Tuesday, November 28, 2006
Volcano eruption in Eastern Congo
Mount Nyamulagira began erupting about 10 p.m. (2200 GMT) Monday, said Celestin Kasereka, head of the Goma volcano observatory.
In 2002, the eruption of neighboring Mount Nyirangongo destroyed one-fifth of the residential areas of Goma, the provincial capital of Congo's North Kivu province. About 100 people died when lava flows as deep as 10 feet (3 meters) overtook parts of the city of 500,000.
Nyamulagira erupted later the same year, spewing plumes of lava 300 feet (90 meters) into the air, but without threatening Goma. Kasereka said Goma is not in the path of lava flows from Nyamulagira because its sister volcano protects the city.
"Nyirangongo constitutes a barrier,'' Kasereka said. Nyirangongo and Nyamulagira, about 13 miles (20 kilometers) and 25 miles (40 kilometers) northeast of Goma, are the only two active volcanoes in the region. On the western side of Goma, clashes between forces loyal to a dissident former general and Congo's army have killed at least three in recent days and pulled in U.N. forces and an attack helicopter Monday. The fighting has been centered around the town of Sake, about 30 kilometers (18 miles) west of Goma _ the opposite direction of the volcanoes.
Kasereka said observation of the site had been difficult because of the unrest in the region. Largely lawless eastern Congo has been home to numerous rebellions in recent years as rival warlords claim swaths of land _ some hanging on despite recent elections designed to unify the country under democratic rule.
Nyamulagira erupts every year or two, but rarely affects populated areas. Kasereka did not say if the eruptions were continuing.
First recorded underwater eruption
Geologist Maya Tolstoy of the Lamont-Doherty Earth Observatory in Palisades, N.Y., lead author of a recent Science Express paper on the finding, said that earthquake activity on the sea bottom steadily increased from 2003 to 2005, and predicted that an eruption was imminent.
The research has "exciting implications that we may be able to anticipate future sea floor eruptions," said scientist James Cowen of the University of Hawaii in Honolulu, a co-author of the paper.
Scientists aboard the research vessel (R/V) Knorr confirmed evidence of the volcanic activity in April, 2006, when they tracked the locations of 12 ocean-bottom seismometers (OBSs) designed to monitor earthquake activity on the East Pacific Rise tectonic plate boundary, located south of the Gulf of California.
When only four of the 12 OBSs were recovered, the scientists became suspicious that a lava flow might have covered or damaged them. Although equipment malfunction was a possibility, the seismometers in previous experiments had been retrieved in 98 percent of deployments.
"If you have to lose instruments on the sea bottom," said Tolstoy, "this is the only way to do it--when the information gained from their loss is extensive. The disappearance of these instruments underscores the importance of real-time monitoring on the sea floor. We learned an enormous amount by having these instruments placed where they were: right on top of the eruption."
The seismometers are part of an ongoing, detailed study of the creation of new sea floor at the East Pacific Rise sponsored by the National Science Foundation (NSF) through its RIDGE 2000 program, which is investigating mid-ocean ridges and sea-floor spreading centers. The site has been designated one of three focus areas in the RIDGE 2000 program.
"Through efforts like RIDGE 2000, we're getting a glimpse of what will be possible when we are able to monitor seafloor activity of all kinds--tectonic, volcanic, hydrothermal and biological--in real time," said Rodey Batiza, program director in NSF's Division of Ocean Sciences, which funds RIDGE 2000.
In 2006, scientists measured changes in the chemistry of fluids coming out of vents as compared to a previous eruption documented in 1991, and inferred that changes in the flow of undersea magma were happening.
As sea water heated by subsurface magma jets out from cracks in the ocean crust, it rises, then spreads out in a cloudlike formation 200 to 250 meters above the sea floor. In the spring 2006 eruption, the cloud was detected 4 miles south of where active venting was documented. Rocks were dredged from the sea floor in one of the most active areas of venting. The surface of the basaltic rocks was glassy and iridescent, indicating very recent cooling of hot magma by contact with cold seawater.
