, or 77% of the population, have no access to electricity. Ethiopia is also one of the more volcanically-active regions of the world, with 65 volcanoes or volcanic fields that are thought to have erupted within the past 10,000 years – though few of these volcanoes have been studied in any detail; and fewer still are closely monitored.

Aluto

Geothermal power plant infrastructure at Aluto volcano, Ziway, Ethiopia.

One benefit of this abundance of young volcanoes is that the geothermal energy potential of the region is significant – offering the potential of accessible and renewable low-carbon energy. Further south, along an extension of the Great Rift Valley, Kenya is already taking steps to exploit geothermal energy, with an installed capacity by December 2014 of 340 MW and an ambition to increase this by at least an order of magnitude within the next 15 years. In Ethiopia, current capacity currently stands at around 7 MW – provided by the Aluto Langano Power Plant, which was the first operational geothermal power plant in the country. In Ethiopia, as in Kenya, there is considerable ambition to develop geothermal power further – with the several volcanic centres identified as having the potential to supply 450 – 675 MW by 2020. In a country where per-capita electric power consumption is just 52 kWh (100 times less than that in the UK), that’s a lot of new energy.

KONICA MINOLTA DIGITAL CAMERA

Entrance to the Ethiopian Electric Power Corporation Aluto Langano Geothermal power plant, in the centre of Aluto volcano, Main Ethiopian Rift Valley.

All of this interest in young volcanoes as potential sources of ‘clean energy’ provides a significant opportunity for geoscientists to try and find out a little bit more about their eruptive past, and their potential for future activity; and to work out where the hot fluids and gases that provide the geothermal prospect are stored within the crust.

PP systems soil - CO2 measuring equipment

Using a PP systems respiration chamber to measure the escape of CO2 from the ground surface across the volcano.

At Aluto volcano, work by Will Hutchison using imagery from an aircraft survey (to identify young faults and fractures), and a ground-based survey of where (natural) carbon dioxide is seeping out of the volcano at the present day, has helped develop a cartoon ‘model’ for this volcano. Our current view is that Aluto volcano currently leaks quite small amounts of heat and gas to the surface; mainly along long-lived fractures and faults, some of which have origins older than the volcano itself. Inside the volcano, fluids are trapped under layers of impermeable rock – perhaps two to three kilometres below the surface – where they are heated by the warm rocks of the volcanic hearth.

Hutchison et al 2015 figure

 

Planned drilling campaigns on Aluto, and on the neighbouring volcano and geothermal prospect, Corbetti, should eventually fill in some of the gaps in our geological knowledge; and help to transform the energy futures of some of the millions of people who live along the Ethiopian Rift valley.

References

Hutchison, W., T. A. Mather, D. M. Pyle, J. Biggs, G. Yirgu, 2015, Structural controls on fluid pathways in an active rift system: A case study of the Aluto volcanic complex. Geosphere, 11, 542-562, DOI:10.1130/GES01119.1 [Open Access]

Kebede, S., 2012, Geothermal Exploration and Development in Ethiopia: Status and Future Plan, in: Short Course VII on Exploration for Geothermal Resources, 14 pp.

Data Sources 

World Bank – Electric Power Consumption

World Energy Outlook, Africa

Taking the pulse of a large volcano: Mocho-Choshuenco, Chile

27 Apr

As the recent eruptions of Calbuco and Villarrica in southern Chile have shown, the long arcs of volcanoes that stretch around the world’s subduction zones have the potential to cause widespread disruption to lives and livelihoods, with little or no warning. Fortunately, neither of these eruptions has, so far, led to any reported loss of life – but the consequences  of these eruptions for the communities living within reach of the ash plumes and beyond will continue to play out for months or years into the future.

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The young cone of Mocho volcano, southern Chile, which may have erupted as recently as 1937. Mocho-Choshuenco volcano is one focus of our ongoing work in the region.

We have been working in southern Chile for a few years now, helping to extend what is known about past explosive eruptions at some of the region’s most active volcanoes. In this part of Chile, the written records of past eruptions only extend back a few hundred years – at the most – so most of our work has involved digging into the geological records of the region, to try and piece together the fragmentary stories of past eruptions. This can be slow and painstaking work, both in the field and in the laboratory, but is always exciting when things start to come together.

Field sampling on Mocho-Choshuenco volcano: deposits of the ‘Enco’ eruption.

