Volcanoes
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Super-volcanoes can form and erupt in hundreds of years, not thousands says new findings

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© SPLEnormous eruptions such as that at Yellowstone result in "calderas", which can become huge lakes
The largest volcanoes on our planet may take as little as a few hundred years to form and erupt.

These "supervolcanoes" were thought to exist for as much as 200,000 years before releasing their vast underground pools of molten rock.

Researchers reporting in Plos One have sampled the rock at the supervolcano site of Long Valley in California.

Their findings suggest that the magma pool beneath it erupted within as little as hundreds of years of forming.

That eruption is estimated to have happened about 760,000 years ago, and would have covered half of North America in its ash.

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500 evacuated from vicinity of Colombia's Nevado del Ruiz volcano

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© UnknownNevado del Ruiz
A light spewing of ash amid renewed rumblings in the Nevado del Ruiz volcano prompted Colombian authorities to evacuate 500 people from beneath its flanks and briefly suspend flights at four airports. The volcano's seismic activity was more intense than episodes in April and early May, when it emitted columns of steam, said the government geological agency Ingeominas. The 17,160ft volcano spouted ash that fell on population centers including the western city of Manizales.

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Growing unrest: preventive alert declared for three Costa Rican volcanoes

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© National Seismological NetworkRincon de la Vieja volcano is showing activity at significant levels experts from the RSN said.
The National Emergency Commission (CNE) on Wednesday declared a preventive "green alert" due to recent seismic activity at three volcanoes: Rincón de la Vieja, in the northwestern province of Guanacaste, Poás, northwest of San José in the province of Alajuela, and Turrialba, in the eastern province of Cartago.

"The CNE's alert is supported by reports from technical and scientific agencies that note the volcanoes are in constant activity," the commission stated.

Turrialba Volcano, 70 kilometers east of the capital, has seen significant volcanic and seismic activity in recent months, prompting the National Seismological Network to upgraded its own color threat level to yellow.

Emissions of gas at Poás Volcano are expected to increase, and Rincón de la Vieja Volcano has also seen significant volcanic activity, the CNE noted.

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Residents evacuated near Costa Rica's Turrialba volcano after gas emission

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© NASATurrialba
Emergency officials in Costa Rica say they have moved some residents away from a volcano outside the capital after it spewed toxic gas and ash, signs of a potentially imminent eruption.

The Turrialba volcano located about 40 miles (65 kilometers) outside San Jose began a series of eruptions in 2007. Several nearby villages were evacuated and a surrounding national park closed in 2010.

Costa Rica's National Emergency Commission said its volcano warning level was at green on Wednesday, the lowest of three warning levels, but that it had alerted residents about the possibility of an evacuation and already moved some villagers away from the populated areas closest to the volcano so they would not be harmed by erupting gases.

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Is an eruption at Costa Rica's Turrialba Volcano imminent?

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© RSNNational Seismological Network volcanologists are keeping an eye on Turruialba Volcano, which they say could erupt soon.
Costa Rica's National Seismological Network has upgraded the color threat level to yellow of Turrialba Volcano, in the province of Cartago east of the capital.

A statement issued by Raúl Mora-Amador, coordinator of Seismology, Volcanology and Geophysical Exploration at the University of Costa Rica, indicates a threat level of yellow means that the National Seismological Network believes an eruption is "probable" in a matter of days, weeks or a few months.

The upgrade in the threat level is due to "important changes in seismic activity of Volcano Turrialba associated with the movement of fluids, gas and magma beneath the surface, different from that observed in past years," Mora-Amador's statement says.

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Guatemala Fuego Volcano Spits Lava and Ash

Fuego Volcano
© Rudy A. Girón/FlickrThe largest eruptions I have ever seen of Volcán de Fuego (Fire Volcano).
Guatemala's Fuego volcano belched burning lava and black ash into the sky early Saturday, leading the government to issue an airplane advisory and close sections of highway.

The volcano, about 25 miles (40 kilometers) southwest of the capital, erupted about 2:45 a.m. (0745 GMT), spewing a column of ash up to 16,400 feet (5,000 meters) above the crater and launching burning red lava nearly 1,300 feet (400 meters) high.

