Uitbarsting Mount Redoubt (Alaska)

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Rumbling Alaska Volcano Threatens Anchorage
ANCHORAGE, Alaska — Mount Redoubt continues to rumble and simmer, prompting geologists to say this Alaska volcano could erupt "perhaps within hours to days."

Scientists from the Alaska Volcano Observatory have been monitoring activity round-the-clock since the weekend.

If Mount Redoubt does erupt, it would be the first time this occurred in nearly 20 years. And if won't likely be pretty.


_{Eruption picture of 1990}

History shows that volcanoes in Alaska, including Redoubt, typically erupt explosively, shooting ash almost eight miles high.

This differs from volcanoes in Hawaii, which usually have slow rolling lava ooze out.

The difference is gas trying to escape gets blocked, possibly by a lava dome or a viscous magma that increases the power from beneath, said observatory geologist Jennifer Adleman.

"Its pressure keeps building and building...," she said.

Depending on the winds, the ash plume could be pushed straight at Anchorage, the state's largest city. This has prompted state and city officials to post bulletins on how to deal with the ash.



Tips include:

— Stay inside as much as possible.

— Wear a mask or wet bandanna if going outside.

— Those who wear contacts should consider wearing goggles.

According to the U.S. Geological Survey, volcanic ash features small, jagged pieces of rock and glass.

The last time this 10,197-foot peak blew was during a five-month stretch starting in December, 1989. It disrupted international air traffic and placed a layer of volcanic dust throughout the Anchorage area.

Concerns over an eruption have state and city officials issuing warnings so area residents can deal with an ash storm.

The mountain is about 100 miles southwest of Anchorage.

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Op vrijdag 30 januari 2009 10:11 schreef LoggedIn het volgende:
zijn er geen live cams?

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Mount Redoubt is getting edgy
Mount Redoubt, the Alaskan volcano expected to erupt at any time, is getting a bit more edgy.

The Alaska Volcano Observatory said in a statement Friday "volcanic tremor" has increased in "amplitude."


_{Dark areas show a mudflow from the peak of Mount Redoubt earlier this week.}

The activity on the 10,197-foot peak is "more energetic than that of the previous several days. However, it is still less vigorous than that observed last weekend," the observatory said.

Peter Cervelli, a research geophysicist with the observatory, told CNN that "every indication is that we're heading toward an eruption."

Cervelli said scientists don't know exactly when it will happen, but if it does happen, it could be days or weeks -- or even hours.

"I would not be surprised to see it erupt at anytime," Cervelli said. "We're going to know it when we see it."
Scientists raised the alert status Sunday to a "watch" level, the second-highest, based on seismic activity detected January 23.

The peak is about 100 miles southwest of Anchorage, the state's most populous city.

Mount Redoubt last erupted nearly 20 years ago, in December 1989, and that eruption lasted until April 1990. Geologists think there could be an eruption "similar to or smaller than the one that occurred in 1989-90.

That eruption spread ash in Kenai and Anchorage, where it disrupted air traffic operations. Cervelli said the ash plumes caused engine failure on a jet.

The 1989-90 eruption also spurred volcanic mudflows, or lahars, that flowed east down the Drift River. The ash fall was seen as far away as Fairbanks and the Yukon Territory border

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2009-02-02 03:14:48

A high intensity burst of volcanic tremor occurred from about 2:44 through 2:50 AST this morning at Redoubt. The tremor episode appears to have ended for now. There was no eruption associated with this tremor.

AVO continues to observe potential activity with seismic, satellite and radar data. The volcano has not erupted.

Clear weather views from the web camera show nothing but darkness so far this morning.

The Aviation Color Code remains at ORANGE and the Volcano Alert Level remains at WATCH.

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2009-02-02 21:55:59

Redoubt Volcano remains restless. Seismic activity remains elevated and is well above background levels. The volcano has not erupted.

A gas/observation overflight today reported continued changes in the summit glaciers indicative of heating of the summit area. The flight and hut webcam photos showed a small vapor plume at the summit. The web camera is now dark for the long winter night.

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Op dinsdag 3 februari 2009 11:30 schreef Drugshond het volgende:
tvp.... qua timing gok ik vaak goed.

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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

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Op maandag 23 maart 2009 16:04 schreef Ared het volgende:

[..]