This week, Harriet Rawson has published her first major scientific paper on the volcanic eruption history of Mocho-Choshuenco over the past 18,000 years. The 18,000 year timescale spans the volcanic activity that has taken place since the end of the last ice age; and we can be fairly confident that by visiting hundreds of sites around the volcano, we have found most of the ‘major’  eruptions, and many of the ‘moderate’ explosive eruptions from this volcano over this time period. The results of Harriet’s work are summarised in the picture below – which shows the timing, composition and sizes of eruptions through time. Just for context, the March 3 eruption of Villarrica was small (10 million cubic metres of ash, or magnitude 3 on the y axis), with a composition represented by an orange colour (so a bit like the Mocho eruptions around 4,000 years ago); while the April 22 eruption of Calbuco was moderate (210 million cubic metres of ash, or magnitude 4.5 on the y axis), and a composition in the green to pale blue range (like the eruption around 2000 years ago).

Mocho

The record of explosive volcanic eruptions at Mocho-Choshuenco volcano over the past 18,000 years (from Rawson et al., 2015). The x axis shows time, as ‘thousands of years before present’, based on radiocarbon dating of flecks of charcoal preseved within the deposits. The y-axis shows the ‘size’ of the eruption, in terms of the eruption magnitude, which is a logarithmic scale of erupted mass or volume of ash and pumice. The coloured curves represent the age and erupted composition of the volcanic events that have been recognised – with the ‘peak’ of the curve showing the best estimate of the eruption age, and size. The width of the curve gives an indication of the uncertainty in the timing of the eruption. The cartoon parallel to the x-axis shows how regional climate and ice cover at the volcano are thought to have changed over the same time period.

In many ways, this work is just the start of the forensic process of understanding how this particular volcano works and of the threats it might pose for the future;  but it is also a critical piece of the jigsaw in terms of understanding the pulse of the volcanic arc, and crossing the gap between the geological past, and the volcanic present.

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The wonderful ‘Salto Huilo Huilo‘ in the Huilo Huilo ecological reserve, at the foot of Mocho-Choshuenco.

Acknowledgements

This work has been funded primarily by the UK Natural Environment Research Council, and represents the outcome of many years of collaborations with colleagues from the Chilean Geological Survey, SERNAGEOMIN, with field work in the region supported by numerous colleagues and assistants, and with the support of CONAF and Reserva Huilo-Huilo.

References

K Fontijn et al., 2014, Late Quaternary tephrostratigraphy of southern Chile and Argentina, Quaternary Science Reviews 89, 70 – 84. [Open Access]

H Rawson et al., 2015, The frequency and magnitude of post-glacial explosive eruptions at Volcan Mocho-Choshuenco, southern Chile. Journal of Volcanology and Geothermal Research, doi:10.1016/j.jvolgeores.2015.04.003 [Open Access] Datasets available on figshare.

DM Pyle, 2015, Sizes of volcanic eruptions, Chapter 13 in Sigurdsson et al., eds, Encyclopedia of Volcanoes, 2nd edition, pp 257-264. doi:10.1016/B978-0-12-385938-9.00013-4

The great eruption of Tambora, April 1815

3 Apr
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Map of the Sanggar peninsula, on the island of Sumbawa, Indonesia, and the crater of Tambora. From Heinrich Zollinger’s 1847 expedition to the crater, published in 1855. From University of Oxford, Bodleian Library Collection.

April 2015 marks the 200th anniversary of the great eruption of Tambora, on Sumbawa island, Indonesia. This eruption is the largest known explosive eruption for at least the past 500 years, and the most destructive in terms of lives lost, even though the precise scale of the eruption remains uncertain. The Tambora eruption is also one of the largest known natural perturbations to the climate system of the past few hundred years – having left a clear sulphuric acid ‘fingerprint’ in ice cores around the world, and evidence for a strong causal link to the ‘year without a summer‘ of 1816, and global stories of inclement or unusual weather patterns, crop failures and famine.

Much of what we do know about the eruption and its local consequences is down to the efforts of two sets of people: Stamford and Sophia Raffles; and Heinrich Zollinger. In 1815, Thomas Stamford Raffles was temporary governor of Java; the British having invaded in 1811. Shortly after the eruption of Tambora, he gathered reports from people in areas affected by the eruption, and put these together in an ‘account of the eruption of the Tomboro mountain‘, which was published first in 1816 by the Batavian Society for Arts and Sciences, and later published posthumously by his wife, Lady Sophia Raffles, in her biography of his life and works (Raffles, 1830).

