Random rumblings: hydrothermal vents re-colonized from afar, Yellowstone swarm, Krakatoa, Mauna Kea testbed, and MSH spiders to Chaitén 2 March 2010Posted by admin in Chaitén, Chile, current research, Hawaii, Indonesia, Krakatau, United States.
Tags: Anak Krakatau, astrobiology, Chaitén, Chile, Hawaii, hydrothermal vents, Mauna Kea, Yellowstone
Hydrothermal vents sometimes colonized from afar (Science News) – ‘Field studies at a hydrothermal vent system where all life was snuffed out by a massive undersea volcanic eruption reveal that these habitats can be repopulated in a matter of months by larvae from distant vents. … Water samples taken near the vents in May 2006 contained the larvae of Ctenopelta porifera, a rock-clinging gastropod called a limpet. By July, these fast-growing creatures had colonized the rocks around the eruption-sterilized vents; by October, they were mature and reproducing. … the nearest hydrothermal system known to host that species is located more than 300 kilometers away.’
Recent Yellowstone earthquake swarm was the second-largest ever (Denver Post) – ‘The Yellowstone earthquake swarm that began on Jan. 17 and ended on Feb. 11 was the second-largest earthquake swarm ever at Yellowstone National Park, according to scientists at the University of Utah. … Not only was the swarm the second-largest ever recorded at Yellowstone but it was longer in time and included more earthquakes than last year’s swarm beneath Yellowstone Lake, which occurred in December 2008 and January 2009, according to the scientists.’
Krakatoa’s child smokes with magic fire in belly (The Age) – ‘As the boat approached Anak Krakatau, the atmosphere was eerie. The smoke of the seasonal forest fires drifting from Sumatra made visibility poor and, before we even sighted the volcano, we heard it: a deep, otherworldly rumble. Then, out of the haze, materialised the cone of Anak Krakatau. Within minutes, thick grey ash billowed out of its caldera into the sky.’
Into the mouth of a volcano (Astrobiology Magazine) – ‘Dr. Inge Ten Kate, a University of Maryland Baltimore County research assistant, led an expedition into a cinder cone atop Mauna Kea, Hawaii, to test the prototype for an instrument that will be a miniature laboratory to discover the composition of rocks and atmospheres on moons, asteroids, and planets across the solar system. … Why a volcano? “The terrain and composition are similar to what we expect to find on the Moon, asteroids, and Mars,” says Ten Kate. “Also, there will be outgassing from the volcano, so we can test our ability to measure trace gases in atmospheres. Finally, the differences among various areas on the volcano’s cinder cone will be subtle, so it’s a good test of our sensitivity and our ability to distinguish different regions.”‘
Mount St. Helens ‘spiders’ will get tryout on Chilean volcano (The Oregonian) – Geological ‘spiders’ packed with instruments to monitor the heaves, sighs and belches of Mount St. Helens, are expected to migrate south this month. Two of the contraptions are headed to Chaiten, a volcano in Chile that began erupting in 2008 after about 9,000 years of dormancy. … The machines helped give the USGS sufficient information to declare in January 2008 that Mount St. Helens recent eruptive phase was over. That kind of certainty is needed at Chaiten, said John Ewert, a volcanologist in the Volcano Disaster Assistance Program. “It’s always hard enough to know when they’ll start erupting,” said Ewert, part of the team that visited the Chilean volcano in January. “It’s even harder to tell when they’ll stop.”‘
Seamounts galore in Oceanography special issue 24 February 2010Posted by admin in current research, submarine volcanism.
Tags: oceanography, seamounts, undersea volcanism, volcanological research
The latest issue (vol. 23, no. 1, March 2010) of the official magazine of The Oceanography Society, Oceanography, is devoted to the study of undersea mountains or seamounts. This special issue is entitled, not surprisingly, ‘Mountains in the Sea’ and features fascinating content by some very distinguished contributors, and, best news of all, the online version is free!
Volcanoes to blame for Cretaceous ocean anoxic event 11 February 2010Posted by admin in climate, current research.
