Volcanoes of Peru 2: Nevado Sabancaya


Photo: IGP

As I have layed out in the previous Peru article, there are quite a handfull of interesting volcanoes in Peru; it’s hard to choose the next one to introduce here. I take Sabancaya, because it is one of the two currently rumbling (beside Ubinas), and we might get to hear more of it in the near future. However, as it is not a well researched volcano, and no devastating disasters have made the worldwide headlines in the last centuries, there is not a lot to find on the internet – other than travellogs about the nearby tourist attraction Colca Canyon, which indeed would be one of the first and most affected places in case of an eruption.



Sabancaya stratovolcano is a complex edifice located ~70 km NW of Arequipa, part of the Ampato volcanic group (or Ampato-Sabancaya Complex) and the most active volcano in southern Peru. Located on the saddle between 6288-m-high Ampato and 6025-m-high Hualca Hualca volcanoes, it is the youngest of these volcanic centers and the only one to have erupted in historical time.

Three Volcanoes Photo: Marie Thérèse Hébert

Three Volcanoes Photo: Marie Thérèse Hébert

Image NASA. Lava flows around Sabancaya.

Image NASA. Lava flows around Sabancaya.

Both Nevado Ampato and Nevado Sabancaya consist of a series of lava domes aligned along a NW-SE trend. The name of 5967-m-high Sabancaya, whose Quechua name is “Sahuancqueya” (meaning Spewing Volcano), first appeared in records in 1595 CE, suggesting historic activity prior to that date. Holocene activity has consisted of plinian eruptions followed by emission of voluminous andesitic and dacitic lava flows, which form an extensive apron around the volcano. Records of historical eruptions date back to 1750, with the largest in 1990 (a VEI 3).

1990-1998 ERUPTION

Photo: IGP

Photo: IGP

With unrest and phreatic explosions beginning in 1987, Sabancaya had a violent eruption in 1990, continued by vulcanian and phreatic explosions for the following eight years with relatively low lava output. The period of greatest activity was recorded between May 28 and June 5, 1990. Residents living near the volcano reported an explosive eruption from Sabancaya that began on May 28, 1990. Initially, several explosions occurred per day, producing plumes to about 2 km height. Activity intensified on June 4, and by the 8th explosions occurred at intervals of 5-10 minutes and ashfall covered a radius of 20 km. More-or-less constant ash emission continued until 1998. In this period the eruption column reached between 3 and 5 km above the crater, ejecting material a few hundred meters to 1 km height above the crater, with lapilli falling between 3 and 5 km from the crater and ash scattered between 20 and 30 km east of the volcano, covering about 250 km 2 (Thouret et al., 1994). The juvenile material ejected was estimated to be a volume of 25 million m3.

The initial eruption originated from a dacitic magma body, while repeated upwelling of more mafic (from Mg/Fe) magmas led to magma mixing and subsequent eruption of Andesites (tephra analysis showed 60-64 wt% silica content). This repeated recharge of juvenile magma, together with interaction of ground water and magma, was the basis for the sustained activity of very explosive nature. (M-C. Gerbe, J-C. Thouret, 2004)

In this series of vulcanian eruptions (1990-1998), ash falling onto the ice fields of Nevado Hualca Hualca (just north of Sabancaya volcano) melted the ice and produced small lahars that flowed toward the town of Maca near the Rio Colca Valley. This brought to attention the need to evaluate potential hazards from an eruption of Sabancaya in connection with the other volcanoes of the Ampato group, concerning snow and ice fields, drainage channels, and volcanic products. The greatest area of ice and snow is located atop Hualca Hualca, and she has the only drainages that flow to the north into the Rio Colca Valley. Melt water from atop Sabancaya and Ampato would flow south into the Rio Sihuas Valley. (A. Rankin, 2012).

The seismic and volcanic activity observed at and around Sabancaya indicated that its magma chamber is small in volume. The eruptions were fed from NE-SW oriented conduits in the region E of Hualca Hualca (or 10 km from Sabancaya), and the observed superficial deformation was caused by magma movement toward Sabancaya from there. (Antayhua et al., 2001). Sabancaya’s magma chamber may be located 8 km NNE of its summit at a depth of 8-18 km b.s.l. (Pritchard and Simmons, 2004)

An ash-rich vulcanian eruption plume, viewed from the SE, rises above Sabancaya volcano in northern Perú on April 15, 1991. Strong vulcanian explosions were observed at intervals of 20-30 minutes during an April 13-19 visit to the volcano. The explosions lasted about a minute and produced 3-4 km high ash clouds. Explosive activity at Sabancaya began in May 1990 and was continuing in 1995. Photo by Pierre Vetsch, 1991.

An ash-rich vulcanian eruption plume, viewed from the SE, rises above Sabancaya volcano in northern Perú on April 15, 1991. Strong vulcanian explosions were observed at intervals of 20-30 minutes during an April 13-19 visit to the volcano. The explosions lasted about a minute and produced 3-4 km high ash clouds. Explosive activity at Sabancaya began in May 1990 and was continuing in 1995. Photo by Pierre Vetsch, 1991.


On 22./23. Febr. 2013 an orange alert was called for Sabancaya, as an earthquake swarm of abt. 550 quakes was seen by the scientists as the possible beginning of a new eruptive episode. Some of the quakes were strong enough to destroy walls and bridges of the Majes Canal, an important regional water supply that depends mainly on the meltwaters from the glaciers.

The latest unrest started on 13 Aug. 2014 and is still ongoing. In Sept./Oct. 2014 pilots reported ash emissions from Sabancaya which were probably very small, as they could not be confirmed on satellite images. (GVP)

Video: A group of volcanological specialists from IGP visited Crater Sabancaya on 03 and 06 Nov.2014. In this inspection, staff observed the intense emission of magmatic gases at the crater, indicating that magmatic fluids are constantly moving within the volcano.