There is a considerable scientific literature (see references below) which has documented the main phases of the eruption, which began in earnest on April 5, 1815, and built to an eruptive climax on 10 – 11 April 1815. It is thought that the volcano had been rumbling for some time prior to this, perhaps as early as 1812; and some of the contemporary records collected by Raffles suggest that the first ashy explosions may have begun by about April 1, 1815. An extract from a letter from Banyuwangi, Java, 400 km west of the Sanggar peninsula, describes this stage of the activity:

At ten PM of the first of April we heard a noise resembling a cannonade, which lasted at intervals till nine o’clock next day; it continued at times loud, at others resembling distant thunder; but on the night of the 10th, the explosions became truly tremendous. On the morning of the 3rd April, ashes began to fall like fine snow; and in the course of the day they were half-an-inch deep on the ground. From that time till the 11th the air was continuously impregnated with them to such a degree that it was unpleasant to stir out of doors. On the morning of the 11th, the opposite shore of Bali was completely obscured in a dense cloud, which gradually approached the Java shore and was dreary and terrific.

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Heinrich Zollinger’s map of the inferred distribution of volcanic ash that fell across Indonesia following the eruption of Tambora in 1815. This may be the first example of an ‘isopach’ map of ash fallout from any volcanic eruption. From University of Oxford, Bodleian Library Collection.

The climactic phase of the eruption was very clearly described in an account by the Rajah of Sanggar, given to Lieutenant Owen Phillips, who had been sent to deliver rice for relief, and to collect information on the local effects of the eruption. ‘about seven PM on the 10th of April, three distinct columns of flame burst forth near the top of Tomboro mountain.. and after ascending separately to a very great height, their caps united in the air. In a short time the whole mountain next Sangar appeared like a body of liquid fire extending itself in every direction

In the main phase of the eruption, pyroclastic flows laid waste to much of the Sanggar peninsula, causing huge loss of life; and leaving a great collapse crater (caldera) where there had once been a tall volcanic peak.

Heinrich Zollinger was Swiss botanist, who moved to Java in 1841. In 1847, he led an expedition to Tambora and was the first scientist to climb to the crater rim since the eruption. In a short monograph, published in 1855, Zollinger describes his ascent of the volcano, documents the severe local impacts of the eruption, and details the numbers of people on Sumbawa affected by the eruption:

Location Killed in the eruption Died of hunger, or illness Emigrated
Papekat 2000
Tambora 6000
Sangar 1100 825 275
Dompo 1000 4000 3000
Sumbawa 18000 18000
Bima 15000 15000
Total 10100 37825 36725

Zollinger also estimated that at least 10,000 also died of starvation and illness on the neighbouring island of Lombok; and current estimates for the scale of the calamity are that around 60,000 people died in the region.

The bicentennial of the eruption of Tambora is a sobering moment to reflect on the challenges that a future eruption of this scale would pose, whether it were to occur in Indonesia, or elsewhere. Our present-day capacity to measure volcanic unrest should certainly be sufficient for a future event of this scale to be detected before the start of an eruption; but would we be able to identify the potential scale of the eruption, or its impact, in advance? Much remains to be done to prepare for and mitigate against the local, regional and global consequences of a repeat of an explosive eruption of this scale – and we still have more to learn by taking a forensic  look back at past events.

References

Auker, MR et al., 2013, A statistical analysis of the global historical volcanic fatality records. Journal of Applied Volcanology 2: 2

Oppenheimer, C., 2003, Climatic, environmental and human consequences of the largest known historical eruption: Tambora volcano, Indonesia, 1815. Progress in Physical Geography 27, 230-259.

Raffles, S, 1816, Narrative of the Effects of the Eruption from the Tomboro Mountain, in the Island of Sumbawa on the 11th and 12th of April 1815, Verhandelingen van het Bataviaasch Genootschap van Kunsten en Wetenschappen [via Google Books]

Raffles, S, 1830. Account of the eruption from the Tomboro Mountain, pp 241-250; in Memoir of the life and public service of Sir Thomas Stamford Raffles, F.R.S. &c: particularly in the government of Java, 1811-1816, and of Bencoolen and its dependencies, 1817-1824, with details of the commerce and resources of the eastern archipelago, and selections from his correspondence. London, John Murray.

Self, S, et al., 1984, Volcanological study of the great Tambora eruption of 1815. Geology 12, 659-663.

Sigurdsson, H. and Carey SN, 1989, Plinian and co-ignimbrite tephra fall from the 1815 eruption of Tambora volcano. Bulletin of Volcanology 51, 243-270.

Stommel, H and Stommel, E, 1983, Volcano weather: the story of 1816, the year without a summer. Seven Seas Press, Newport, Rhode Island.

Stothers, R.B., 1984, The great Tambora eruption in 1815 and its aftermath. Science 224, 1191-1198.

Zollinger, H., Besteigung des Vulkanes Tambora auf der Insel Sumbawa, und schilderung der Erupzion desselben im Jahr 1815. [Ascent of Mount Tambora volcano on the island of Sumbawa, and detailing the eruption of the same in the year 1815]

Links to online resources, and further reading

Bill McGuire ‘Are we ready for the next volcanic catastrophe?’The Guardian, 28 March 2015.

