Uitbarsting Mount Redoubt (Alaska)

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Will the Volcano blow?
Anchorage, Alaska (CNN) -- It's 3 degrees and snowing outside the Alaska Volcano Observatory in Anchorage, but inside the operations center, things are heating up.

"This is kind of the nerve center, if you will," says geologist Michelle Coombs, who is at the helm of a bank of video monitors showing readouts from sensors on Mount Redoubt, a volcano about 100 miles southwest of Anchorage.

The sensors measure seismic activity on the volcano's summit. Scientists at the observatory combine that information with data gathered from daily airplane flights to the volcano to measure gases and try to figure out if and when Redoubt is going to blow.



"We're seeing lots of little earthquakes right now," says Coombs. "As that magma rises, it breaks rock as it gets to the surface, and it also it gives off gases, and that leads to the seismic activities were seeing now."

When the magma, or molten rock, makes it to the surface, the volcano will erupt.

A siren goes off, and one of the video monitors goes haywire. Is the mountain erupting?

"That's just a little alarm. There was just a little bit of increased seismic activity," Coombs says reassuringly. "It's a special kind of earthquake particular to volcanoes called a long-period earthquake. It has more to do with fluid and gases than with breaking rock.

Since the monitors first showed increased activity on January 23, the observatory has been staffed 24 hours a day. Scientists here are calling in reinforcements; several geologists from the Lower 48 have been making their way north to help.

Coombs thinks Redoubt will erupt within days or weeks. No one lives near the mountain, which sits on the Cook Inlet and is largely surrounded by glacier ice. That means there is no direct danger from lava flows, but huge clouds of ash could spread throughout Alaska.

When Redoubt last erupted in 1989, it spread ash across Alaska for five months.

"Geologists like to use the past as a key to the future, and previous historical eruptions of Redoubt have produced ash clouds of up to 40,000 feet above see level," says Coombs. She notes that at current weather conditions, "it would take about three hours for that ash to leave the volcano and arrive in Anchorage."

The ash is composed largely of silica, which is similar to tiny fragments of glass. Down on the ground, the ash can be dangerous to breath in and can damage cars as their engines draw the ash into their engines. But it is usually a nuisance.

However, in the sky, the ash clouds can create very dangerous flying conditions for jets.

"For jet aviation, it's a very severe hazard because jet engines run at a very high temperature. And once that silica-rich ash gets ingested into the engine, it can remelt and coat the insides of the engines and freeze up those engines," says Coombs. "That's really the major thing we are trying to avoid here."

The day after the 1989 eruption of Redoubt, a 747 flew into an ash cloud near Anchorage and all four engines stalled. The pilot was able to get two of the engines restarted, and the plane landed safely. Coombs says airspace around the volcano and Anchorage may be closed if Redoubt erupts.

When the alarms aren't blaring, Coombs sends out the official Twitter feeds from the observatory and tries to stay warm. She is eight months' pregnant.

"People have been joking, 'Are you going to name him redoubt?' " she says with a laugh, then shakes her head and gets back to her monitors.

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2009-02-04 00:03:35

Unrest at Redoubt Volcano continues. Seismic activity remains elevated above background and has been fairly stable all day.

AVO staff successfully installed two new seismic stations at Redoubt today. The weather may close in tomorrow and obscure web cam views for a few days.

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2009-02-06 01:29:09

Unrest at Redoubt Volcano continues. Seismic activity remains elevated well above background levels. The volcano has not erupted.

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2009-02-11 14:43:39

Redoubt Volcano has not erupted. Low amplitude volcanic tremor and intermittent small earthquakes continue. Web cams are obscured by snowy conditions in Cook Inlet.

AVO is monitoring the volcano 24 hours a day.

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2009-02-11 12:42:50

Redoubt Volcano has not erupted. Elevated seismicity continues to be dominated by ongoing, low amplitude volcanic tremor and intermittent small earthquakes.

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Op maandag 2 februari 2009 09:24 schreef Frutsel het volgende:
De Redoubt laat nog ff op zich wachten... dus plofte die in Japan maar... de Asama
Uitbarsting Asama

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2009-02-23 02:16:24

Redoubt Volcano has not erupted. Volcanic tremor and intermittent discrete earthquakes continue. Data for the past few hours (since 00:00 AST on 2/23) has consisted almost entirely of low-level tremor.

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Current Status
On the basis of declining seismicity, a possible decrease in heat flux, and no apparent change in gas emission, the likelihood of an eruption of Mount Redoubt within days to weeks has diminished. Accordingly, AVO lowered the alert level to YELLOW/ADVISORY on Tuesday, March 10, 2009, and ceased round the clock staffing of the AVO operations center. The volcano remains on a heightened monitoring schedule, and AVO scientists will continue to evaluate conditions at the volcano regularly. The volcano remains restless and it is still possible, though far from certain, that the current episode of volcanic unrest at Mount Redoubt could result in an eruption.