RISKS in case of an eruption proper

In an IGP report he investigator called to pay special attention to the care of the Majes Canal aqueduct that supplies around 20 thousand hectares of crops and that, if damaged, would deprive water to more than 100,000 residents of El Pedregal-Majes. Macedo Sanchez recalled that in the previous eruptive period of Sabancaya (1990-1998), this important channel was in danger of being damaged by heavy lahars (mudflows) in the sector Pinchollo, so it was necessary to consider it in this scenario. (IGP, 2014-08-12)

Screenshot taken from a recent IGP video

Screenshot taken from a recent IGP video

Majes Canal: Through a system of 88 km of tunnels and 13 km of canals, melt- and rain water from the Colca River reaches the plains of Majes. (Photo: INADE)

Majes Canal: Through a system of 88 km of tunnels and 13 km of canals, melt- and rain water from the Colca River reaches the plains of Majes. (Photo: INADE)

More Ellbow Grease to Them!
“Here as in other Andean areas, clashes between local, often ritualized, systems of water distribution and the centralized monetary model adopted by the state led to cases of direct “peasant resistance” by indigenous communities in the highlands. They disputed the state’s control over their water and refused to alter traditional irrigation practices. One case occurred in response to the construction of the Majes Canal, a major internationally financed development project built in the late 1970s, which channels water from the highlands to the desert and coastal areas, and which was constructed on land inhabited by thousands of people. The community of Cabanaconde originally tolerated the disruption caused by the project because they had been promised an off-take of water from the canal and subsequently an increase in irrigated land. When these promises repeatedly failed to materialize despite consistent imploring of the local authorities, the community took matters into their own hands and drilled an unauthorized hole in the canal. They collectively stood their ground and in the end were officially granted an off-take from the canal.”


To the east and northeast of the Colca River canyon, many inhabited locations would be affected to varying degrees by the emission of lava, ash scattering, ejected incandescent rocks, pyroclastic flows and acid rain, all of them dangerous to crops and people. Much like many Andean volcanoes, the largest threat from Sabancaya would be explosive eruptions that produce pyroclastic flows – but lahars and other debris flows moving up to 30 km down into the surroundings would also be significant hazards. The 1991 eruption of Sabancaya did produce a number of lahars and landslides that resulted in 20 casualties. Over 15,000 people live in villages around the volcano and 250 families living in Maca might need to be evacuated if the unrest continues as they live only ~13 km from the volcano. (E. Klemetti) During an 1988 eruption, cattle died in nearby areas either directly from poisonous volcanic gases or from eating contaminated vegetation. Another unwelcome effect of Sabancaya eruptions would be the melting of glacier caps of the surrounding mountains. The 1990 eruption layed an ash blanket over 250 square km, which has already caused rapid melting of the glaciers. This would lead to droughts and shortage of household and irrigation water in the lower regions of the area.

Agricultural terraces cling to steep slopes high on mountain flanks, and gravity irrigation systems are carved into the steep, harsh, arid mountain terrain, channeling glacial meltwater to fields far below. Photo Morail, Flickr

Agricultural terraces cling to steep slopes high on mountain flanks, and gravity irrigation systems are carved into the steep, harsh, arid mountain terrain, channeling glacial meltwater to fields far below. Photo Morail, Flickr


There are many places in the area where hydrothermal activity plays a role in daily life. The most commonly used are hot spring pools and bath huts, where the waters have high contents of sulfur and iron, and flow from the interior of the hills at a temperature of 80ºC. In addition to this, a little geyser can just as well jump up on the mountain side as you are walking past.  One of the most important geysers of the canyon is known as “Infiernillo”, or “Devil’s Shower,” located at the foot of Mount Hualca Hualca at 4250 m. Here, small “volcanoes” can be seen that eject streams of hot water, with craters of all sizes.  The largest have a diameter of up to 60 cm, and there are smaller geysers where you can cook eggs in less than 10 minutes. All the geysers emit steam and water that boils at 80 º C.


Condor  Photo: abehm.de, Wikipedia

Condor Photo: abehm.de, Wikipedia

No article about Sabancaya and the land it belongs to would be complete without mentioning THE two species of animals that catch the attention of every visitor to the area. The Colca Canyon is one of the sites recognized worldwide as the condor’s habitat, where you can observe the flight of this magnificent bird. The Condor has no larynx and therefore doesn’t make sounds or sing as do other species of birds. Its imposing presence, longevity, and ability to glide for hours were a source of inspiration in primary Andean arts such as cave paintings, ceramics, and sculptures, making this bird an icon within the religious and spiritual beliefs of Andean peoples. –

All four kinds of these loveable camel-sheep (or sheepy camels?) can be found in this National Reserve: Lamas, Alpacas, Vicuñas and Guanacos.




Sorry for going on with this, but I find it fascinating… On the summit next to Sabancaya, Ampato, the most famous mummy has been found by archeologists, frozen in time – a twelve-year-old Inca girl which they named Juanita. It was uncovered after the heat of Sabancaya’s eruptions had partially melted the otherwise almost permanent snow and ice cap there.

Juanita the mummy; an Incan sacrificial offering discovered on Ampato volcano in 1995 by archaeologist Johan Reinhard after the eruption of Sabanacaya Volcano. Photo: Museo Santuario de Altura del Sur Andino, Arequipa

Juanita the mummy; an Incan sacrificial offering discovered on Ampato volcano in 1995 by archaeologist Johan Reinhard after the eruption of Sabanacaya Volcano. Photo: Museo Santuario de Altura del Sur Andino, Arequipa


“…The archeologists also found nineteen types of plants -with corn and legumes standing out- and dried llama meat (charqui), which made them think that the girl, was a young ‘Aclla’, a maid that belonged to the Inca that would have been offered in sacrifice to the god Wiracocha to appease the volcano activity in the area. Investigations determined that by the time of her death, Juanita had perfect teeth, strong bones, that she had not suffered from any kind of disease and that she died from a blow in her head. Close to the day of the offering, she was under strict fast and about 6 to 8 hours before the sacrifice was performed, she ate a meal of vegetables. Likewise, she was prepared with plants and coca leafs to numb her. – It is known that those who were chosen by the Inca for sacrifices were prepared from an early age on. This is why Juanita must have been the object of important rituals that started in her homeland and continued through her pilgrimage towards Ampato. Today, her mummified body is in the Museo Santuario de Altura del Sur Andino of the University Católica de Santa María in Arequipa.” (Roxana Guerrero) – [After imposing Catholicism on the native people] …colonial institutions controlling land tenure and resources were put into place. It is easy to imagine how precious any surviving mummies would be after the Extirpación [of the olden beliefs]. This is evident even in modern times, considering the stir that the discovery of La Momia Juanita caused when she was discovered on the heights of Ampato Volcano in 1995.