Gillen Darcy Wood ‘1816, The Year without a Summer’ BRANCH: Britain, Representation and Nineteenth-Century History. Ed. Dino Franco Felluga. Extension of Romanticism and Victorianism on the Net.

Haraldur Sigurdsson ‘Tambora: the greatest explosion in history’, a National Geographic photo gallery.

Tambora bicentennial – collection of papers in Nature Geoscience (Paywalled)

Gillen D’Arcy Wood’s Tambora; and an entertaining book review by Simon Winchester, author of ‘Krakatoa, the Day the World Exploded’

Anja Schmidt, Kirsten Fristad, Linda Elkins-Tanton (eds), Volcanism and Global Environmental Change, Cambridge University Press, 2015.

Villarrica erupts. March 3, 2015, Chile.

3 Mar
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Volcan Villarrica from the air in 2009.

 

Villarrica (Ruka Pillan in Mapudungun) is one of the most active volcanoes of southern Chile, and is a popular tourist destination in the heart of the Chilean Lake district. Villarrica has been in a continuous state of steady degassing for much of the past 30 years, since the last eruption in 1984-5, and began showing signs of increased unrest (seismicity, and visible activity in the summit crater) in February 2015. Eruptive activity at Villarrica in 1963-4 and 1971 was characterised by vigorous ‘Strombolian’ explosions from the summit – typically with short paroxysms of fire fountaining – followed by the formation of lava flows. The major hazards at Villarrica come from the lahars, which form as a result of the melting of snow and ice from the summit glacier by the intruding or erupting magma. In 1963 and 1971 the lahars that swept off the volcano caused considerable damage, and a number of fatalities in the affected areas.

At the present day, the volume of ice in the summit region is a little over 1 cubic kilometer. Any melt waters and lahars that may form as a consequence of the volcanic activity are expected to drain along any or several of the nine major lahar channels that were either active during the past eruptions of Villarrica, or have been identified from fieldwork and mapping. Recent work on the sediments from Lake Villarrica show that the transport of volcanic ash into the lake by lahars forms a very clear record of the small eruptions of the volcano that would otherwise not be preserved.

Lahar map

Map showing the nine major lahar channels (in blue) that drain off the summit of Villarrica, The area outlined in red shows the extent of the summit glacier field in Februiary 2011. The main tourist resort of Pucon, and lake Villarrica, lie to the north. In 1964, lahars caused  much damage to the village of Conaripe, to the south. Map from Rivera et al. (2015) , lahar channels from Castruccio et al. (2010).

The first Strombolian paroxysm from the 2015 eruption was reported shortly after 3 am local time on 3rd March; and this was followed by reports on social media of spontaneous evacuations from some of the communities that have been affected by lahars in the past. The Chilean agency responsible for civil protection (ONEMI, Oficina Nacional de Emergencia del Ministerio del Interior y Seguridad Pública) declared a ‘red alert‘ shortly afterwards, and SERNAGEOMIN also raised their technical ‘volcanic alert’ level to red. If the current phase of activity follows the pattern of past eruptions, there may be an extended period of elevated activity with intermittent paroxysms over the next few days to weeks.

This paroxysm just lasted a few tens of minutes, but released large puff of ash that rose to about 9 km above sea level and could be seen on geostationary weather satellites; a burp of sulphur dioxide that was visible from space, and coated the summit of Villarrica with a fresh coating of volcanic ‘spatter’.  On the volcano itself, there was clearly some melting of snow and ice, and small amounts of volcanic ash were washed down the local drainages, and into Lake Villarrica.

The footprint of the ‘hotspots’ associated with the freshly deposited ejecta can be seen in the alerts detected by University of Hawaii’s MODIS Thermal Alert System, using imagery from the MODIS sensors onboard NASA’s Terra and Aqua satellites.

MODVOLC screen shot

Screen shot of the ‘thermal alerts’ detected by the HIGP MODIS Thermal Alert System for Villarrica, on 3 March 2015.

Update – March 5th, 2015.

The eruption was over quite quickly, and although a few thousand people evacuated at the time, most returned home later that day. Flights over Villarrica by the volcano monitoring and civil protection teams on March 3rd, and subsequent days, showed that the summit vent became sealed by fresh spatter during the eruption, but signs of activity diminished very quickly. SERNAGEOMIN reported that only one monitoring station was lost during the eruption, and their current scenario is that there may be some intermittent weak Strombolian activity in the near future, which should be readily detectable on the monitoring systems. Photographs posted on social media showed only little evidence for limited damage by lahars during this first eruption; including damage to a tourist centre on the volcano slopes.

