Tag Archives: natural hazards

Friday Field Photos: the Southern Volcanic Zone of Chile

30 Aug

If you are ever in Chile and have the chance to take a mid-morning flight south from Santiago towards Puerto Montt or Concepcion, make sure you try and book a window seat on the left hand side of the plane.  Once the early morning cloud has cleared, you could be in for a treat as you fly along the ‘volcanic front’, with spectacular views of Chile’s brooding volcanoes popping up from the landscape. Be sure to take a map, too, so that you can work out which one is which. The pictures below are roughly in order, flying from north to south – and several major volcanoes of the chain aren’t included.

There are several things to notice about these volcanoes – they are often in pairs, either as distinct but closely spaced mountains (Tolhauca and Lonquimay), or as ‘twin peaks’ forming the summit of an elongated massif (e.g. Llaima, Mocho Choshuenco). Many of the volcanoes are also clearly very young structures – forming wonderfully characteristic conical shapes (e.g. Antuco, Villarrica, Osorno). These cones must be younger than 15 – 20,000 years (and perhaps much younger than this), based on what we know about when the last major glaciation in the region ended. These cones sit on top of the lower-relief and older parts of the volcanoes, many of which have been reshaped by caldera-collapse, perhaps shortly after the ice retreated during deglaciation. The accessibility of the volcanoes of the Southern Volcanic Zone of the Andes makes this a wonderful place to study volcanic processes and volcano behaviour, both at the scale of individual eruptions, as well on the regional scale.

The river Cachapoal runs out of the Andes mountains, past the city of Rancagua

The river Cachapoal runs out of the Andes mountains, past the city of Rancagua

The saddle-shaped volcanic complex of Planchon-Peteroa (35.2 S), which last erupted in 2011.

The saddle-shaped volcanic complex of Planchon-Peteroa (35.2 S), which last erupted in 2011.

Cerro Azul volcano, Chile.

The spectacular ice-filled summit crater of Descabezado Grande volcano, Chile, at 35.6 S. The last eruption from this complex was in 1932, shortly after an eruption of the  nearby volcano Cerro Azul (or Quizapu).

View across the volcanoes of Tolhuaca (or Tolguaca, near ground) and Lonquimay (38.3 S). Both volcanoes are young, but it is not known when Tolhuaca last erupted. Lonquimay last erupted from 1988-1990.

View across the volcanoes of Tolhuaca (or Tolguaca, near ground) and Lonquimay (38.3 S). Both volcanoes are young, but it is not known when Tolhuaca last erupted. Lonquimay last erupted from 1988-1990.

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The young cone of Volcan Antuco, 37.4 S. Its last known eruption was in 1869.

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Twin-peaked Llaima (38.7 S) is one of the most active volcanoes of southern Chile, and last erupted in 2009.

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Volcan Sollipulli (39 S) has a spectacular ice-filled summit caldera, but is not thought to have erupted since the 18th Century

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Panorama across three young volcanoes, looking east: Villarrica (39.4 S) in front; the snow-covered sprawl of Quetrupillan in the middle ground; and the peak of volcan Lanin, on the Chile – Argentina border, in the distance.

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Villarrica, with a characteristic thin gas and aerosol plume rising from the open crater at the summit.

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The twin-peaked volcanoes Mocho Choshuenco (39.7 S). Choshuenco, thought to be the older vent, is the angular crag nearer the camera; Mocho is the small cone in the middle of the summit plateau. Mocho last erupted in 1937.

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Looking across a bank of cloud towards volcan Osorno (front, 41.1 S), and volcan Tromen, in the background. Osorno last erupted in 1869; Tromen is thought to have last erupted in 1822.

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Volcan Calbuco (41.3 S), which last erupted in 1972.

Data source: information on the recent eruptions of these volcanoes is all from the Smithsonian Institution Global Volcanism Project.

Further reading:

CR Stern, 2004, Active Andean volcanism: its geologic and tectonic setting. Revista geologica de Chile 31, 161-206 [Open Access].

SFL Watt et al., 2009, The influence of great earthquakes on volcanic eruption rate along the Chilean subduction zone. Earth and Planetary Science Letters, 277 (3-4), 399-407.

SFL Watt et al., 2013,The volcanic response to deglaciation: evidence from glaciated arcs and a reassessment of global eruption records, Earth-Science Reviews 122, 77-102.