No more mummies from now on, I promise! 🙂
Enjoy!  – GRANYIA

Webcam OVI
Observatorio Vulcanológico Arequipa (dept. of IGP)
Observatorio Vulcanológico INGEMMET
Seismogram in real-time
– IGP Twitter page

Andean Volcanism: N. Hualca Hualca Volcano, S. Peru, and El Reventador Volcano, Ecuador Burkett, 2008
Role of magma mixing in the […] 1990–98 explosive activity of Nevado Sabancaya, […] (paywalled)
IGP Report 2014-08-12
Global Volcanism Program/Sabancaya
– UNESCO (-Green Cross): Water Security and Peace
– High Mountain Melt-Down: Local Perceptions of Global Warming in the Andes and Himalayas (PDF)
Mediengerechte Aufbereitung geographischer Forschungsarbeit […] in Peru… (in German)
– UCSM, Museo Santuario de Altura del Sur Andino, Arequipa
– Juanita the Ice Girl
Investigation of active Volcanoes in Southern Peru

171 thoughts on “Volcanoes of Peru 2: Nevado Sabancaya

  1. Thank you so much writing about Sabancaya. With the unrest of Chiles at Ciero Negro(sp) my interest is growing in terms of South American Volcanoes. So are the eruptions at this volcano rather small or does it vary? I’m wondering that since the magma reservior is rather small that it does not take much pressure to get Sabancaya in an active state of unrest.

    • You are welcome mike! Sabancaya did have at least one plinian eruption and at least 2 more with huge lava beds laid down, probably effusive in nature. The ones that happened in recorded history are all small VEI 1-2 (one 3, the last one). Concluding from the most recent eruption which went on for 8 (11) years, it is thought, that the big amounts of lava are a result of very long ongoing eruptions, whereby the magma in the chamber is very frequently, or constantly, replenished from the mantle. So it doesn’t really matter, what size the magma chamber is.

  2. Hello all,

    With regard to the headlights seen earlier on Vadalda seems there were two trucks and they seemed to have cleaned the Nicair Cam this was taken at 20:57z

    Lets hope they made it somewhere safe before the storm hit.

  3. “they had been promised an off-take of water from the canal and subsequently an increase in irrigated land. When these promises repeatedly failed to materialize despite consistent imploring of the local authorities, the community took matters into their own hands and drilled an unauthorized hole in the canal. They collectively stood their ground and in the end were officially granted an off-take from the canal.”

    … and when some Gothic tribes were promised food and pay by the Romans, who then failed to do so, the Goths sacked the city in retaliation. It’s a pretty common theme in History. Bust a deal at your peril.

  4. Forgive if in the end it was just splitting hairs, but I’m still grinding on the update from IMO on the 8th.

    What strikes me the most is that they seem to have abandonded the idea that scenario 2 and 3 are dependent of a large-scale subsidence of the caldera.
    I assume ( because I’ve been around too short to have experience on that matter) that IMO chooses their words for the updates carefully.
    Under that assumption, I’d say that they have reason to believe that scenario 2 and 3 are driven ( or triggered) by other forces/circumstances than the subsidence of the Bardarbunga caldera.
    Mopshell and Echo both said some true words in the previous topic in my inexperienced opinion.
    What could have changed IMO’s thoughts after reading almost 3 months the more or less same scenario’s?
    Could it be the same reason why the SO2 levels (unfortunately) have gone up again?
    Do they have new data on the lava which proves that Holuhraun is operating on a different source than the Bardarbunga “piston”?
    Besides the fact that the scenario’s are merely possibilities and not guarantees, it seems quite clear that IMO expects that this eruption is anything but declining.
    Big question ( at least for me) remains:
    Why this sudden change?

    • I would guess that while the possibilities are still the same as ever, the probabilities of various events actually coming to be have shifted over the stretched out course of the ongoing Holuhraun eruption.

      While it may have been widely held that there is an infusion of rising magma, at this point there is still no evidence that that’s the case. Worse, there is no real reason to simply presume that there is magma rising. Without rising magma, the system is closed. Like a huge bagpipe, the magma chamber and the filled dikes are being pressurized, pumped by the slow gravitational collapse of both the caldera and BB’s rims. Obeying Pascal’s law, pressure is relieved faster at a distant pipe. This model is supported by the steady state of the system in spite of relentless bombardment from EQ’s. From day to day, nothing much changes, except that the pressure in the bagpipe is slowly released, as measured by the decreased intensity of lava flow and gas emissions.

      I could then jump to the conclusion that the Holuhraun eruption will continue on for ever and ever unchanged, except that I know better. Eventually, Holuhraun will end. But how? Something predictable or unpredictable will happen to throw off this neat model. The second scenario of a jokulhlaup can happen at any time while the eruption continues, especially originating under the Dyngjuhals cauldrons. The third one, an eruption in or around the caldera, or elsewhere more to the west or south, becomes more likely if the feeding dike is squeezed shut by one of those mag 5+s under the southeast rim. Then the system is re-pressurized for action.

      • I think pascal;s law (a subset of fluid dynamic equations) really only applies to sealed systems in a gravitational field. Where there is flow you must also include pressure drop due to fluid friction and for long thin pipes (which any between BB & HR are) the key is the flow and the pipe geometry. I think analysis of the lava suggested a mix of virgin deep magma and somewhat more evolved magma explained the result.