Tags: artificial volcanoes, climate change, Cretaceous anoxic event, volcano research
Research published in a letter in Nature Geoscience: around 94.5 million years ago volcanism released large volumes of sulphur into the atmosphere which triggered huge phytoplankton blooms, which in turn deprived the oceans of oxygen and triggered extensive marine extinctions. The abstract tells it like this:
During the Cretaceous period (~145–65 million years ago), there were several periods of global ocean anoxia, each lasting less than one million years. These events, known as ocean anoxic events, were marked by significant increases in organic carbon burial, and are generally attributed to increased primary productivity in surface waters. The details underpinning the initiation, maintenance and termination of these events, however, remain equivocal. Here we present sulphur isotope data spanning the Ocean Anoxic Event 2 (about 94.5 million years ago) from sedimentary rocks in Colorado that were formed in the Western Interior Seaway; this seaway ran north–south, splitting North America during the Cretaceous. Sulphate levels increased rapidly from relatively low background levels at the onset of the event, most likely from the release of sulphur by massive volcanism, and fell during the anoxic event. We infer that the input of sulphate facilitated increased carbon remineralization, which enhanced nutrient recycling and increased global primary productivity, eventually resulting in widespread ocean anoxia. Our scenario indicates that Ocean Anoxic Event 2 may have persisted until sulphate levels were stabilized by the formation and burial of the sulphur mineral pyrite, which returned primary productivity to background levels. We suggest that fluctuations in sulphate levels may have regulated the marine carbon cycle during past periods of low oceanic sulphate concentration.
And that is why geoengineering the climate with artificial volcanoes is a really bad idea: ‘Like the mid-Cretaceous ocean, most modern lakes are poor in sulphate, so it’s possible that geoengineering the climate could trigger blooms and ultimately anoxia in some lakes’ says researcher Matthew Hurtgen of Northwestern University. ‘We hack the climate at our peril’, warns New Scientist. ‘Volcanoes spewed so much sulphate into the atmosphere 94 million years ago that the oceans were starved of oxygen and 27 per cent of marine genera went extinct. Geoengineering our climate could inflict a similar fate on some lakes’. Such is the climate change dilemma: in trying to avoid (for example) climate-induced tectonic-volcanic geo-apocalyptic mega-mayhem we may cause geoengineering-induced volcanic-toxic extinction-anoxic mega-mayhem instead. Agh.
- Derek D. Adams, Matthew T. Hurtgen & Bradley B. Sageman, ‘Volcanic triggering of a biogeochemical cascade during Oceanic Anoxic Event 2’, Nature Geoscience, 31 January 2010 [doi:10.1038/ngeo743]. Abstract.
Deepest undersea eruption caught on video 18 December 2009Posted by admin in current research, Pacific.
Tags: Pacific, submarine volcanism, volcano videos, West Mata
An explosion at the West Mata Volcano throws ash and rock, with molten lava glowing below (image courtesy NSF/NOAA).
In May this year scientists studying the West Mata submarine volcano in the south-west Pacific as part of the NOAA Vents Program captured the deepest undersea eruption yet filmed on video (as your favourite volcano bloggers reported at the time). The findings and images have just been presented at the AGU Fall Meeting in San Francisco: the NOAA has two videos and a wealth of still imagery. West Mata is at the northern end of the Tonga Arc, and rises to 1174 metres below sea level. The water around the vents is highly acidic: microbial life is present, but shrimps are the only form of animal life to thrive around the vents.
Scientists discover and image explosive deep-ocean volcano – NOAA, 17 December 2009
Marine scientists discover deepest undersea erupting volcano – EurekAlert, 17 December 2009
Deepest volcano caught on Pacific Ocean video – BBC News, 18 December 2009
Underwater volcano erupts – The Times, 18 December 2009
Robot records deepest erupting undersea volcano – Associated Press, 18 December 2009
Oceanographers image the discovery of the deepest explosive eruption on the sea floor – PhysOrg.com, 17 December 2009
Tags: current research, India, Indonesia, Toba, volcanoes and climate
The Toba eruption of ~73000 years ago is perennially fascinating: the world’s largest known Quaternary eruption, this event registered VEI=8 and had a global climatic impact that may have caused the near-extinction of humanity by creating a ‘population bottleneck’ (or perhaps not). The scientist behind the population bottleneck theory, University of Illinois anthropology professor Stanley Ambrose, is a lead author for a new study in the journal Palaeogeography, Palaeoclimatology, Palaeoecology (click here for the abstract) which explores further the impact of the Toba eruption and concludes that its effects were indeed wide-ranging and (crucially for the claim that contemporary human populations were dramatically affected) long-lasting.