Acknowledgements: my fieldwork in Chile over the past 10 years has been funded by NERC, IAVCEI and the British Council. Many thanks to my parents for introducing me to Chile and its volcanoes at the age of 7; and to Jose Antonio Naranjo and many others at SERNAGEOMIN for facilitating our continuing work in the region.

A Portmanteau of Natural Hazards

5 Dec

Last week, the UK’s Natural Environment Research Council (NERC) launched an over-arching programme in Natural Hazards, a network called PURE (Probability, Uncertainty and Risk in the Environment). This post is a very short attempt to navigate the maze of acronyms of projects that are either linked to PURE, or to other related initiatives in Natural Hazards in the UK.

PURE itself is a network, with funding for four years to support a range of activities in the natural hazards, mainly directed towards knowledge exchange and engagement with industry and policy-makers. PURE includes elements of the RCUK (Research Councils UK) Knowledge Transfer Networks in Financial Services (FSKTN) and Industrial Mathematics (IMKTN).

PURE also includes two major research consortia: RACER (Robust Assessment and Communication of Environmental Risk) and CREDIBLE (Consortium on Risk in the Environment: Diagnostics, Integration, Benchmarking, Learning and Elicitation), neither of which has a website as yet, but I’ll link to those when they are up.  The remit of PURE spans the spectrum of (physical) natural hazards ( including floods, extreme weather, tsunami, earthquakes and volcanic activity), while mainly focussing on UK or European case studies.

PURE intersects with another set of large-scale activities which have been jointly funded by the NERC and the Economic and Social Research Council (ESRC), under a programme called Increasing Resilience to Natural Hazards (IRNH). Most of the investment under this programme will be going into two international multi-partner consortia. Earthquakes without Frontiers (EwF) focusses on improving resilience in earthquake-prone regions of the Alpine-Himalayan mountain belt; while STREVA (Strengthening Resilience in Volcanic Areas) is a partnership with volcano observatories and other agencies in the Caribbean, Ecuador and Colombia. I wrote a little about STREVA‘s kick-off meeting on Montserrat in an earlier post. Both EwF and STREVA will shortly be supported by the appointment of two Knowledge Exchange Fellows, whose remits are likely to include bridging the gap between science and policy in natural hazards and risk both overseas, and in the UK. The call for KE Fellows is open until 12 February 2013.

Got that?  Do let me know if I have missed anything, and I shall update the post.

Links to information about the RCUK-funded Natural Hazards Consortia and Networks

A portmanteau is type of large suitcase

Montserrat: Open for Business

5 Oct

One of the great privileges of working on volcanoes is that you get the chance to visit some amazing places, and to meet some extraordinary people. Recently, I got the chance to return to Montserrat, a small volcanic island in the Caribbean which has been the site of a dome-forming eruption since July 1995. I had first visited Montserrat in early 1998, when I had a short tour as one of the staff scientists at the Montserrat Volcano Observatory which, at that time, was temporarily located in the north of the island.

In my report for the Cambridge Evening News for the first week of February 1998, I wrote ‘Montserrat’s volcano coughed back to life this week, and reminded us of its ability to make the lives of thousands of people miserable. Every eight hours there were pulses of earthquakes as avalanches of rock fell from the dome. None of these earthquakes was large enough to be felt, but during each pulse of activity vast orange-grey clouds of dust or ash rose from the volcano. These clouds drifted across the island, sprinkling everything with gritty powder. As the clumps land they break up into tiny dust particles which form an irritating, choking haze that coats everything with a stubborn grey film. In the space of two days, fifty thousand tonnes of ash smothered the island under a layer of what looks like cement powder.’ 

Ash clouds rising from the Soufriere Hills volcano, Montserrat, February 1998

At that time, the eruption was in its third year, and no-one really had much of an inkling of how long the activity might continue. The capital of Montserrat, Plymouth, had been permanently evacuated two years earlier and, by early 1998, the edge of the ‘exclusion zone’ extended well into the north of the island, leaving the communities of Salem, Olveston and Old Towne like ash-coated ghost towns.

Air-quality sampling during an ash fall, Montserrat, February 1998. Dr Lucy Ritchie in the driving seat.