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Op vrijdag 13 maart 2009 11:30 schreef OA het volgende:
Valt weer tegen dan...

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Redoubt rumbles again
ANCHORAGE, Alaska — Alaska's Mount Redoubt is rumbling again and geologists at the Alaska Volcano Observatory increased the official alert level to orange, the stage just before eruption.

A significant eruption did not appear imminent, geologists said Sunday, but they cautioned that conditions could evolve rapidly.

The 10,200-foot Redoubt Volcano is about 100 miles southwest of Anchorage.

Ash from the volcano could harm engines and is especially dangerous for aircraft. Ash blown to cities also can cause respiratory problems.

Residents of south-central Alaska have kept a close eye on Redoubt since the observatory on Jan. 25 warned that an eruption could occur at any moment. The alert level was downgraded last week after nearly two months.

Just after 1 p.m. Sunday, however, seismic activity picked up again.

"We got a return of this stuff we call volcanic tremors," said geologist Chris Waythomas. "Think of the phenomenon that produces sound in an organ pipe."

Instead of sound waves in a pipe, geologists detect movement of magma within cracks and fractures of the mountain that resonates and produces a distinct signal.

"We think it's associated with the hydrothermal system there. It's being reinvigorated," Waythomas said.

The tremors lasted about four hours and then settled down.

An observatory flight Sunday reported that a steam and ash plume rose as high as 15,000 feet (4,600 meters) above sea level and produced minor ash fall on the upper south flank of the mountain. Later reports indicated the plume had changed into mostly steam.

Ash emission had not been seen before, Waythomas said, and until samples are taken, geologists will not know whether it's new magma or, more likely, old ground-up material from previous episodes.

Other signs that a volcano could erupt are deformities in the landscape and the mix of gases escaping from vents on the side of the mountain.

Alaska volcanos typically explode and shoot ash upward, sometimes to 50,000 feet (15,000 meters), high into the jet stream. An eruption of Redoubt on Dec. 15, 1989, sent ash 150 miles (240 kilometers) away into the path of a KLM jet, stopping its engines. The jet dropped more than two miles (three kilometers) before the crew was able to restart engines and land safely at Anchorage.

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BREAKING NEWS — Alaska's Mt. Redoubt volcano erupted late Monday and early Tuesday in "three large explosions," sending an ash plume an estimated 50,000 feet into the air, the Alaska Volcano Observatory reported.

Geologists at the observatory say the volcano, located 100 miles southwest of Anchorage, erupted three times late Sunday and early Monday.

Geophysicist John Power said, "this is a fairly large eruption, close to the larger cities in Alaska."

He says no cities have yet reported any ash fall from the volcano, but noted that it's still early.

Winds were expected to carry the ash plume north toward the Susitna Valley, possibly missing Anchorage to the east, the National Weather Service told the Anchorage Daily News.

"It looks like (Anchorage) might dodge the bullet," Alaska Volcano Observatory geophysicist Peter Cervelli told the paper.

The volcano observatory raised the aviation color code to Red, its highest level, and the alert level to Warning after the eruption began at 10:38 p.m. local time (2:38 a.m. Monday EDT.)

An official at Anchorage International Airport told the Daily News early Monday there were no immediate plans to close the airport.

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Ashfall warning for anchorage

WWAK71 PAFC 230733
NPWAER

URGENT - WEATHER MESSAGE
NATIONAL WEATHER SERVICE ANCHORAGE AK
1133 PM AKDT SUN MAR 22 2009


AKZ145-231200-
/X.NEW.PAFC.AF.Y.0001.090323T0733Z-090323T1200Z/
SUSITNA VALLEY-
INCLUDING THE CITIES OF...TALKEETNA...WILLOW...CANTWELL
1133 PM AKDT SUN MAR 22 2009

...ASHFALL ADVISORY IN EFFECT UNTIL 4 AM AKDT MONDAY...

THE NATIONAL WEATHER SERVICE IN ANCHORAGE HAS ISSUED AN ASHFALL
ADVISORY...WHICH IS IN EFFECT UNTIL 4 AM AKDT MONDAY.

REDOUBT VOLCANO AT 60.5N 152.7W HAS ERUPTED AT AROUND 1040 PM
AKDT. VOLCANIC ASH IS FALLING AND IS EXPECTED TO REACH THE SURFACE
ACROSS THE SUSITNA VALLEY. PRELIMINARY INDICATIONS ARE THAT
ASHFALL WILL BE VERY LIGHT.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

AN ASHFALL ADVISORY MEANS THAT ASH WILL BE DEPOSITED IN THE
ADVISORY AREA. PEOPLE IN AREAS OF ASHFALL SHOULD SEAL WINDOWS AND
DOORS. PROTECT ELECTRONICS AND COVER AIR INTAKES AND OPEN WATER
SUPPLIES. MINIMIZE DRIVING. LISTEN TO YOUR RADIO STATION FOR
FURTHER INFORMATION.

thx voor de update Mouzzer

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Another large explosion rocks Redoubt