        Basically its a pretty complex system and probably best not seen too simplistically.

        • Nature is complex, always in motion, always changing in unknown ways. We can’t understand nature, so we’re stuck with simple-minded mathematical models.

  5. Good Morning,

    The precipitation seems to have passed up on Holurhaun, and by the look of the lava front the “hole” must be getting close to full. How long before flowing lava reaches the river channel again?

  6. Good Moring everyone.
    Graniya. Thank you for a fascinating read. I don’t know about anyone else but the snippets of “Local” information of a human kind educates me about life in other countries where volcanoes erupt. Although sometimes they could be construed as political comments, to me, they highlight the aspects of life for people living in such challenging habitats as high altitude with the awful dangers of volcanic activity.
    Hence the importance of Juanita. When the innards of a volcano was explained as superior ,unearthly beings having a seriously bad hair day, then something had to be done to make him or her feel better. Human sacrifice being the ultimate.
    This makes holes made in an unfair government activity look simplistic. Taken together it shows the toughness and determination of the everyday people who ,against climatic and geophysical and often political odds manage to cultivate enough food to support a healthy population.
    There are many areas in South America where ancient civilisations have lost this battle.
    As ever, Volcanocafe is doing what it does best; Discover, inform, educate, discuss and entertain.
    Go with the Mummies……How amazing Juanita “survived”. The Gods have accepted her and her spirit is now truly with the immortals.

  7. Thank you Granyia! Quite interesting the terraces. Once I figure myself walking among them, I start to get an idea of the immense dimension of the system… How long would it take to traverse the area from the higher slopes to the river-?

  8. Just a comment prompted by The Tsunamis’ ponderings about the IMO’s latest report on the 8th Dec.
    The IMO does not work in isolation. There are representatives of many bodies working alongside them. Scientists from universities, governments and others are all working and collecting samples and data day in and day out. This eruption must be the most studied and sampled ever!!
    With this in mind then it is not surprising that ideas and attempts at forecasting change as this amazingly mysterious and complex volcanic activity proceeds.
    It is certainly a fine opportunity for us amateurs to try our hand at hypothesising. This is what this site is all about. Exchanging ideas and learning. However it should never be forgotten that we do not have access to all the data or even the brainpower that is collected and studied in the IMO offices and University laboratories.
    Thus if the IMO changes tack then there is a good chance that samples from the on going eruption or readings from some University equipment that is being used to test someone’s new theory, has thrown a spanner in the works of forecasting scenarios to date.
    It is not that The Iceland Met Office is trying to hide something from us or anyone else for that matter, it is simply that the IMO is carrying on with their all important task of monitoring the situation ,primarily for the safety of Iceland’s Population.
    Of course they choose words with care. Since I have been here the IMO has always publicised facts in as honest and accurate detail as possible. Local people’s livelihood and lives are dependent on their information bulletins . All these reports are from the latest data recorded by expensive monitoring devices that amazingly are freely accessible to us amateurs.
    This is not a gripe aimed at any individual it is just a reminder to all readers and visitors here of the invaluable work of the IMO staff. It is also our duty to support their requests when necessary, not to overload their site in return for our privileged free access to data.

    • I don’t think any of us feel that IMO are trying to hide anything – certainly that thought never crossed my mind. I’m fascinated by the additions and omissions in their latest reporting and how these refine our understanding of the situation as it now stands. As you so eloquently pointed out Diana, IMO is at the centre of an international collaborative effort that is multi-tasking and very dynamic.

      For the last couple of weeks, many of us have felt changes are happening in events and it’s really exciting to discover that IMO think so too! It’s also a privilege to be privy to their thoughts on the situation as it develops so it’s only to be expected that we attend to, and mull over, every word. 🙂

      • The comments from IMO give an interesting window into the workings of science when faced with practical challenges. Their thoughts and words are not as scattered as ours are. Their public statements are a conferenced compromise between various reasoned, yet divergent opinions tempered by what they think the public can understand.

        • Bárðarbunga is certainly providing everyone with practical challenges! 😀 That’s why I described the situation as dynamic. With so much incoming information, not just from IMO’s equipment but from meters of all kinds from universities far and wide, they must ever be refining their overview of the situation and adjusting their models which are constructed from that information.

          Theirs aren’t just jobs, they are vocations – they are on the frontline of observing and understanding Nature in the raw. It is both fascinating, pioneering and essential work. I group them with astronauts in that respect.

    • Thank you Diana, your information gives me a good insight. Exactly what I was hoping for!
      On a side note, I have tried to choose my words carefully as well. I did not mean to imply that IMO was hiding anything or was proving bad or sloppy information. My apologies, if you got that feeling. I’m very impressed with the way IMO ( and their network) share their information. In my opinion they set an example for many foreign goverments and institutes.
      Thank you once again for your reply.

      • I wholeheartedly agree; the IMO and IES do give an honest appraisal of results and scenarios, and do set an excellent example of how to distribute information. With the sheer amount of information coming in it is undoubtedly a challenging task to mesh it together and produce a working model and prediction of events.
        I am not saying that they are witholding information; I do believe they are choosing their words carefully so as not to surprise everyone (eg. by suddenly changing the scenario). Any sudden changes in their reports/predictions might, for example, be misinterpreted by some people, and lead to a lack of confidence in these institutions – which would be a terrible thing to happen – so of course *they* are being subtle about it.
        It is inevitable that as newer information/data comes in then the scenarios could change, and the previous models could require updating or even renewing, but it doesn’t make the newer reports/predictions any less accurate. I fully endorse the good work by the Icelandic institutions and authorities. I am trying to choose my words carefully!
        As Dougal would say: “Careful now!” 🙂

      • I think it’s a very reasonable question TheTsunami. IMO is not hiding information. But also: they are not publishing everything, that is not their job. Researchers interpret/evaluate their gathered data, at the end IMO translates them to scenario’s to inform Icelandic inhabitants.