Ongoing Activity

Latest status reports from ONEMI, Chile

Latest status reports from SERNAGEOMIN, Chile

Latest webcam images of Villarrica, from SERNAGEOMIN

Latest Volcanic Ash Advisories from the Buenos Aires VAAC

Further information

Great video footage of the 3rd March eruption from 24Horas

Collections of photos and video from BioBioChile24Horas, Cooperativathe Guardian and SERNAGEOMIN.

Villarrica on Volcano Top Trumps

Villarrica pages at the Smithsonian Institution Global Volcanism Programme.

References

Castruccio, A. et al., 2010, Comparative study of lahars generated by the 1961 and 1971 eruptions of Calbuco and Villarrica volcanoes, Southern Andes of Chile, Journal of Volcanology and Geothermal Research 190, 297-311.

Rivera, A. et al., 2015, Recent changes in total ice volume on Volcan Villarrica, Southern Chile, Natural Hazards 75: 33 – 55

M van Daele, J Moernaut, G Silversmit, S Schmidt, K Fontijn, K Heirman, W Vandoome, M De Clercq, J van Acker, C Wolff, M Pino, R Urrutia, SJ Roberts, L Vincze, M de Batist, 2014, The 600 yr eruptive history of Villarrica volcano (Chile) revealed by annually laminated lake sediments, Geological Society of America, Bulletin doi:10.1130/B30798.1

The destruction of St Pierre, Martinique: 8 May, 1902

8 May

May 8th marks the anniversary of one of the worst volcanic disasters on record: the destruction of St Pierre, Martinique, in 1902, at the climax of the eruption of Mont Pelée. Below are a snapshot of images from one of the contemporary accounts of the disaster, ‘The volcano’s deadly work‘, written by Charles Morris in 1902. This eruption followed just one day after a similarly destructive eruption of the nearby Soufrière of St Vincent.

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Original caption ‘The only photograph taken of the volcanic outbreak of Mt Pelee, May 8, 1902, during the height of the eruption, a scene as grand as it was appalling’. This shows ash clouds rising off the flanks of the volcano, presumably associated with the emplacement of the dense, hot pyroclastic ‘nuee ardentes’ that accompanied the eruption to devastating effect.

photo 4

Original caption ‘Interior of a steamship at St Pierre, after the whirlwind of fire’. There was considerable damage incurred to boats that were afloat offshore from St Pierre, as the hot ash clouds travelled a short distance across the water, and engulfed them.

photo 1

Original caption ‘The clock that told the story. The ruins of the hospital of St Pierre and the clock with the hands pointing to 7.50, which indicated the time at which the city was overwhelmed’.

Growth of the Kameni Islands Volcano, Santorini, Greece

18 Mar
Santorini

Surface morphology of the Kameni islands, Santorini, Greece, based on new submarine and surface mapping, published by Nomikou et al. (2014).

A new paper, published in the journal GeoResJ, reveals the intricate details of the volcanic Kameni islands that lie in the flooded caldera of Santorini, Greece. The Kameni islands started growing shortly after the explosive eruption that formed much of the present day caldera. For the past 3500 years or so these islands have grown in pulses, with each new eruption adding more material to the edifice. In this new paper, we have brought together high-resolution imagery of the seafloor with a digital elevation model of the parts of the islands that emerge above sealevel, and have used this to reconstruct the piecemeal growth of these islands from an analysis of their surface shape. Much more remains to be done, but the fascinating part of the work for me was the dawning recognition of just how little we know about the lifecycle of submarine volcanoes, and how much of the volcanic history of Santorini remains underwater, and essentially untouched.

Interpretation of the growth of the Kameni islands, Santorini, Greece, over the past 2000 years.

Interpretation of the growth of the Kameni islands, Santorini, Greece, over the past 2000 years. From Nomikou et al., 2014 (Supplementary dataset 2).

Acknowledgements

Funding for this project came from agencies in Greece, the United Kingdom and the United States. Submarine multibeam data were collected from R/V AEGAEO, of the Hellenic Centre for Marine Research (HCMR), in 2001 and 2006, with support from the National Science Foundation. Onshore data were collected during a Natural Environment Research Council Airborne Remote Sensing Facility (ARSF) campaign to the eastern Mediterranean in May 2012, with additional support from the National Centre for Earth Observation (NCEO) and COMET.

Reference

P Nomikou, MM Parks, D Papanikolaou, DM Pyle, TA Mather, S Carey, AB Watts, M Paulatto, ML Kalnins, I Livanos, K Bejelou, E Simou, I Perros, 2014, The emergence and growth of a submarine volcano: The Kameni islands, Santorini (Greece), GeoResJ 1–2, 8–18. [Open Access]

Dataset

LiDAR data from the NERC ARSF Campaign EU-12-12-137 to Santorini on figshare

Related posts

The Kameni islands, Santorini, Greece

Santorini: a volcano in remission

Update on the eruption of Gunung Kelud

19 Feb
Area – thickness plot for Kelut fall deposits.  1990 data from Bourdier et al., 1997 (not all proximal data are plotted).

