Explosive eruption at Galeras 30 September 2009
Posted by admin in activity reports, Colombia, eruptions, Galeras.Tags: Colombia, Galeras, South America, volcanic activity reports, volcanic eruptions
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Galeras volcano in Colombia erupted explosively at 09:14 local time today, and is currently on the highest alert level of Red, ‘eruption imminent or under way’. There are no reports of deaths or injuries. INGEOMINAS Observatorio Vulcanológico y Sismológico de Pasto issued an extraordinary bulletin on the eruption at 12:20 local time today, which reports:
- The explosive event occurred at 09:14. National Parks personnel nearby ‘reported two explosions and the emission of incandescent material in the sector of the active cone’.
- The eruption generated a column of ash which reached approximately 8 km above the summit, and was initially deflected to the east and later towards the north. ‘Measurements of sulphur dioxide taken between 09:30 and 10:00 showed high values of between 1100 and 9300 tonnes/day’.
- Washington VAAC ‘estimated a height for the emission column of about 11 km. Satellite images showed that in the first minutes the column dispersed in a north-western direction and later the winds shifted it to the north’. Ashfall has been reported in Sandoná, Ancuya, Linares, La Llanada and Sotomayor.
- The energy levels of today’s eruption were similar to those of the 7 June 2009 eruption, and roughly one third of the energy of the 20 February 2009 eruption.
Following the eruption, seismicity has fallen to a low level. INGEOMINAS is continuing to watch the volcano closely.
For all our Galeras coverage: Galeras « The Volcanism Blog.
Information
Global Volcanism Program – Galeras – summary information for Galeras (1501-08=)
Portal Corporativo de INGEOMINAS – Instituto Colombiano de Geología y Minería
Observatorio Vulcanológico y Sismológico de Pasto – Pasto volcanological observatory main page
SI/USGS Weekly Volcanic Activity Report 23-29 September 2009 30 September 2009
Posted by admin in activity reports, Alaska, Batu Tara, Chaitén, Chile, Costa Rica, Dieng Volcanic Complex, Dukono, eruptions, Hawaii, Indonesia, Japan, Kamchatka, Karymsky, Kilauea, Papua New Guinea, Rabaul, Redoubt, Russia, Sakura-jima, Shiveluch, Turrialba, United States, Weekly Volcanic Activity Reports.Tags: Global Volcanism Program, volcanic activity reports, volcanic eruptions
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Click on the map for a larger version (1280 x 898 pixels).
The Smithsonian Institution/United States Geological Survey Weekly Volcanic Activity Report for 23-29 September 2009 is available on the Global Volcanism Program website. The following is a summary and not a substitute for the full report.
- The current report: Weekly Volcanic Activity Report.
- Previous reports: Weekly Reports Archive.
- The SI/USGS map of volcanoes discussed this week.
New activity/unrest: Dieng Volcanic Complex (Indonesia), Karymsky (Russia), Shiveluch (Russia).
Ongoing activity: Batu Tara (Indonesia), Chaitén (Chile), Dukono (Indonesia), Kilauea (Hawaii, USA), Langila (Papua New Guinea), Rabaul (Papua New Guinea), Redoubt (Alaska, USA), Sakura-jima (Japan), Turrialba (Costa Rica).
Pacific volcano offers glimpse of acidic ocean 30 September 2009
Posted by admin in volcanoes.Tags: Mariana Islands, Maug Islands, ocean acidification
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The eco-nightmare of choice for an increasing number of people today is ocean acidification. In the north-west Pacific Ocean, underwater vents within the submerged caldera that forms the Maug Islands emit carbon dioxide into a tropical shallow-water environment, creating a localized level of acidity that is fatal to marine life. The Smithsonian Magazine has an article all about the resulting ‘death zone’:
The unique death zone, where the water is so acidic from the volcanic vents that no coral can survive, is only 30 feet across and 200 feet long … Both the death zone and the transition zone, where highly acidic water merges with normal sea water, should yield insights into how corals will react to a changing ocean.