        So when the chosen words in the published scenario’s change or scenario’s change, it is legitimate to ponder why the published scenario’s have changed. Obviously there are data that have caused a change in views, or there are researches that have changed their opinion as a result of ongoing insight, which is normal in the scientific world.

        • I see the changes in scenarios as marks of progress – IMO are responding to the plethora of incoming information and sharing their progress reports with us. It’s fascinating! No wonder we get so excited about it! 🙂

    • I agree, Diana. I also think there is probably nothing ‘sudden’ about the change in the IMO’s take on what is likely to happen. They are aware that people regard their updates as ‘stone tablets’ and will have put a great deal of discussion and thought into any changes they make. I think they do a great job, and I’m happy to accept what they say, watch the amazing spectacle of this eruption, and not speculate on what may or may not happen.

      Also thank you Granyia for another great post! 🙂

    • I expect that IMO staff are as excited about the events as the readers of VC. They may even read this blog to get ideas. I had the impression that some of their offerings were in response to queries made here. The main thing that has changed in their phrasings is that the risk of a major collapse of Bardarbunga is gone . That makes sense as the subsidence rate and earthquake energy has decreased, suggesting the caldera is getting close to a new equilibrium. It may either go quiet and stable at that time, or the subsidence may become linear again and earthquake activity constant, if there is a still a drain to the dyke system. We will know when it happens! A catastrophic event can never be ruled out but the chances of that seem no higher than at any other location in Iceland. Bardarbumga has been remarkably well behaved.

      To blow, or not to blow: that is the question:
      Whether ’tis nobler in the mind to suffer
      The slings and arrows of outrageous collapse,
      Or to take arms against a sea of magma,
      And by opposing end them? To die: to sleep;
      No more; and by a sleep to say we end
      The heart-ache and the thousand natural shocks

  9. Graniya very informative post Thankyou …….visited 40 countrys so far ………still to get to South America

    Intrusion triggering of the 2010 Eyjafjallajökull explosive eruption

    Gradual inflation of magma chambers often precedes eruptions at highly active volcanoes. During such eruptions, rapid deflation occurs as magma flows out and pressure is reduced1, 2, 3. Less is known about the deformation style at moderately active volcanoes, such as Eyjafjallajökull, Iceland, where an explosive summit eruption of trachyandesite beginning on 14 April 2010 caused exceptional disruption to air traffic, closing airspace over much of Europe for days.
    This eruption was preceded by an effusive flank eruption of basalt from 20 March to 12 April 2010. The 2010 eruptions are the culmination of 18 years of intermittent volcanic unrest4, 5, 6, 7, 8, 9. Here we show that deformation associated with the eruptions was unusual because it did not relate to pressure changes within a single magma chamber.
    Deformation was rapid before the first eruption (>5 mm per day after 4 March), but negligible during it. Lack of distinct co-eruptive deflation indicates that the net volume of magma drained from shallow depth during this eruption was small; rather, magma flowed from considerable depth. Before the eruption, a ~0.05 km3 magmatic intrusion grew over a period of three months, in a temporally and spatially complex manner, as revealed by GPS (Global Positioning System) geodetic measurements and interferometric analysis of satellite radar images.
    The second eruption occurred within the ice-capped caldera of the volcano, with explosivity amplified by magma–ice interaction..

    Gradual contraction of a source, distinct from the pre-eruptive inflation sources, is evident from geodetic data. Eyjafjallajökull’s behaviour can be attributed to its off-rift setting with a ‘cold’ subsurface structure and limited magma at shallow depth, as may be typical for moderately active volcanoes. Clear signs of volcanic unrest signals over years to weeks may indicate reawakening of such volcanoes, whereas immediate short-term eruption precursors may be subtle and difficult to detect

    • They measure sill formations at ~5km depth. The first flank eruption was fed from the main intrusion but a different leak. It did not lead to deflation, because the eruption rate was less than the inflow rate. The later summit eruption (30-60m^3/s) did give deflation, which they measured came from one of the sills. They are not to sure whether there was a stack of sills or a single larger one but the deflation came from a fairly extended reservoir – not just the narrow conduit.

      • nice illustration of one of my favorite eruptions! Though the view should really be a bird’s eye view to show the distinction between a sill and a dike, both being quite thin. The way it looks here, it appears like a huge wad of magma formed under Fimmvorduhalsi when it was actually just a a pretty thin dike that even got interrupted later on and probably had less total volume than the sills seen here in cross section. The dike also fed a second fissure at a strike of about 30° to the first one, which complicates the geometry a bit.
        Moreover, what stopped the feed to the surface is kind of interesting in its own right as this triggered the final eruption at the main crater. Was the interruption due to a fault shifting, thereby leading to a build up of pressure in the main conduit or did the dike find a detour to access a shallower zone of crystal mush? My guess is that the plumbing of these systems is way more complicated than most of us imagine, with zones of partial melt intersected by sills and dikes and nascent chambers forming at the interstices. But the normal intuition would be that an open flank fissure would relieve pressure on the system enough to prevent a summit eruption occurring. What is strange at Eyjafjallajökull is that the opposite happened. The vent got interrupted and pressure built until the main summit crater blew. Maybe Holuhraun / Bardabunga is going to do the same on us. That would be really strange.

        • One can guess. The flank eruption was less than the inflow (13 versus 30 m3/s) so the overpressure did not decrease from the eruption. Deflation was seen three days before the flank eruption ended. This suggest magma moving up: the pressure had become high enough to open up a pathway into a higher layer. This reduced pressure in the sill supplying the flank, flow rates in the dyke reduced. If the flow rate drops below a critical value, the magma solidified before reaching the exit (it depends on dyke width but presumably this was less than 1 meter). Two days after the flank eruption ended, the summit erupted, but I think the cause of the summit eruption was a few days earlier, and the failure of the flank eruption. In Barda, the dyke erupion is much stronger, giving net deflation in the Barda reservoir. So no eruption is likely elsewhere in the system until the present leak is plugged.