Preliminary ash thickness – isopach area plot for the February 2014 Kelut eruption. 1990 data from Bourdier et al., 1997 (not all proximal data are plotted).

The dramatic eruption of Gunung Kelud, or Kelut, led to a flurry of images of ash appearing on many social media platforms, including Flickr, Instagram and Twitter. As an experiment in a volcanology class, we sought out images that we could locate on a map, and by classifying the ash deposits as ‘light’, ‘moderate’ or ‘heavy’, generated a very rough contour map of the ash fallout from the eruption. The data show, very crudely, an exponential decay of ash thickness away from the volcano, and allows us to estimate the amount of ash deposited across Java during the eruption. Our current estimate is that the eruption may have deposited the equivalent of 0.2 – 0.3 cubic km of magma across the region. There are considerable uncertainties in this value, but it does confirm that the 2014 eruption was indeed substantial, rating as a Magnitude 4 (VEI 4) event.

Fuller details can be found in a preliminary report: Ash fallout from the 2014 Kelut eruption.

The Kameni islands, Santorini, Greece

14 Feb

A glimpse of the spectacular Kameni or ‘burnt’ islands of Santorini, Greece from the air reveals in intricate detail the overlapping lava flows, explosion craters and fields of volcanic ash from which the islands have been built in successive eruptions over the past 2000 years, and more.

Air photo mosaic of the Kameni island of Santorini, based on images taken during a 2004 NERC Airborne Research and Survey Facility campaign

Air photo mosaic of the Kameni island of Santorini, based on images taken during a NERC Airborne Research and Survey Facility campaign in 2004, and published later in an open access paper (Pyle and Elliott, 2006). A high resolution (340 Mb) version of this image is now available from figshare.

Of course, what we can see from the air is just the literal ‘tip’ of the present-day volcano which has grown up within the flooded caldera of Santorini since the last major explosive eruption, the Minoan eruption of ca. 1600 BC. Historical records and accounts from as far back as the Greek geographer Strabo, suggest that there have been at least ten eruptions in and around the Kameni islands since 197 BC. It is quite likely that there have been more that either weren’t noticed (because they were underwater), or that have been forgotten about with the passage of time. The present day the Kameni islands have a volume of about 3 cubic kilometres (of lava), measured from the sea-floor, and must have grown up at an average rate of about 1 million cubic metres per year since the Minoan eruption.

Data sources.

The high resolution version of the composite aerial photograph of the Kameni islands is available to download from figshare,
http://dx.doi.org/10.6084/m9.figshare.928563

Link to the original paper: DM Pyle and  JR Elliott, 2006, Quantitative morphology, recent evolution and future activity of the Kameni islands volcano, Santorini, Greece, Geosphere 2 (5), 253-268  [Open Access]

Related web pages and posts.

A blog post from August 2013 – ‘Santorini: a volcano in remission

Some web pages introducing the volcanic history of the Kameni islands.

A volcanic retrospective: eruptions of the Soufrière, St Vincent

20 Jan

The records, reports and testimonies of past volcanic eruptions and their consequences contain a wealth of information from which we can learn valuable lessons. This, in a nutshell, is the starting point of one strand of the STREVA project, ‘Strengthening Resilience in Volcanic Areas‘, which is a large programme funded by two British funding agencies (NERC and ESRC) and directed from the University of East Anglia by Jenni Barclay. This week, researchers from the STREVA team met in a workshop on St Vincent, a luxuriantly vegetated volcanic island in the southern Caribbean, to see what can be learned from the past history of this volcano and how this learning can be used mitigate the risks of future volcanic activity.

Soufrière St Vincent lava dome and crater. Photo by Paul Cole, January 2014. https://twitter.com/PaulCole23

Spectacular view across the crater of the Soufrière St Vincent, showing the lava dome that erupted in the centre of the crater in 1979-1980, and signs of recent land-sliding. The crater walls have been gradually enlarged and re-cut by successive eruptions, and their internal layers reveal the past volcanic history of the Soufrière.
Photo by Paul Cole, University of Plymouth, January 2014.

aerial view south eastern corner and windward side of St Vincent

Aerial view of the south-east corner of St Vincent, looking north along the windward coast. Inland, the topography is rugged, and often heavily vegetated, and rises towards the active volcano, the Soufriere of Sty Vincent, which is hidden under cloud at the top left of the picture.  The new airport runway, at Argyle, runs across the brown strip of land forming the eastern-most headland.