Other co-authors include Ed Baker of NOAA's Pacific Marine Environmental Laboratory in Seattle, Wash., and Dan Fornari of the Woods Hole Oceanographic Institution in Mass.
Mount St.Helens activity is not a repetition of the 1980 desastrous eruption
Writing in the journal Nature, scientists led by Richard Iverson of the US Geological Survey said these quakes appear to result from the movement of a huge plug of igneous rock known as dacite being shoved out of the volcano.The good news, they said, is that the volcano appears to be brooding rather than bursting, and the recent quakes seem unlikely to be a harbinger of a massive eruption along the lines of the one that occurred on May 18, 1980.
That one blew off the upper 400m of the mountain, levelled thousands of acres of forest land, killed 57 people and coated the region with gritty ash. The eruption was triggered by a magnitude 5.1 earthquake that shook Mount St Helens."There's really nothing that we've seen over the past two years that would indicate that a major explosive eruption is on the way," Iverson said in an interview.
But Iverson gave himself a little bit of wiggle room."Now, of course, things could always start to change. If we saw, for example, dramatic increases in the amount of gas that was coming out of the volcano or dramatic increases in deformation, then we would revise our forecasts," he said.Mount St Helens is the most active of the volcanoes in the Cascades Mountains, and geologically young compared to the others. It is believed to have the potential at some point in the future for another big eruption.
"I know everybody was conditioned by the May 1980 eruption to think of Mount St Helens as this very explosive volcano. And certainly it had done that prior to 1980 and will do that again in the future. But this ongoing eruption is of a completely different style," Iverson said.Scientists call what it going on now a dome-building eruption and note that it has continued on a steady basis for a bit longer than two years.
The huge plug of rock now being shoved out of Mount St Helens is going at a rate of about three to six metres per day, advancing in fits and starts and triggering tremors, the scientists found.Mount St Helens, standing 2 550m in elevation, is located about 160km south of Seattle, Washington, and 80km north-east of Portland, Oregon.
Mount Etna's eruptions close Sicily airport
The Fontanarossa airport, the main facility in eastern Sicily, would stay closed at least until early Saturday, "when the state of the volcanic phenomenon and possible reopening of the airport will be examined," the airport said on its web site.
"This is all part of Etna's normal activity," said Antonella Scalzo, a geologist with Italy's Civil Defense Department. "The ash is a nuisance, it's not a precursor of a change in activity."
The 10,974-foot-high volcano resumed eruptions in early September and has sent lava streaming as far down as 7,546 feet. Scalzo said that is a safe distance from people's homes, which don't go any higher up the volcano than 2,297 feet.
Civil Protection Department spokesman Roberto Forina said the only damage from the ash had been the airport's closure.
Mount Etna, Europe's biggest and most active volcano, springs to life every few months. In 1669, a huge eruption destroyed Catania, on Sicily's eastern coast. Etna's last major eruption was in 1992.
Friday, November 24, 2006
Underwater volcano eruption witnessed by scientists
The outburst happened 640 kilometres west of Mexico, along its notorious volcanic mountain range called the East Pacific Rise, some 2,500 metres beneath the Pacific Ocean surface.
Scientists realized something bizarre was happening when only four of their seven underwater instruments responded to instructions to resurface.
They used equipment onboard their vessel to check for temperature, salinity and turbidity near the ocean floor and discovered the water was unusually cloudy and warm.
They confirmed the presence of a recently-formed rock, and with a deep-diving camera system, found the formation of new black, glassy lava.
They also discovered why their three instruments couldn't resurface: they were trapped by the lava flow.
Witnessing and recording this particular type of event was a first.
"There was at least one site that was a lush site with tubeworms, crabs and mussels and it was just gone, just buried," Mike Perfit, a University of Florida researcher on the scene said in a press release Thursday.
Unlike volcanoes located above sea-level, underwater volcanoes spew lava gently because of the enormous ocean pressure, forming pillow-like structures along the seafloor.