Gewoon in Amsterdam, maar als dat spul in de stratosfeer terecht komt zorgt de jetstream er wel voor dat de rest van het halfrond er ook van kan profiteren.

zie bijvoorbeeld dit artikel van na de uitbarsting van de Kasatochi vorig jaar, ook in Alaska:
http://www.livescience.co(...)volcano-sunsets.html

die rookpluim kwam "maar" tot 10 km.

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6th Eruption of Redoubt
Alaska's Mount Redoubt volcano erupted six times, sending an ash plume more than 9 miles into the air in the volcano's first emissions in nearly 20 years.

Residents in the state's largest city were spared from falling ash, though fine gray dust fell Monday morning on small communities north of Anchorage.

"It's coming down," Rita Jackson, 56, said Monday morning at a 24-hour grocery store in Willow, about 50 miles north of Anchorage. She slid her fingers across the hood of her car, through a dusting of ash.



Ash from Alaska's volcanos is like a rock fragment with jagged edges and has been used as an industrial abrasive. It can injure skin, eyes and breathing passages. The young, the elderly and people with respiratory problems are especially susceptible to ash-related health problems. Ash can also cause damage engines in planes, cars and other vehicles.

Alaska Airlines on Monday canceled 19 flights because of the ash. In-state carrier Era Aviation canceled four, and Elmendorf Air Force Base in Anchorage kept 60 planes, including fighter jets, cargo aircraft and a 747 commercial plane, in shelters.

Five of 20 Alaska state senators were scheduled on the morning flight from Anchorage to Juneau, which was canceled. As a result, consideration of legislation, including a resolution accepting federal stimulus funds, was delayed.

The first eruption, in a sparsely populated area across Cook Inlet from the Kenai Peninsula, occurred at 10:38 p.m. Sunday. The sixth happened happened at 7:41 p.m. Monday, according to the Alaska Volcano Observatory.

The wind took the ash cloud away from Anchorage, toward Willow and Talkeetna, near Mount McKinley, North America's largest mountain.

There were reports of a quarter-inch of ash in Trapper Creek and up to a half-inch at a lakeside lodge near Skwentna.

Dave Stricklan, a hydrometeorogical technician with the National Weather Service, expected very fine ash.

"Just kind of a light dusting," he said. He said the significant amount of ash probably dropped immediately, right down the side of the volcano.

"The heavier stuff drops out very quickly, and then the other stuff filters out. There's going to be a very fine amount of it that's going to be suspended in the atmosphere for quite some time," he said. "The finer ash is going to travel farther, and any ash can affect aviation safety."

Jackson said she was taking a sip of coffee when she tasted something funny on her lips — ash. She was experiencing other affects, too.

"My eyes are itching really bad," she said as she hurried to get out of the store and to her car.

Jackson, who unexpectedly got the day off, left the grocery store to secure a motorcycle, snowmachine and vehicles under protective blue tarps at home.

The 10,200-foot Redoubt Volcano, roughly 100 miles southwest of Anchorage, last erupted during a four-month period from 1989-90.

In its last eruption, Redoubt sent ash 150 miles away into the path of a KLM jet and its four engines flamed out. The jet dropped more than 2 miles before the crew was able to restart all engines and land safely. The plane required $80 million in repairs.

The volcano became restless earlier this year. The observatory had warned in late January that an eruption could occur at any time.

Increased earthquake activity over the past 48 hours prompted scientists to raise the alert level for Mount Redoubt on Sunday.

On Sunday morning, 40 to 50 earthquakes were being recorded every hour.

A steam plume rising about 1,000 feet above the mountain peak was observed Saturday.

Three seismometers on the mountain were damaged in the eruption but seven others remained in place, said observatory geophysicist John Power.

The observatory planned a helicopter flight to the mountain Monday afternoon to sample ash, repair equipment and monitor flooding along the Drift River, which flows from a glacier of the same name.

Power said the history of past eruptions of Redoubt indicate the volcano could erupt again in the next few days or weeks.

"It's something we need to stay prepared for," he said.

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The volcano this evening--after a daylong period of relative calm in the wake of a series of explosions beginning late Sunday night--blew its top for a sixth time, sending a plume of ash and steam 60,000 feet skyward.