St Vincent is a volcanic island, and part of the arcuate chain of the Lesser Antilles volcanic arc. The active volcano on St Vincent is called the Soufrière; a name that describes its sulfurous nature, and shared by other volcanoes in the Antilles including the Soufrière Hills volcano (Montserrat), and the Soufrière of Guadeloupe.  While the geological record of past eruptions of St Vincent stretches back for hundreds of thousands of years, the historical record of known eruptions is short, but dramatic.

The first known explosive eruption of St Vincent was in March 1718. By all accounts this was a major eruption, preceded by an extended period of felt earthquakes. While there are no known first-hand descriptions of this eruption, a writer, thought to be Daniel Defoe, published an “An account of the Island of St. Vincent in the West Indies, and of its entire destruction on the 26th March last” in the Weekly Journal or Saturday’s Post of July 5th, 1718 (also known as Mist’s Journal), based on correspondence from ships that had been in the vicinity. This describes a short, but violent explosive eruption  “They saw in the night that terrible flash of fire, and .. heard innumerable clashes of thunder”, and the fallout of ash far downwind “In the afternoon they were surpriz’d with the falling of something upon them as thick as smoke but fine as dust, and yet solid as sand ; some ships had it nine inches, others a foot thick, upon their decks; the Island of Martenico [Martinique] is covered with it at about 7 to 9 inches thick; at Barbadoes it is frightful, even to St. Christophers it exceeded four inches.” Defoe’s account became well known when it was later included in a collection of his works (Romances and Narratives, Volume 15, edited by George Aitken and published in 1895/6). 

The first detailed account of the crater of the Soufrière dates to 1784 – when Alexander Anderson, then curator of the Botanic Gardens of St Vincent, wrote an account of  “The mountain of Morne Garou in the island of St Vincent and the volcano in its summit“. This letter was published in the Philosophical Transactions of the Royal Society, along with a fabulous plate showing the crater, partly filled with water and with a steaming dome (of what we now know to be lava) at its centre. In many respects, this view is remarkably similar to the state of the crater at the present day.

The next major eruption of St Vincent occurred in 1812, in an event which was captured dramatically both in written reports, and in a painting by JMW Turner (The eruption of the Souffrier Mountains, in the Island of St Vincent, at midnight on the 30th of April, 1812, from a sketch taken at the time by Hugh P. Keane). The observer who provided the sketch, Hugh Perry Keane, was a barrister and plantation owner; his diary of the eruption survives in an archive in Virginia, but not the sketch.

account of 1812 eruption


Description of the eruption of the Souffrier Mountain on Thursday night the 30th April 1812, in the island of Saint Vincent’. Extract from the Report from the Committee on Petition of Persons Interested in Estates in the Island of Saint Vincent, Parliamentary Papers of the House of Commons, Printed by Command, 7 May 1813, pp 182-193. The same description was published in The Times newspaper of 30 June 1812.

British Parliamentary Papers from 1813 contain a ‘Description of the eruption of the Souffrier Mountain on Thursday night the 30th April 1812, in the island of Saint Vincent’ which introduces the volcano and describes the precursory activity. This account had previously been published in The Times newspaper, and appears to be based on written testimonies from residents on the island that had been sent to the newspaper.

The Souffrier Mountain, the most northerly of the lofty chain running through the centre of this island .. had for some time past indicated much disquietude; and from the extraordinary frequency and violence of Earthquakes, which are calculated to have exceeded two hundred within the last year, portended some great movement or eruption..“. This account also provides a vivid and detailed description of the short-lived but violent eruption, and its immediate aftermath: “The birth of May dawned like the day of judgement. A chaotic gloom enveloped the mountain, and an impenetrable haze hung over the sea with black sluggish clouds of a sulphurous cast; the whole island was covered with .. cinders, scoria and broken masses of volcanic matter.

A petition from landowners across the island to the British Government outlined the extent of losses and damage from the eruption, explaining that parts of the island “have suffered in an extreme degree; the showers of volcanic matter .. having covered the whole surface of the ground [in that area] about ten inches deep;.. but most providentially, not many lives were lost.”

Nearly a century went by before the next eruption; a hugely destructive event that began in earnest on 7th May 19o2, just a day before the destruction of St Pierre on the nearby island of Martinique, following the eruption of Mont Pelée. The 1902 –  1903 eruptions of St Vincent resulted in a great loss of life (at least 1500), and severe economic impacts, all of which were widely documented in articles and reports at the time. As a result, we have a fantastic archive of primary observations, data and material to work with as we set out to investigate, retrospectively, the nature and consequences  of the 1902 eruption – a type of event which has occurred three times in the past 300 years.