The team hopes to go back next spring to retrieve additional data that may enable them to predict such eruptions in the future.
Thursday, November 23, 2006
Volcano eruptions in Iceland are responsible for the famine in Africa
A series of 10 eruptions from the Laki Craters changed atmospheric conditions in most of the Northern Hemisphere and led to unusual temperature and precipitation patterns that peaked in the summer of 1783, causing below normal rainfall in most of the Nile drainage basin and record low levels for up to one year following the eruptions.
"Some of the driest weather occurred over the Nile and Niger River watersheds," explained lead author Luke Oman, a researcher from Rutgers University, NJ. "The relative lack of cloud cover and increased temperature likely amplified evaporation, further lessening water available for run-off."
Large amounts of sulfur dioxide are released into the atmosphere when volcanic eruptions takes place. Aerosol particles, which reflect sunlight back into space, form when this gas combines with water vapor. The result is cooler average temperatures on Earth.
Researchers used computer models to simulate how Iceland's Laki eruptions affected temperature and rainfall levels over the Sahel, a stretch h of land from the Atlantic ocean to the "Horn of Africa."
"These findings may help us improve our predictions of climate response following the next strong high-latitude eruption, specifically concerning changes in temperature and precipitation," Oman said. "Many societies are very dependent on seasonal precipitation for their livelihoods, and these predictions may ultimately allow communities time to plan for consequences, including impacts on regional food and water supplies."
Simulations showed that the aerosols formed by the eruptions cooled average temperatures in the Northern Hemisphere by up to 5.4 degrees Fahrenheit. Tree ring data in Alaska and Siberia also showed reduced growth during the same summer, signifying cooler than normal weather.
The unusually cool temperatures reduced the temperature difference between the land masses of Africa and Eurasia and their respective water masses, the Atlantic and Indian oceans. Usually, a sharp contrast in temperature between land and sea creates raging monsoon winds. Monsoons are seasonal shifts in wind direction that signify the beginning of the rainy season.
The lack of monsoons led to a reduction in cloud cover over the Sahel of Africa, southern Arabian Peninsula and India that summer. This caused temperatures to increase by as much as 3.6 degrees Fahrenheit and induced drought in the region. The resulting food shortage reduced the population of the Nile Valley by a sixth.
The study was detailed in the Sept. 30 issue of the American Geophysical Union's Geophysical Research Letters.
Wednesday, November 22, 2006
Yellowstone is being monitored!
Jake Lowenstern, a USGS geologist and head of the Yellowstone Volcano Observatory, said the survey’s proposal is meant as a starting point for launching discussions about how best to monitor seismic activity in the park. “It’s our way of thinking through what sort of techniques would be useful, what we do and why, and then where do we fall short and how we might improve,” Lowenstern said.
The proposal suggests upgrading Yellowstone’s seismic network with more gauges to monitor streams and potentially dangerous gases, GPS stations that help predict ground-splitting explosions and even instruments hundreds of feet below the ground to monitor groundwater, magma and shifting rocks. “In terms of knowing whether an eruption is going to happen, we already have a pretty good system,” Lowenstern said.
But geologists say at least equal attention should be paid to hydrothermal explosions that, aside from earthquakes and landslides, pose the greatest threat. At least 20 large craters in the park were made by explosions over the last 15,000 years that erupted from boiling groundwater just below the surface. About 2,000 earthquakes also shake the park each year. Most of them are so small they are not even felt, but the magnitude 7.5 earthquake at Hebgen Lake in 1959 killed 28 people and caused extensive damage.
“All (of those) geologic events can occur again at Yellowstone and some likely will within the coming decades,” says the USGS plan. Yellowstone’s volcanic system was classified as a “high-threat” system by the federal government in a report last year that noted the park doesn’t have enough gauges and gadgets to keep track of it. Upgrading the system would help detect “subtle, precursory changes that are likely to occur before hazardous events” so people can be given plenty of notice, the USGS said in its proposal.