A swim through the ocean’s future – Smithsonian Magazine, 17 September 2009
Earthquakes at Apoyeque volcano, Nicaragua 30 September 2009
Posted by admin in activity reports, Nicaragua.Tags: Apoyeque, Nicaragua, volcanic activity reports
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There has been a flurry of earthquakes under Apoyeque volcano in central western Nicaragua. The Instituto Nicaragüense de Estudios Territoriales (INETER) seismic monitor lists eight earthquakes since 20:00 local time on 29 September (03:00 GMT 30 September), with magnitudes varying between 1.6 and 3.1. No property damage has been caused, and there have been no injuries.
Javier Mejía, INETER subdirector, is quoted in La Prensa as calling the activity ‘normal for a volcano such as Apoyeque’. Seismic swarms occurred at Apoyeque in 2001 and 2007, with the 2001 swarm including quakes up to magnitude 5.2.
News
Apoyeque produce sismos – La Prensa, 30 September 2009
Information
Global Volcanism Program: Apoyeque – summary information for Apoyeque (1404-091)
Instituto Nicaragüense de Estudios Territoriales – INETER main page
Mexico marks Jorullo’s 250th birthday 30 September 2009
Posted by admin in anniversaries, Mexico.Tags: Jorullo, Mexico, Michoacán, Paricutín
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Mexico has been marking the 250th anniversary of the appearance of Jorullo volcano, a cinder cone in the Michoacán-Guanajuato volcanic field situated in the southern state of Michoacán. The eruption which produced Jorullo began on 29 September 1759 and continued for 15 years, with lava flows, ashfall and mudflows affecting the surrounding landscape. By the end of the eruption the cone had reached a height of 1320 metres, with a 400-metre-wide crater 150 metres deep, and Jorullo’s lava flows had covered 9 square kilometres around the volcano.
A number of events will be taking place in Mexico to mark the anniversary, including a conference organized by the Universidad Nacional Autónoma de México. Scientist Víctor Huco Garduño Monroy of the Universidad Michoacana de San Nicolás de Hidalgo (UMSNH) has taken the opportunity of the anniversary to warn of the continuing dangers posed by volcanic activity in Michoacán:
Michoacán is located in an area of ‘high risk’ in terms of earthquakes and volcanic activity, as recorded in just over one thousand volcanic cones on the meseta purépecha, which has the potential to give rise to new volcanoes. However, there is as yet no state seismological network, nor any regional seismological or geological monitoring … There is a high rate of the emergence of new volcanoes that could in future give us a scenario like that of Paricutín or Jorullo.
The emergence of Paricutín in 1943 was the most recent eruptive activity in the
Michoacán volcanic field. Paricutín, like Jorullo, appeared from nowhere, gradually building into a cone 424 metres high and swallowing two villages and a large area of farmland before the eruption ceased in 1952. It is certain that the future will see similar eruptions in Michoacán – new Paricutíns, and new Jorullos.
News
Conmemorarán la aparición del Jorullo, el volcán más importante de Michoacán – Cambio de Michoacán, 28 September 2009
Inician festejos de aniversario del Nacimiento del Volcán El Jorullo – Quadratin, 28 September 2009
Michoacán, territorio de ‘alto peligro’ por la actividad volcánica y sísmica – La Jornada Michoacán, 29 September 2009
Redoubt back to Green/Normal 30 September 2009
Posted by admin in activity reports, Alaska, eruptions, Redoubt, United States.Tags: Alaska, Redoubt, United States, volcanic activity reports, volcanic eruptions
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The Alaska Volcano Observatory lowered Redoubt’s status to Aviation Colour Code Green and Volcano Alert Code Normal at 18:44 GMT (10:44 AKDT) yesterday, 29 September 2009. According to the Volcanic Activity Notice issued by the AVO …
Over the past several months, seismic activity, volcanic gas output, ground deformation, lava dome temperatures, and outward signs of lava dome instability at Redoubt Volcano have been declining. The volcano appears to have returned to its normal background condition and for now poses no immediate threat of eruptive activity. Accordingly, AVO is lowering the Aviation Color Code to GREEN and the Volcano Alert Code to NORMAL.