Fourteen years on, I returned to Montserrat for the first time since 2000 for the initial workshop of an ambitious project called  ‘Strengthening Resilience in Volcanic Areas’ (STREVA), which brings together physical and social scientists from universities, observatories and research institutes from five (or more) countries.  Montserrat is a key place for us to start to begin to understand the factors (physical, social, societal, cultural, economic…) that influence how people and communities respond to, recover from and learn to live with volcanic eruptions.

A lot has changed on Montserrat in the intervening years. The eruption has continued, in pulses and pauses, and, if anything, it appears to have settled into a pattern of behaviour that is both familiar, and that can be lived with. Outside the immediate perimeter of the volcano, and the debris-strewn fans that tumble down its sides, much of the landscape has recovered. Salem and adjoining communities have been open for the past decade, and a purpose-built volcano observatory now occupies a prominent viewpoint overlooking the steaming volcano.  The island is green and vibrant and, even in the once-suburban areas that were last occupied seventeen years ago, gardens are splashed with the rich reds of bougainvillea and hibiscus. A quick comparison of the airport at Gerald’s (today, below),

The airport at Geralds, Montserrat, 2012

and the helipad that preceded it (in 1998, below) just gives a hint of how the physical infrastructure of the island has developed in recent years.

The helipad at Geralds, 1998. Dr Paul Cole (currently Director of the Montserrat Volcano Observatory) prepares for an observation flight.

‘Montserrat is open for business’ was the message from the current Governor of the island, Adrian Davis, as he opened the workshop. There are ambitious plans for the future, building new capacity for tourists and other activities in the north of the island, which has only occasionally been directly affected by the volcanic activity. But the strongest evidence for the strength of resolve of the residents of Montserrat, and of the bright signs for the future, came from the stories of those who lived through the darkest days of the eruption. In some of the most captivating and emotional talks I have been privileged to listen to, speaker after speaker took the audience on their personal journeys of survival and resilience. One common theme that came across was the role played by music in coping with the distress, hardship and loss experienced by communities across the island. Herman ‘Cupid’ Francis, was a teacher before the eruption, and is now three-time Calypso Monarch and Montserrat’s Director of Culture. He summed up the spirit of 1996, the height of the crisis when people were being displaced from their homes and livelihoods, with his song ‘when you go don’t go too far .. take the road that leads you home’.

An update on Santorini

13 Sep

As you may have heard by now, Santorini volcano has recently been showing some unrest. Of course, it has only just come to the attention of the media, some of which have taken things a little further than can be justified.  But for those of us involved in the work, this is a story which has taken rather longer to piece together.

In my own case, the story started 26 years ago this week, when I first stepped onto Santorini during the first few days of my PhD research. Santorini was hot, dusty and felt rather exotic as it was my first taste of Greece. These steps launched me into my research career in volcanology and culminated, as I thought at the time, with the publication of the ‘Santorini Memoir‘, which summarised our reconstruction of the volcanic history of the islands over the past 600,000 years or so. But Santorini is such an iconic place to visit, and the geology is just so well laid out, that there always were reasons to return. So when a new PhD student, Michelle Parks, arrived looking for a project that would involve both ‘remote sensing’ (in this case, satellite observation) with field work on a volcano, Santorini was the obvious choice for a study of how volcanoes behave in between eruptions. In Santorini’s case, the last very small eruption was in 1950, but there was a rich record of carefully observed eruptions stretching back to 1707: a gold mine of information from which  we could tease out ideas about how it might behave in the future. When we started work in early 2010, there had been no sign at all of any life in the volcano for as long as anyone could remember.

Three years on, and that has now all changed: the volcano has just had its first ‘sharp intake of breath‘ since the last eruption, with the arrival of a fresh pulse of molten rock into the shallow crust, four or five kilometers beneath the volcano. In the time it took for the scientific paper to pass through the peer review system the rumble of tiny earthquakes which heralded this period of unrest has quietened down, and the volcano seems to be returning to slumber for just a little longer. This time, though, everyone is watching.

References.

Hooper, A., 2012, Volcanology: a volcano’s sharp intake of breath. Nature Geoscience 5, 686–687, doi:10.1038/ngeo1584

Parks, MM et al., 2012, Evolution of Santorini volcano dominated by episodic and rapid fluxes of melt from depth. Nature Geoscience 5, 749–754, doi:10.1038/ngeo1562

 

Air photo of the northern part of Nea Kameni, the youngest of the volcanic islands of Santorini. Taken in May 2012 by the NERC Airborne Research and Survey team.