There are already 26 seismic stations in Yellowstone. Satellites, GPS stations and other Instruments also monitor its movements. One of the shortcomings of the current system is that in a large earthquake, the instruments might be so disrupted they couldn’t faithfully record what’s going on. Some of the technology is also outdated — much of it is analog, not digital — and the park doesn’t have a redundant system that would allow important geologic data to be relayed outside the park in the case of a large-scale event.
Any new instruments, including those buried in the ground, would need approval from the National Park Service. Though there has been talk of putting more devices in the backcountry, Lowenstern said USGS tries to be as unobtrusive as possible. “A lot of what we’ve done is try to put as many instruments as we can in places that are already developed,” he said.
Mt. St.Helens volcano is still active
Mount St. Helens, in Washington state in the U.S. Pacific Northwest, reawakened in the fall of 2004 with new eruptions, and has produced thousands of shallow, regular, repetitive earthquakes since then.
Writing in the journal Nature, scientists led by Richard Iverson of the U.S. Geological Survey said these quakes appear to result from the movement of a huge plug of igneous rock known as dacite being shoved out of the volcano.
The good news, they said, is that the volcano appears to be brooding rather than bursting, and the recent quakes seem unlikely to be a harbinger of a massive eruption along the lines of the one that occurred on May 18, 1980.
That one blew off the upper 1,300 feet of the mountain, leveled thousands of acres of forest land, killed 57 people and coated the region with gritty ash. The eruption was triggered by a magnitude 5.1 earthquake that shook Mount St. Helens.
"There's really nothing that we've seen over the past two years that would indicate that a major explosive eruption is on the way," Iverson said in an interview.
But Iverson gave himself a little bit of wiggle room.
"Now, of course, things could always start to change. If we saw, for example, dramatic increases in the amount of gas that was coming out of the volcano or dramatic increases in deformation, then we would revise our forecasts," he said.
Mount St. Helens is the most active of the volcanoes in the Cascades Mountains, and geologically young compared to the others. It is believed to have the potential at some point in the future for another big eruption.
"I know everybody was conditioned by the May 1980 eruption to think of Mount St. Helens as this very explosive volcano. And certainly it had done that prior to 1980 and will do that again in the future. But this ongoing eruption is of a completely different style," Iverson said.
Scientists call what it going on now a dome-building eruption and note that it has continued on a steady basis for a bit longer than two years.
The huge plug of rock now being shoved out of Mount St. Helens is going at a rate of about 10-20 feet per day, advancing in fits and starts and triggering tremors, the scientists found.
Mount St. Helens, standing 8,363 feet in elevation, is located about 100 miles south of Seattle, Washington, and 50 miles northeast of Portland, Oregon.
Friday, November 17, 2006
Now you can see volcano eruptions as Google Earth and Space agency team up!
Google Earth Director John Hanke said: “We are inspired to see the European Space Agency using Google Earth to show such fascinating information about our planet through these striking images. This is another important step in helping people around the world to understand more about their environment.”
Strait of Gibraltar as seen by ERS-1ESA’s Director of Earth Observation Programmes Dr. Volker Liebig said: “Integrating ESA images into Google Earth provides an excellent opportunity to create public awareness and interest for space technologies, and in particular for those related to Earth observation and the protection of the environment.
“The imagery has been specifically chosen to afford Google Earth users the possibility to tour the planet from a bird’s eye view and to gain a different perspective and appreciation of their planet by witnessing its splendour as well as its vulnerable spots.”
Tuesday, November 14, 2006
Island born from volcano eruption
Government geologist Kelepi Mafi said he plans to visit the chunk of rock next week if his country can afford to send a military ship there.
Satellite images and passing sailors' reports suggest a new piece of land emerged from the ocean near the northern Tongan island group of Vava'u in early August.
Mafi said no officials had yet been to the site, where yacht crews described an active volcanic island 1.6 kilometers (1 mile) in diameter, with four peaks and a central crater.
Earthquake readings indicate that a "pretty sizable" event had occurred in the area, and photos show a new land mass that is "quite large," Mafi said by telephone from Tonga's capital, Nuku'alofa.
