Alaska - Cleveland volcano: aviation color code/volcano alert level raised to Orange/Watch

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<CENTER>ALASKA VOLCANO OBSERVATORY WEEKLY UPDATE</CENTER><CENTER>Friday, July 22, 2011 1:09 PM AKDT (Friday, July 22, 2011 21:09 UTC)</CENTER>

CLEVELAND VOLCANO (CAVW #1101-24-)
52?49'20" N 169?56'42" W, Summit Elevation 5676 ft (1730 m)
Current Volcano Alert Level: ADVISORY
Current Aviation Color Code: YELLOW

On Wednesday, July 20,2011 AVO raised the aviation color code/volcano alert level for Cleveland volcano to Yellow/Advisory following the detection of persistent thermal anomalies in satellite data. A thermal anomaly was detected in satellite images this morning. No other activity has been observed at the volcano.

Without a real-time seismic network at Cleveland, AVO is unable to track local earthquake activity related to volcanic unrest. Short-lived explosions with ash clouds that could exceed 20,000 ft above sea level can occur without warning and may go undetected on satellite imagery for hours. Low-level ash emissions at Cleveland occur frequently and do not necessarily mean a larger eruption is imminent. AVO continues to monitor the volcano using satellite imagery.

Cleveland volcano forms the western half of Chuginadak Island, a remote and uninhabited island in the east central Aleutians. It is located about 75 km (45 mi.) west of the community of Nikolski, and 1500 km (940 mi.) southwest of Anchorage. The volcano's most recent significant eruption began in February, 2001 and it produced 3 explosive events that produced ash clouds as high as 12 km (39,000 ft) above sea level. The 2001 eruption also produced a rubbly lava flow and hot avalanche that reached the sea. The most recent minor ash emission was in September 2010.

http://www.avo.alaska.edu/activity/avoreport.php?view=update

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Re: Alaska - Cleveland volcano: aviation color code/volcano alert level raised to Orange/Watch (August 2, 2011)

AVO/USGS Volcanic Activity Notice

Volcano: Cleveland (CAVW #1101-24-)

Current Volcano Alert Level: WATCH
Previous Volcano Alert Level: ADVISORY

Current Aviation Color Code: ORANGE
Previous Aviation Color Code: YELLOW

Issued: Tuesday, August 2, 2011, 3:43 PM AKDT (20110802/2343Z)
Source: Alaska Volcano Observatory
Notice Number: 2011/A3
Location: N 52 deg 49 min W 169 deg 56 min
Elevation: 5676 ft (1730 m)
Area: Aleutians Alaska

Volcanic Activity Summary: Observations of Cleveland Volcano from Friday July 29, 2011 show a small lava dome about 40 meters (131 feet) in diameter in the summit crater. In response, AVO is raising the Aviation Color Code to Orange and the Alert Level to Watch.

The lava dome was extruded sometime after July 7 when the last clear view of the summit area was acquired. The formation of a lava dome is consistent with observed thermal anomalies seen since July 19, 2011 suggesting that the dome extruded since that time.

A weak thermal anomaly persists at the summit and may indicate that the lava dome continues to slowly grow or that dome growth has ceased and the dome is slowly cooling. If dome growth continues, lava flows onto the flanks of the volcano may develop but would not be hazardous to aviation. The presence of the lava dome increases the possibility of an explosive eruption, but does not necessarily indicate that one will occur. Short-lived explosions could produce an ash cloud that exceeds 20,000 ft above sea level. These events can occur without warning and may go undetected in satellite imagery for hours.

Without a real-time seismic network at Cleveland, AVO is unable to track local earthquake activity related to volcanic unrest, provide forecasts of potential eruptions, or confirmation of explosive activity. Low-level ash emissions and elevated surface temperatures such as those observed recently do not necessarily mean a larger eruption is imminent. AVO continues to monitor the volcano using satellite imagery.

Recent Observations:
[Lava flow/dome] 40 meter diameter lava dome in summit crater as of July 29, 2011
[Volcanic cloud height] Unknown
[Other volcanic cloud information] Unknown

http://www.avo.alaska.edu/activity/report_getter.php?need=current&id=16812&type=3

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Re: Alaska - Cleveland volcano: aviation color code/volcano alert level raised to Orange/Watch

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Aerial photograph of Cleveland's August 2011 lava and summit crater.

This lava dome was extruded sometime after July 7 when the last clear view of the summit area did not show this feature. The formation of the lava dome is consistent with thermal anomalies observed in satellite imagery since July 19, 2011. This dome is approximately 60 m in diameter in a 200m-wide crater. Photograph courtesy of Dave Withrow, National Oceanic and Atmospheric Administration.

Picture Date: August 08, 2011
Image Creator: Withrow, Dave;
Image courtesy of the photographer and National Oceanic and Atmospheric Administration.

http://www.avo.alaska.edu/image.php?id=36282

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<CENTER>ALASKA VOLCANO OBSERVATORY CURRENT STATUS REPORT</CENTER><CENTER>Tuesday, August 9, 2011 04:05 PM (Wednesday, August 10, 2011 00:05 UTC)</CENTER>

CLEVELAND VOLCANO (CAVW #1101-24-)
52?49'20" N 169?56'42" W, Summit Elevation 5676 ft (1730 m)
Current Volcano Alert Level: WATCH
Current Aviation Color Code: ORANGE

Thermal anomaly at the summit of Cleveland volcano observed overnight in several satellite images. Effusive eruption of lava dome in summit crater possibly continuing. AVO has received no additional information or observations about unrest at the volcano.