          • That ties in nicely with how IMO were scurrying around about 12 hours before the summit eruption at Eyjaf. They obviously knew something was up as they were warning the local farmers before anything happened.

            Albert, how constant is inflow into a system like this? We had a big discussion about this during the Eyjaf episode, particularly with Peter Cobbold, as it appeared like there was a definite periodicity to the waves of earthquakes, each lasting about 18 hours from memory. We developed all sorts of ideas from pulses of magma arriving at the bottom of the system to cascading failure of country rock and so on. Is it the case that melt generally enters a shallow system at a relatively steady rate?

            • If you go deep enough (mantle) everything becomes very uniform. There is a constant flow rate in the mantle convection, just as there is a stable and uniform motion of the continents. But the input of magma is specific locations fluctuates a lot. The paper above mentions several episodes: one in 1999 depositing 15 million cubic meters, one in 2005 with 25 million cubic meters. There was a new inflow in 2009 and early 2010. They mention a magma inflow at an average rate of 2–3 cubic meters per second before March, followed by an average flow rate of
              30–40 cubic meters per second, totalling 60 million cubic meters. So this is certainly not constant but more like your pulses. Remember that mantle convection is not magma: it is solid. The melt only occurs in limited regions above the mantle. The melting process can be more episodic. Over time and space it averages out: Iceland, I believe, gets about 0.9 cubic kilometer of new magma per year. Most of this stays below ground and will never erupt. But exactly when and where it appears varies a lot. The whole rift can even move by 100’s of kilometers: you can see these jumps if you look at maps of the mid ocean ridges, and it has happened underneath Iceland as well.

  10. OT:

    On stormy days like this in Iceland, I’m thinking of better “seismic” measurements then the one we have there.

    As a Space-Freak my first choice goes to the satellites, what do you see as a possibilities? Just deeper geophones for less background noise?


    P.S.: Does someone know how sensitive GOCE was? <M9 <M8 <M7 <M6? It was abel to determine the geoid with an accuracy of 1–2 cm…

    • It is probably doubtful that GOCE would have detected an atmospheric perturbation had the quake been of a different focal mechanism. Strike-slip would likely not have displaced any (or as much) air in the manner of the Tohoku quake. As it was, the quake lifted a slab of water directly up, in piston fashion, that was as great or greater in volume than the entire above sea-level volume of El Hierro. And, it did this in short order.

  11. Thank you Granyia for you very thorough reporting on the Sabancaya volcano and surrounding areas. It brings on a rush of emotions for us as our first trip to S. America in 2002 was in Peru and Bolivia. We traveled from Arequipa with our 15 yr old son to the, then, end of normally used road along the Canyon de Colca. The overviews of the many volcanoes were almost other worldly in feel.

    We walked on ancient trails passing through potato fields in fields that were put in place by the Inca people many centuries before. Some of the irrigation systems dated from the same period. Local people showed us small holes where numerous mummies had been found close to the guest house.

    I have always been interested in volcanoes and this was a visit to paradise for me. Two years ago we spent 6 weeks in the wonderful country of Colombia full of friendly people. And now after your post, we are thinking about revisiting the area in Peru again as it was so stunning. If anyone has questions about travel in these areas they can contact me.

    • Thank you Biologique, I am glad my article did that! 🙂 As you might remember, in Peru 1 I had aired that idea of going there myself. My main concern after reading up on several travel reports is that I might not take too well to the great hights one is travelling in. I read that many members of package travel groups could not take part in all that was offered for being unwell with headaches and nausea, and that people like me (61) should consult their GPs before travelling. What is your experience with hights of 3-4000m?

      • Hi Granyia, at the time we went to Peru I was 62 yo and had no problems with the altitude. My wife who is younger than me and handicapped (polio) would walk with canes without problem. Perhaps we would experience a bit of light headiness if exerting. Interestingly, our 15 yo son had problems on this trip, two times, with mild altitude sickness. A guard in a museum near Lake Titicaca said that the young are often most affected with altitude sickness and recommended mate de coca for him. A tiny food stall near the museum had some and soon after drinking it he felt better. Mate de coca is simply an effusion of coca leaves and has essentially no traces of cocaine.

        In later years I found the tea effective in staving off muscle cramps. While in Colombia two years ago I went on a 5 day trek in the Sierra Nevada de Santa Marta to the Ciudad Perdida (lost city) and the first night had severe leg cramps. The trip was moderately challenging in several places and the jungle was hot and humid. I arranged with the guide to get coca leaves from the local indigenous and when taking several cups of mate de coca in the evening, I had no problem with cramps for the rest of the trip.

        I would definitely check with your doctor if you have breathing or heart problems. I hope this helps you.

  12. Vala seems to be caught in a time warp at around 22:00 last night. Fortunately, the drumplots are rolling along happily so we can see the action there. It’s suspiciously quiet around Bardy… an M5 due later today I’m thinking…

    • Thanks Renato – good read and summary of the situation.

      It seems like it’s difficult to expect what will happen there. I don’t think we’ll see an eruption particularly soon since we would see much much higher volumes of earthquakes prior to an eruption. As a comparison, they call 200 earthquakes in a month a significant swarm. In Colombia, Chiles and Cerro Negro have had multiple days of over 4000 earthquakes within a single day, and that volcanic complex has also been quaking with strong swarms for well over a year at this point.

      I would presume that any eruption that would occur here wouldn’t be a big caldera eruption, but would likely be a highly explosive Rhyodacitic eruption ranging from VEI-4 to VEI-6 (based off previous post-caldera output) but that’s entirely just speculation.

      The good thing about Maule, or any of the huge caldera complexes in the high Andes is that they’re very remote, making potential life and property damage very minimal until it would likely get into the VEI-7 range, which is still somewhat unlikely (but can’t be ruled out).

    • My little niece (5 at the time) said of the Swiss mummy: yes, it’s not pretty, but very interesting. I was trying to page past that specific article in the Nat. Geographic magazine. An accusing finger turned back the page and pointed at the bold print: ‘And you have not read all it says!’