"We are still studying the seismogram ... but we want to send a team to the site itself and look at the eruption," he said.
He hopes that if funding is available, a Tongan Defense Service boat will take a party to the island next week.
The crew of the Maiken, a yacht that left Vava'u in early August, reported on their Web log on Aug. 12 that they saw "rafts" of light, porous pumice stone floating in the water — then spotted the active volcano.
They also posted photos of huge pumice rafts that they encountered after passing Tonga's Late island while sailing toward Fiji.
Mafi said one of Nuku'alofa's eastern beaches also had been "flooded" with black pumice shortly after the eruption.
Ed Venzke, an editor with the Smithsonian Institution's Bulletin of the Global Volcanism Network, said first reports of the new island had come from passing boats, and he has since confirmed its existence from satellite images.
The same volcano last erupted in 1984, producing an island that has since eroded away.
"It looks like there was a similar type of eruption. It has built up a new island and produced huge amounts of pumice," Venzke told The Associated Press by phone from Washington.
He said an Oct. 4 satellite image showed the island was 0.098 square acres (0.04 hectares) in area.
"If it's just pumice that has built up the island, the waves will knock it down and erode it very quickly. It won't last long," he said.
It was not yet known whether the eruption was continuing, or if there is any lava flow.
"But if this eruption continues and produces lava flows, the lava flows will cool and form a hardened shell on the island that will be more resistant to being eroded away," Venzke said.
Volcanoes that produce such eruptions are remote, so little is known about them.
"There are many cases in the past where we received reports of pumice rafts, but had no idea of where the rafts came from," Venzke said.
Richard Wunderman, editor of the Washington-based Bulletin of the Global Volcanism Network, said a large pumice raft, presumably from Tonga, has been sweeping across Fiji, and they were trying to learn about its origins.
A previous eruption in the area generated a small island and similar fields of floating pumice, he said.
Thursday, November 09, 2006
Can volcano eruptions destroy the ozone layer?
The researchers found that even relatively small volcanic eruptions can destroy ozone and create localised ‘holes’ in the stratosphere. Previously, scientists had concentrated on the climatic effects of the tiny particles of volcanic sulphate created from the sulphur dioxide gas emitted during an eruption. For the first time, analysing data from a 2000 eruption of the Hekla volcano, Iceland, the researchers discovered that volcanic gases may also lead to the formation of ice and nitric acid particles.
This is a critical finding as these particles ‘switch on’ volcanic chorine gases, accelerating reactions that lead to ozone destruction.Dr Millard said: 'We have shown for the first time that volcanic eruptions which penetrate the stratosphere can lead to the formation of the type of clouds that promote reactions with volcanic chlorine gases - gases that destroy stratospheric ozone and lead to the formation of "mini-ozone holes".
The ozone losses due to the small eruption at Hekla lasted for about two weeks, and eventually returned to normal levels. This is the first time that people have observed the complete removal of local ozone following a volcanic eruption. 'Now we want to find out what might happen to the ozone layer after a much larger eruption', said Dr David Pyle, University of Oxford, project coordinator, 'for example is there significant loss of ozone, and increased ultra-violet radiation, at low latitudes following large explosive eruptions?
We want to understand this, so that we can have a better picture both of what might have happened in the past, and of what may happen in the future.'
Saturday, November 04, 2006
Mount Cleveland in Alaska spits up ashes!
Satellite data confirmed the presence of a drifting ash cloud moving ENE of the volcano. Based on satellite data, AVO estimated the height of the cloud to be 20,000 ft. above sea level, though one pilot report had it in excess of 30,000 ft.
AVO is raising the aviation color code to Orange and the volcanic activity alert level to Watch.
Short-duration eruptions such as this have been typical of Cleveland over the last several years. This is the fourth such known eruption this year, the previous one having occurred on August 24.
Cleveland Volcano is just west of Dutch Harbor, about 940 miles from Anchorage.