The study looked at pollen from a marine core taken in the Bay of Bengal which includes ash from the Toba eruption and at carbon isotope ratios in fossil soil carbonates from directly above and below the Toba ash in three locations in central India. Both analyses indicated a change in the vegetation cover in central India after the Toba eruption, from forests to more open vegetation conditions with a predominance of grasslands. The change in vegetation suggests that significantly drier conditions were produced by the Toba eruption, and that those conditions lasted for at least a thousand years.
Communicating health hazards of volcanic ash fall (Kristi Wallace, USGS) – a method for significantly improving public hazard communication in relation to volcanic ash fall and air quality hazards.
Virtual volcano tours and geologic concepts (Dina Venezky, USGS) – the use of Google Map technology to provide real-time information about volcanoes around the world.
The Perfect debris flow (Richard Iverson, USGS) – large-scale experiments examining debris-flow dynamics.
Evaluating debris flow hazards by helicopter (Carol Finn, USGS) – dangling experiments over volcanoes from helicopters to evaluate hydrothermal alteration of rocks, which can contribute to destructive debris-flow hazards on volcanic flanks.
Tags: Chaitén, Chile, natural hazards, rhyolitic volcanoes, volcanic eruptions, volcano research
New research just published in Nature indicates that the magma feeding the eruption of Chaitén that began in May 2008 rose from the magma chamber to the surface much faster than anyone thought, and much faster than sticky, viscous rhyolite magma has any right to move. This makes the Chaitén eruption even more interesting than it was already, and suggests that rhyolitic volcanoes may spring nasty surprises on us in the future by building up to eruption very quickly.
Blognote: Dr Erik Klemetti has all you need to know about Chaitén’s racy rhyolite over at Eruptions, and offers the opportunity to put your questions to one of the authors of the Nature study, Dr Jonathan Castro.
For all our Chaitén coverage: Chaitén « The Volcanism Blog.
Global Volcanism Program: Chaitén – summary information for Chaitén (1508-41)
SERNAGEOMIN – Servicio Nacional de Geología y Minería (Spanish)
Erupción del Volcán Chaitén – extensive coverage of the Chaitén eruption
Tephra not good for the teeth 29 September 2009Posted by admin in calderas, current research, Germany, Laacher See, natural hazards.
Tags: Eifel volcanic zone, Germany, Laacher See, volcano research, volcanoes and human society
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.
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.
Permian caldera discovered in Italian Alps 22 September 2009Posted by admin in calderas, current research, Italy.
Tags: calderas, supervolcanoes, volcano research
The remains of a caldera that erupted during the Permian (290-248 million years b.p.) have been identified in the Sesia Valley in the Italian Alps. Local uplift has exposed the magmatic plumbing to the depth of 25km, five times deeper than scientists have been able to study previously:
A fossil supervolcano has been discovered in the Italian Alps’ Sesia Valley by a team led by James E. Quick, a geology professor at Southern Methodist University. The discovery will advance scientific understanding of active supervolcanoes, like Yellowstone, which is the second-largest supervolcano in the world and which last erupted 630,000 years ago.
A rare uplift of the Earth’s crust in the Sesia Valley reveals for the first time the actual ‘plumbing’ of a supervolcano from the surface to the source of the magma deep within the Earth, according to a new research article reporting the discovery. The uplift reveals to an unprecedented depth of 25 kilometers the tracks and trails of the magma as it moved through the Earth’s crust.
The discovery was described by Prof Quick and his colleagues in Geology, July 2009 (click here for the abstract), and SMU have a press release, ‘Research Spotlight: the “Rosetta Stone” of supervolcanoes’.