There's little more information at this point from the Alaska Volcano Observatory. (To read the L.A. Times story on the effects of the initial explosions, click here.)

The accompanying graphic shows the north-northeast direction of ash fall after the initial explosions. That was a relief to residents throughout the state's more populated south-central quadrant.

But if history is a judge, Alaskans are in for a lengthy period of sporadic explosions, and ash fall will be at the mercy of prevailing winds.

The five-month series of 1989-1990 eruptions from Mt. Redoubt had a severe impact on aviation and the oil industry, as well as on residents and businesses on the Kenai Peninsula, 50 miles to the east.

Because of ash fall, schools on the peninsula were closed for long periods and many residents experienced respiratory problems.

After Monday night's explosion, the National Weather Service issued a new ash-flow advisory, suggesting that residents in the Susitna Valley seal windows and doors and protect water supplies.

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Redoubt activity intensifies

Mount Redoubt volcano in southern Alaska erupted four times on Friday, shooting ash as high as 51,000 feet, scientists said.



The latest eruption took place at 8:30 p.m. (12:30 a.m. Saturday ET), according to the National Weather Service. That eruption followed three other ones earlier Friday.

The eruptions are the latest in a series that began Sunday.

The Alaska Volcano Observatory said the alert level remains at its highest possible designation -- red -- indicating that an eruption is under way or imminent and that the eruption will produce a "significant emission of volcanic ash into the atmosphere."


The weather service said the ash is drifting north and northeast. However, only "very light" amounts are expected to fall Friday in the Anchorage area, about 100 miles east-northeast of the volcano.

Alaska Airlines limited flights to and from Anchorage on Friday, according to the airline's Web site. It canceled all its Thursday flights to and from Anchorage after an eruption earlier in the day sent an ash cloud 65,000 feet high

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2009-04-04 06:35:41

Another significant explosive event occurred at Redoubt Volcano at approximately 5:58 am AKDT (13:58 UTC). At this time, the cloud height is estimated to be 50,000 feet based on National Weather Service radar. The cloud is drifting to the southeast of the volcano. AVO seismometers indicate a lahar has developed in the Drift River Valley.

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2009-04-04 04:59:05

The eruption of Redoubt Volcano continues, but the intensity of ash-production has decreased. The current alert level at Redoubt is WATCH and aviation color code is ORANGE.

Volcanic earthquakes continue as mostly small, shallow events with occasional larger earthquakes.

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Mount Redoubt experienced another explosive eruption on April 4, 2009, according to the Alaska Volcano Observatory. The eruption sent a cloud of volcanic ash and vapor to a height of roughly 15,240 meters (50,000 feet). The cloud drifted toward the volcano’s southeast.
The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite took this picture on April 4, 2009. Mount Redoubt sits on the western side of Alaska’s Cook Inlet, and the volcanic plume blows toward the southeast, across the water. On the eastern side of Cook Inlet, the plume appears to change direction, moving toward the northeast before resuming its general southeastern course. This zigzag trajectory might be explained by different wind directions at different altitudes.
On both the western and eastern sides of Cook Inlet, some of the snowy surface has been colored muddy brown, likely resulting from a coating of volcanic ash.

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In early May 2009, the Alaska Volcano Observatory (AVO) warned that Mount Redoubt could erupt explosively at any time with little or no warning. The AVO cited the volcano’s seismic activity, gaseous output, and lava-dome growth as reasons for concern. The AVO warned that a collapse of the lava dome could send significant amounts of ash and meltwater down nearby Drift Glacier.

The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA’s Terra satellite acquired this image of Mount Redoubt and its surroundings on May 5, 2009, when the volcano exhibited little visible activity besides a plume of vapor. In this false-color image made from a combination of visible and infrared light, the bright white steam plume hovers over the volcano’s summit. Immediately southwest of this plume, clouds appear fairly thin and dull. North of the volcano, pristine snow rests on the land surface, but southeast of the volcano, ashfall from earlier eruptions has stained the icy surface. (In the large image, the vegetation in the coastal areas and in river valeys is red.)

Redoubt is a stratolvolcano—a steep-sloped, conical volcano composed of layers of hardened lava, solidified ash, and rocks ejected by previous eruptions. Starting on March 22, 2009, after weeks of unrest, the volcano suddenly erupted five times in one night. Redoubt remained intermittently active afterward.