Documentary evidence from this eruption includes the correspondence, reports and photographs from the wonderfully named Tempest Anderson, an opthalmologist, photographer and early volcano-tourist.  Anderson was rapidly commissioned to make a field visit to the island, which he published in early 1903. As this letter to the Royal Society attests he was a stickler for detail, and his accounts and photographic records from the time make for astonishing reading.

SVAnderson


Letter from Tempest Anderson to the Assistant Secretary, Royal Society, from the Royal Society Archives.
Feb 15., 1903.
Dear Sir, with reference to the Plates for the Report on the Volcanic Eruptions in the West Indies which have been engraved by Collings from my negatives, I wish to inform you that Dr Flett and I have had great difficulty with Collings and have only at last with considerable perseverance been able to [over] get satisfactory proofs. As even now it is quite possible that some failures may occur when they are carefully printed I would be much obliged if you could arrange for printer pulls of all the plates be sent to me before the printing is finally proceeded with …’

Meanwhile, the details of the eruption and its effects are exhaustively recorded in Colonial Reports and Parliamentary Papers from the time.

Colonial Reports for 1902

Colonial Reports – Annual – for 1902-1903. St Vincent. ‘All minor events are eclipsed by the appalling eruption of the Soufrière volcano, which on 7th May awoke from its 90 years’ slumber to again hurl death and devastation over nearly one-third of the hapless Island of St Vincent‘, Edward J Cameron, Administrator.

After 1903, Soufrière St Vincent returned to a state of quiescence which wasn’t disturbed until 1971, when a remarkably quiet eruption built a new lava dome within the flooded crater of the volcano. This new activity, and the subsequent unrest on the nearby island of Guadeloupe in 1976, helped to stimulate the expansion of networks of instruments, including seismometers and tiltmeters, to monitor the volcano. This investment paid off quickly, with the rapid onset of new activity in 1979.

The 1979 eruptions began with only a very short period of unrest, starting with a strong local earthquake on April 12.  Eruptive activity began with a series of short-lived but violent explosions and that lofted a series of ash plumes, high into the sky on April 13, 1979; Good Friday. This heralded two weeks of vigorous activity that peaked with an 18 km high plume on April 17, and ended, with the cessation of measurable seismicity on April 29. After this, the eruption switched to the quiet extrusion of lava, slowly forming the dome that still sits in the crater today. The 1979 eruption caused much disruption, with 20,000 people evacuated to shelters, but no direct loss of life.

The Vincentian newspaper 20 April 1979

The Vincentian newspaper, Friday 20 April 1979 – one week into the eruption.

One of the goals of the workshop on St Vincent was to find out from the residents of St Vincent and neighbouring islands about the current awareness of volcanic risk, and risk communication. Participants included representatives of emergency management organisations both from St Vincent and the Caribbean region, as well as residents of St Vincent from all walks of life, including those with direct experience of the eruptions of the 1970’s, and people currently charged with reponsibilities across the spectrum of disaster management and response, both in the public and private sectors. This was a tremendous experience, and the STREVA team arel now working hard to analyse the results, develop new ideas and share understanding of how best to improve preparedness for future volcanic unrest and the response to future volcanic emergencies.

Discussions of how to respond to a volcanic scenario, guided by the current volcanic hazard map of St Vincent.

Workshop discussions of the likely response to a future volcanic scenario, focussing on the current volcanic hazard map of St Vincent.

Acknowledgements

I wish to thank archivists and librarians at the Royal Society, the Geological Society of London, the National Archives of St Vincent and the Grenadines, the Barbados Museum and Historical Society, the British Library, Cambridge University Library and the Bodleian Libraries, University of Oxford, for access to archives and literature sources. Many thanks also to Paul Cole for the wonderful photo of the crater, to Willy Aspinall for the trails to Daniel Defoe and JMW Turner, and to Anna Hicks and Jenni Barclay for all of their work in putting the workshop together.

The STREVA project is funded by UK Research Councils NERC and ESRC under the Improving Resilience to Natural Hazards programme.

The workshop on St Vincent was supported by the National Emergency Management Organisation (NEMO) of St Vincent and the Grenadines, the Caribbean Disaster Emergency Management Agency (CDEMA), and the University of the West Indies Seismic Research Centre and we acknowledge the support of many people and organisations both in St Vincent and across the Caribbean for their contributions to the discussions and for helping to make this event such a success.

Related Posts

Post on the Botanic Gardens of St Vincent and the Grenadines.

Report on the STREVA workshop on Montserrat, October 2012: Montserrat, Open for Business.

Field Photo, Soufrière Hills Volcano, Montserrat, 1998.

Post from Charly Stamper – Soufrière Saint Vincent on the blog Between a Rock and a Hard Place.