The national emergency commission issued an advisory, warning planes not to fly within a 25-mile (40 kilometer) radius of the volcano. The La Aurora international airport in Guatemala City remained open.

The commission also closed two stretches of highway threatened by lava flows that reached the base of the mountain.

Guatemala's four active volcanoes have a history of causing shut downs. In 2010, an explosion at the Pacaya volcano about 25 miles (40 kilometers) south of Guatemala City coated the city in a thick layer of black ash and rock, forcing hundreds of families to evacuate and closing the international airport.

Cloud Lightning

Volcanic Eruptions Trigger Shocking Finding

Volcanic Lightning
© Brentwood Higman/groundtruthtrekking.orgVolcanic lightning during the 2009 eruption of Alaska's Mount Redoubt enabled researchers to study electrical processes within the ash plume.
Volcanic eruptions can spark squalls of lightning that are as intense as the biggest superstorms over the central United States, according to researchers who have captured the most detailed measurements of electrical discharges during a volcanic blast. The data, they say, could help to illuminate what causes volcanic lightning and point the way towards a system that can quickly detect ash plumes from remote eruptions, which can disrupt air travel.

Observers as far back as Pliny the Elder in 79 AD have noted that eruptions often trigger lightning storms, but researchers have only recently started to set up monitoring stations to capture that electrical activity and study its causes. In early 2009, seismic rumblings beneath Alaska's Mount Redoubt provided an opportunity for a team from the New Mexico Institute of Mining and Technology in Socorro and the University of Alaska in Fairbanks. They raced to the mountain and set up four small monitoring stations with very high frequency (VHF) antennas to record the radiation from any lightning discharges. Two months later, Mount Redoubt erupted and the team was deluged with data.

"We had 16 large volcanic lighting storms, so that was a lot of data to compare between the different eruptions," says Sonja Behnke, a graduate student at the New Mexico institute and first author on a paper about the eruption in the geophysics publication EOS this week1.

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Dramatic eruption seen at Sakurajima volcano in Japan


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Blasts Continue to Menace People Near Popocatepetl Volcano

Fresh blasts from Mexico's Popocatepetl volcano spewed fiery rock and caustic ash over residents around the Mexico City suburb of Puebla, already on edge after weeks of ongoing eruption.

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© Cenapred“It was spectacular. But of course, it makes you worry about everyone living nearby.” — Vulcanologist Raul Arambula.
Ash soared 2.5 miles into the sky during early Saturday's explosion, forcing a local airport to close.

Residents of the nearby village of Santiago Xalitzintla rushed into the town square during the middle of the night as terrifying rumblings and blasts caused buildings to shudder.

Last week residents in eastern parts of Mexico City were provided with face masks to protect them against ash raining over the region from Popocatepetl's blasts.

Prevailing winds have so far spared the capital district from significant ash falls.

Popocatepetl has become increasingly active during 2012.

Bizarro Earth

Sumatra Volcanoes May Pack Deadly Punch

Sumatra
© NASASumatra, Earth's sixth-largest island, spied from space.
The oft-disaster-battered island of Sumatra may have yet another threat to add to the roster of natural phenomena that afflict the Indonesian island: colossal volcanic eruptions.

Although Sumatra residents are likely well-acquainted with the string of volcanoes that line the Indian Ocean island's western coastline, new research has revealed that some of these volcanoes are capable of far more violence than once thought.

"Our study found some of the first evidence that the region has a much more explosive history than perhaps has been appreciated," said Oregon State University's (OSU) Morgan Salisbury, lead author of research recently published in the Journal of Volcanology and Geothermal Research.

"Sumatra has a number of active and potentially explosive volcanoes, and many show evidence of recent activity," Salisbury said in a statement. However, he added, most of the eruptions are small, so little attention has been paid to the potential for a catastrophic eruption.

In 2007, OSU professor Chris Goldfinger led an expedition to Sumatra to dig up evidence of earthquakes that had rocked the region in the past.

During the field work, the OSU team, along with Indonesian colleagues, stumbled upon unmistakable evidence of volcanic ash and began conducting a parallel investigation into the region's volcanic history.