      • “And you have not read all it says”

        It sounds to me like she is parroting a rule that she has been taught. Perchance “Read it all, then decide?” (if so, it’s a good lesson that reinforces critical thinking.)

        • 🙂 She is a master at critical thinking. Said last week that people should do like the brown forest butterflies: spiral upwards in a flutter to a branch to perch on to contemplate the confrontational situation before one moves on without wasting time fighting or killing the other. (She is 7 now.) I had to give her pictures of the eruption for ‘show and tell’ in the classroom where she explained how new earth is born. Yes, she knows about the tectonic plates.

          • Good heavens, Aunty hen! She’s an absolute treasure! I hope the schools she attends have a gifted program so she can progress at her own rate. I wonder what vocation she will choose? She could do anything! 🙂

            • 🙂 At 3 years old I asked her if she was feeling tired. With drooping eyes she replied totally seriously: ‘My time does not wait.’ I know I am the doting aunty, but the teacher told me she had never had a child like her. So… let’s hope life gives her room. 🙂 I’ll stop now.

          • Hen, I think that your niece is a very lucky girl to have an aunt like you who is so interested in her.
            On another subject – how are you coping with the ‘load shedding’? Trying to run a business with all
            these black outs is sooooooo frustrating!

            • A pain in the …
              It impacts on many so widely — all because of a few idiots blind with greed a few years ago. Sigh. What an extra nightmare for people with businesses. Traffic in a big city is a horror. 🙂 I’ll stop here, else this will become really nasty.

  13. I am looking for the page “http://platformsthatwork.com/bardies/quakesonaplane.php” It seems to be gone.
    The site was very informative. Has somebody access to it?

    • The page is gone. Its owner seems to have disappeared. His email bounces, his Google+ account is gone and his twitter account is no more.Last I heard, nobody has any clue what happened. … Carr, if you read this, I am worried about you and I hope everything is OK.

      • I really liked that site and just noticed its not working. Is there another site that has similar near real time information?

  14. Strong hurricane wind gusts confirmed in the West Fjords of Iceland up to 202km/h. One equipment also measured up to 300km/h but it’s probably not a reliable measurement, it’s also high on the mountains. Sustained winds are around 120km/h.

    On another side, I also see an interesting development, but per se it’s not yet nothing, but worth to keep an eye: a small swarm of quakes located SW of Bardarbunga caldera. Could a new dike be developing in that direction? Hopefully not.

      • By the way, Cape Verde authorities are now preparing for worst scenario and preparing for evacuation of next populations. They think they still have some days untill lava stream arrives.

        • Thanks Louis for keeping us reminded of the situation on Fogo! I find that much more important than BB (for the time being), pity that there are no monitoring possibilities online. I wanted to say “much more interesting” but, in the light of all the pain and sorrow this volcano is creating, interesting might not be the best word to use…

  15. Really burning bright, our tiger in the night (Mila2).
    Seeing the pictures of the Cape Verde people evacuating their homes is really sad.

  16. Severe weather starting here….This wind will test my husband’s expertise at erecting a DIY car port under which he can work on our VW camper restoration. I hope my greenhouse remains intact too :(.
    It’s funny though as I remember violent storms as a child at this time of year with raging seas and bitter winds. Nowadays with the internet, people here seem to think this weather is freaky. I am sorry, but unpleasant as this weather is, this is Britain and this is the start of a British winter, I do not expect to be able to dress in summer clothing or eat breakfast Al fresco for another four or five months!

    • Diana –
      Southern Oregon Coastal weather is much like that, too . Northern California is getting a good-old fashioned pacific Sou’Wester. People there say the same thing, but if one has been around longer than most of my socks,
      and live in areas like Britain or Oregon, (which are very similar in land area
      and west of the Cascades, climate), It is the way the weather is. Nothing unusual..

    • Dianam it was a hell of a storm here, and it still is.

      Wind gusts were up to 202 km/h, and there was even a station that recorded 300km/h but i don’t believe in such measurement, but it shows well how crazy weather was, with snow blizzard ice of course.

  17. I’ll think of you all in the winds, and they bring back memories of our own fake “hurricane” back in 1987 here in the South East UK. A scary night and an amazing day thereafter. The main road near our house was invisible under downed trees and branches and needed a bulldozer to clear it. And the smeared mess over the windows on buldings, assumed to be a mix of pulped foliage and sea spume 40 miles from the sea. Keep safe!

    • Typical news hype here in UK, I lived in the outer Hebrides for years and have many friends there. These are the same as usual winds, yes they’re strong but not unusual. Power went back on over an hour and a half ago in breasclete on the isle of lewis.

      Iceland has had it real bad and that never gets a mention here. Its probably same as usual there too, as my dad used to say ‘a lot of weather we’ve been having lately”….

      • I think “weather bomb” was over the top. The winds weren’t even as strong (in the UK) as the storms last winter. How quick the media forgets. Much was made of 50 foot waves, yet in Cornwall, they were breaking over cliffs last year. I’d hate to think what they’d be saying if it was as bad here as in Iceland.

    • not so good scrubber design. The green thingy is not full of water.
      it would be better to cut some small pvc pipe to provide more contact area and to use a fish tank pump (much quieter to spray the water in the enclosureand recirculate it).
      A PC ventilator would do the trick to inject polluted air in the water spray( use a shower head)

  18. I would like to add something to the mantle discussion. – As it seems, mantle is one of the last frontiers in geology. Consequently, there are many theories about it. Two major ones are plate vs. plume mantle…..
    For example, this site is devoted to plume magmatism in very many different ways:
    There are articles about mantle, hotspot, locations, theories, graphs,…
    The following is also good, and not too long:
    There are some unknowns regarding the studying of mantle, one is that we do not have a clue about how pressure changes behavior of minerals or magma. There are other factors too.
    Probably one of them is scale, yet again; even the question what is fluid, or solid, may become problematic in the mantle. Does solid flow? If rock flows, is it solid? What time scale should you use to determine if flow is present? A minute, a day, a century, a million years?
    Just some general questions to throw, and remind us how little we are really. On the other hand, for a fruit fly, we are enormous and seem to live for ever…

  19. December 5, eruption flight to Holuhraun taken by pilot Guðmundur Þ. Vilhelmsson

    • Fantastic insulating powers of the lava. Snow just feet sway from the crater lip.