The AVO notes that the Redoubt lava dome has reached a volume of approximately 70 million cubic metres, and that lava domes on steep slopes are ‘typically unstable’. However, given that 60 days have passed since the dome ceased to grow, ‘AVO believes the possibility for dome collapse is small and declining toward a background level of danger typical of many active stratovolcanoes with steep unstable rock slopes’. Local hazards remain, associated with the hot lava dome: gas emission, abundant steaming, rockfalls, but these do not pose a significant hazard beyond the summit area of the volcano.
With Redoubt now at Green/Normal, only Shishaldin among the AVO’s charges remains at Yellow/Advisory, because of its sustained but low-level seismic rumblings.
For all our Redoubt coverage: Redoubt « The Volcanism Blog.
Information
Global Volcanism Program: Redoubt – summary information for Redoubt (1103-03-)
Alaska Volcano Observatory – Redoubt – AVO information and updates for Redoubt
Alaska Volcano Observatory – main page for the AVO
Tephra not good for the teeth 29 September 2009
Posted by admin in calderas, current research, Germany, Laacher See, natural hazards.Tags: Eifel volcanic zone, Germany, Laacher See, volcano research, volcanoes and human society
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Are supervolcanoes bad for your teeth? Those of us who grind our teeth whenever slapdash science journalists throw the word ‘supervolcano’ into any story connected with a large-ish volcanic eruption have certainly found this to be so (take a bow, Discovery Channel). However, take out the spurious supervolcano angle and there is a serious scientific story here* about the mechanisms through which volcanic activity directly affects the material basis of human existence.
The Laacher See eruption was a significant volcanic eruption that took place in the Eifel volcanic zone in what is now western Germany around 13,000 years ago. The eruption plume may have reached 20 km altitude and the volume of material ejected was around 6.3 cubic km (source), which on the Volcanic Explosivity Index makes it a VEI=5 or 6. The resulting caldera, filled with water to form a rather lovely lake, is now known as the Laacher See. This eruption, it has been argued, had wide-ranging effects on contemporary human societies, causing large-scale depopulation and migration, disrupting and bringing to an end some cultures and leading to the creation of others.
The eruption covered a vast area with pulverized volcanic debris – the Laacher See Tephra. The tephra reached as far as southern Scandinavia and northern Italy: it has been traced up to 1100 km north, 600 km south, and 100 km southwest of the Laacher See caldera. This very fine and highly abrasive material would have covered everything, making any food consumed by animals and people in affected areas into a form of unpleasant and unhealthy sandpaper. An article in the October 2009 Journal of Archaeological Science (link to abstract at ScienceDirect) by Felix Riede of Aarhus University and Jeffrey M. Wheeler of the University of Cambridge investigates the issue of tephra as a dental abrasive:
Our results show that the Laacher See tephra contained particles roughly twice as hard as even the hardest portions of any of the teeth investigated. We also suggest that fluoride-induced weakening of dental enamel may have further aggravated tooth wear. These mechanisms may have acted in concert to produce elevated levels of, in particular, animal mortality, which in turn may have led to an abandonment of the affected landscapes.
The article suggests that the tephra may have continued to affect the landscape for as much as 300 years after the eruption. Interestingly, recent research based on studies of the current Chaitén eruption suggests that the impact of ashfall from past eruptions has been significantly underestimated, so tephra deposited by eruptions such as Laacher See may have spread wider, and endured for longer, than has been previously thought.
Parts of the Eifel volcanic zone have been active in the very recent past (geologically speaking: less than 10,000 years ago). Current activity at Laacher See itself, says Hans-Ulrich Schmincke’s Volcanism, is marked by ‘a strongly CO2-bubbling area about 200 m long along the east shore … The composition of these gases is magmatic and closely resembles those of Lake Nyos’, and ‘The area around the Laacher See basin is characterized by elevated microseismic activity’ (p. 207). Schmincke regards the Laacher See volcano as dormant, not extinct.
P.S. Dr Klemetti has posted about Laacher See and its abrasive tephra at Eruptions, and has accumulated some very interesting comments on the topic.
* To be fair, the Discovery Channel has quite a decent news report on the Laacher See Tephra research. Just try to ignore the two instances, one being in the title, of that word ‘supervolcano’, and the accompanying picture of a volcano utterly unrelated to the story being reported.