      Mila1/2 completely blank – I suppose the storm has arrived.

  20. 100 days of continuous eruptive activity in Holuhraun

    Click to access bb100days_ens.pdf

    The earthquake sequence associated with the magma movements and volcanic activity at Bárðarbunga
    differs greatly from all volcanic earthquake swarms that have been observed in Iceland since the
    beginning of seismic measurements. Summing up the energy release of all earthquakes detected so far
    reveals a corresponding magnitude of 6.6 if the same energy was released in one big earthquake.

    This number might sound small, however it has to be kept in mind that the magnitude scale of earthquakes
    is logarithmic. An increase of one magnitude corresponds to an energy increase by a factor of around 30,
    i.e. a magnitude 5 earthquake releases around 30 times more energy than a magnitude 4. It is however
    worth to notice that a tectonic earthquake like the 1912 earthquake in the eastern South Icelandic Seismic
    Zone or 1963 in Skagafjörður (both were around magnitude 7) can easily outnumber the recent activity
    around Bárðarbunga in just one event, by means of moment release.

    The cumulative moment release during the migration of the dyke intrusion between 16 August and 1
    September corresponds to a single earthquake of about magnitude 6.0. In contrast, the whole moment
    released in the earthquake swarm prior to the Eyjafjallajökull eruptions in 2010 hardly reached magnitude
    5. However, a direct comparison of both swarms is impossible as the length of the present dyke is also
    significantly larger than in 2010. The activity on the Bárðarbunga caldera rim remains unprecedented as
    it is the first opportunity ever to follow a caldera subsidence in Iceland with modern scientific
    measurements and methods.

    GPS measurements
    Great crustal movement was detected while the intrusive dike was being formed. The GPS measurements
    showed the advance of the intrusion and, simultaneously, subsidence towards the center of Bárðarbunga.
    Models based on GPS and on InSAR images from satellites indicate that the volume of the magma in the
    intrusion is about 0.5 cubic kilometers and that it was fully formed, already in the beginning stages of the eruption.

    Horizontal spreading across the dike on a 25 km stretch between Urðarháls and Kverkfjöll
    measured 1.3 m maximum. But InSAR measurements indicate that the spreading next to the dike is
    considerably larger. Since the onset of the eruption the subsidence has been continuous, however slightly
    diminishing, towards Bárðarbunga. Tectonic movement during the seismic events in Bárðarbunga which
    began in the middle of August 2014, are the greatest which have been detected in Iceland since the Krafla
    volcanic events in the seventees and eightees.

    Gas measurements

    The ongoing eruption at Holuhraun is very rich in gas. We should go 150 years back to find an event
    (Trolladyngja) that had a comparable impact on Iceland and its inhabitants, in terms of enviromental and
    health issues.
    IMO is monitoring gas releases from Holuhraun using DOAS and FTIR instruments for the estimation
    of SO2 flux and amount of other components in the volcanic cloud. The more abundant gases present are
    SO2, CO2, HCl, HF, H2O.
    In the first month and half we had an averaged flux equals to 400 kg/s (~35 kT/d) with peaks up to 1300
    kg/s (~112 kT/d). Assuming a constant release of gas until today, the eruption has injected into the
    atmosphere an amount of SO2 in the range 3.5 Mt (considering the average flux) – 11.2 Mt (considering
    the peak).
    These numbers could be compared with the largest gas-rich eruption occurred in Iceland in 1783-1784
    (Laki eruption) and lasted 8 months. It has been estimated that during that eruption up to 122 Mt of SO2
    were released into the atmosphere. Assuming a constant gas flux during the 8 months, the Laki eruption
    injected ~51 Mt in 100 days (5 – 15 times the Holuhraun‘s amount).

    BB caldera total quakes >M5+__#74………..M4.0-4.9__#453……..M3.0-3.9__# 721……..checked ~7000
    the energy release of all earthquakes detected so far…..magnitude of 6.6 if the same energy was released in one big earthquake & during the migration of the dyke intrusion a single earthquake of about magnitude 6.0
    M6.6 = 8,000,000 TNT equ…..Total
    M6.0 = 1,000,000 TNT equ…..Dyke
    ~M6.55 = ~7,000,000 TNT equ……at BB caldera
    so BB’s gotta be …”well & trully fractured & smashed up”

  21. On Twitter, there is “something” from PVMBG-CVGHM (Indonesia) titled in translation: “Merapi: Lava, Lava, Sheep & Sands Mine” but if I click on the link, it tells me I am not entitled to view it… hmm, I don’t have a Twitter account. Could somebody who has access, give us an account please on what this is about? The link is: https://t.co/LxxuY61tFC Thanks!

  22. Fogo: Destruction of houses 2014 in Cha das Caldeiras, Portela (Cape Verde Fogo island), in the second half of this video you see the lava destroying a house completely. (06-12-2014)

  23. About 168 years ago, a group of pioneers on their way to California, became stranded in the mountains when the snows came early. They were later known as the Donner party. This region of the mountains is prone to beyond wicked snow storms, and the phenomena has described as “Storm King.” Though its not an early snow, the chance of a mondo event there are starting to fall into place.

    California Storm: High Wind Warnings, Flood Watches, Blizzard Warnings Issued for West Coast Storm

    Over the next few days, you can check out Truckee and the Donner pass area on webcams.


    And a video about an archaeological dig of the site.

    And one of the researchers discusses some of the data derived from that dig. Of note, the “Graves-Reed” cabin is believed to have been at the location of the current agricultural inspection station on Interstate 80.

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