The eruption of Chaitén, at the NASA Earth Observatory 28 September 2009
Posted by admin in activity reports, Chaitén, Chile, eruptions, NASA Earth Observatory.Tags: Chaitén, Chile, NASA Earth Observatory, South America, volcanic activity reports, volcanic eruptions
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There is a wonderful new image of the ongoing eruption of Chaitén volcano at the NASA Earth Observatory website today. This natural colour image (reduced size version above) was captured by the Advanced Land Imager (ALI) aboard the NASA/USGS Earth Observing-1 (EO-1) satellite on 27 September 2009. The full image (2 MB, 2683 x 2683 pixels) from which the reduced picture above is a detail is quite magnificent:
The detail below taken from the large image shows the caldera, which is now almost entirely filled by the constantly-growing lava dome. The area of active growth can be seen in the west (towards the left of the image); this area is steaming vigorously, and the very steep slopes of the dome complex can clearly be seen, particularly towards the south. These steep slopes are unstable, producing constant rockfalls. A large-scale collapse here would send debris flows down the valley of the Chaitén river towards the town of Chaitén, 10 km south of the volcano.
A further detail view shows the town of Chaitén, engulfed in volcanic deposits which have descended the Chaitén river valley from the volcano in the form of volcanic mudflows or lahars. A fan-shaped bank of accumulated volcanic sediment, washed out of the river estuary, cuts the town’s harbour off from the sea.
[NASA image by Robert Simmon, using EO-1 ALI data provided courtesy of the NASA EO-1 team. Thanks to Robert Simmon of the NASA Earth Observatory for giving the Volcanism Blog a preview of this image, and for referencing this blog in his caption.]
Ash and steam plume from Chaitén – NASA Earth Observatory (28 September 2009)
For all our Chaitén coverage: Chaitén « The Volcanism Blog.
New Australian volcano may pop up in Ballarat area, warns geologist 28 September 2009
Posted by admin in natural hazards, volcano monitoring.Tags: Australia, natural hazards, volcano monitoring
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Australian geologist Prof Bernie Joyce was warning us last week that Australia is ‘overdue’ (his word) for a volcanic eruption. Now he’s decided to alarm the citizens of the Ballarat area of Victoria (in south-east Australia) by telling them they should be ready for a new volcano to emerge, ‘very fast and explosive’, in the local landscape:
Associate Professor Bernie Joyce, who made headlines across Australia last week when he claimed a large volcanic eruption in Victoria was ‘well overdue’, said while volcanoes such as Mt Warrenheip and Mt Buninyong were extinct, a new volcano could arise among the region’s volcano clusters.
‘It could still be thousands of years away, but you should expect it to happen’, he said.
‘Because the ones in the Ballarat area are not as young as (those) in far western Victoria and Mt Gambier, you could expect a new volcano to come up in a cluster’.
Mt Warrenheip and Mt Buninyong are scoria cones: the youngest lavas at the former have been dated to 2.53 (+/-0.15) million years. ‘The well-preserved forms of flows and cones may be indicative of ages of less than 100,000 yr, but the few available K-Ar dates on plains lavas near Ballarat and flows apparently from Mount Rowan and Smeaton Hill are within the range 2.9-2.1 Ma’, says Intraplate Volcanism in Eastern Australia and New Zealand, edited by R. W. Johnson (Cambridge University Press 1989), p. 139.
The prospect of future volcanic activity in Australia is certainly real, but it is also remote – and very difficult to ‘prepare’ for. Prof Joyce argues that ‘given the potential for volcanic activity, emergency authorities must better prepare themselves and the community to respond to it’, but, assuming that he is not suggesting precautionary evacuations or the distribution of breathing masks ‘just in case’, it is not at all clear what the Australian emergency authorities can actually do about the possibility that, at some unknowable and perhaps very distant future date, some farmland may be swallowed up by a new scoria cone, or Ballarat receive a dusting of volcanic ash.
News
New volcano could raise its head here – The Courier, 28 September 2009
1000 posts at The Volcanism Blog 26 September 2009
Posted by admin in admin, blogs, miscellaneous.comments closed
A minor milestone: this is the 1000th post published at The Volcanism Blog since we opened for business on 5 December 2007. Thank you for reading!