Without a real-time seismic network on the volcano, AVO is unable to track local earthquake activity related to volcanic unrest, provide forecasts of eruptive activity, or confirmation of explosive, ash-producing events. AVO is monitoring the volcano using satellite data as it becomes available.

http://www.avo.alaska.edu/

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Re: Alaska - Cleveland volcano: aviation color code/volcano alert level raised to Orange/Watch

<CENTER></CENTER>
Worldview satellite image collected on August 9, 2011 of the summit crater of Cleveland Volcano. The irregularly shaped dark object in the center of the image is the newly erupted lava dome. It is surrounded by brightly colored mineral deposits produced by volcanic gas emissions. A thin steam cloud partially obscures the view. Satellite data Copyright 2011 by DigitalGlobe.

Picture Date: August 09, 2011 22:45:00 UTC
Image Creator: Schneider, Dave;
Image courtesy of AVO/USGS, copyright 2011 DigitalGlobe.


ALASKA VOLCANO OBSERVATORY CURRENT STATUS REPORTSunday, August 14, 2011 12:27 PM AKDT (Sunday, August 14, 2011 20:27 UTC)

CLEVELAND VOLCANO (CAVW #1101-24-)
52?49'20" N 169?56'42" W, Summit Elevation 5676 ft (1730 m)
Current Volcano Alert Level: WATCH
Current Aviation Color Code: ORANGE

Several thermal anomalies were observed in satellite views of Cleveland Volcano over the past 24 hours.

...

http://www.avo.alaska.edu/

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Re: Alaska - Cleveland volcano: aviation color code/volcano alert level raised to Orange/Watch

Aleutian volcano's behavior a challenge for scientists

By Yereth Rosen
ANCHORAGE, Alaska | Fri Sep 16, 2011 6:53pm EDT

(Reuters) - A volcano in Alaska's Aleutian Islands has been in an unusual low-level eruption for two months, raising the spectre of an explosive eruption with little warning, officials at the Alaska Volcano Observatory said on Friday.

Cleveland Volcano, a 5,676-foot peak located 940 miles southwest of Anchorage, continues to expel lava out its crater, a low-level eruption that began in mid-July, scientists at the Alaska Volcano Observatory said.
Satellite imagery shows a lava dome growing inside the volcano's crater.

Satellite data also shows continued heat generated from the volcano, according to the observatory, a joint federal-state organization.
So far, there have been no signs of ash clouds. But those could come with little warning, scientists said.

"The big thing we're concerned about is an explosive eruption," said Steve McNutt of the University of Alaska Fairbanks, a coordinating scientist for the observatory.

More...

http://www.reuters.com/article/2011/09/16/us-alaska-volcano-idUSTRE78F6KQ20110916

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Re: Alaska - Cleveland volcano: aviation color code/volcano alert level raised to Orange/Watch

Restless Volcanoes

Click for higher resolution image. Cleveland volcano:
Aviation Color Code - ORANGE
Volcano Alert Level - WATCH


<CENTER>ALASKA VOLCANO OBSERVATORY CURRENT STATUS REPORT</CENTER><CENTER>Saturday, September 17, 2011 11:53 AM (Saturday, September 17, 2011 19:53 UTC)</CENTER>

CLEVELAND VOLCANO (CAVW #1101-24-)
52?49'20" N 169?56'42" W, Summit Elevation 5676 ft (1730 m)
Current Volcano Alert Level: WATCH
Current Aviation Color Code: ORANGE

No activity observed in mostly cloudy satellite images from the past day. No ash emissions have been observed during this current eruptive episode that began in mid-July 2011. No other new reports have been received regarding the volcano.

The current episode of dome growth resumed around September 3. A growing lava dome in the crater increases the possibility of an explosive eruption, but does not necessarily indicate that one will occur. Short-lived explosions could produce ash clouds that exceed 20,000 ft above sea level. These events can occur without warning and may go undetected in satellite imagery for hours. If lava dome growth continues, it could overflow the crater rim to produce a lava flow and/or collapse to produce pyroclastic flows. Collapse of a lava flow or dome would likely result in the generation of a volcanic ash cloud.

Without a real-time seismic network on the volcano, AVO is unable to track local earthquake activity related to volcanic unrest, provide forecasts of eruptive activity, or confirmation of explosive, ash-producing events. AVO will continue to monitor the volcano using multiple sources of satellite data.

..

http://www.avo.alaska.edu/

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Re: Alaska - Cleveland volcano: aviation color code/volcano alert level raised to Orange/Watch

<CENTER>ALASKA VOLCANO OBSERVATORY CURRENT STATUS REPORT</CENTER><CENTER>Tuesday, September 20, 2011 12:56 PM (Tuesday, September 20, 2011 20:56 UTC)</CENTER>

CLEVELAND VOLCANO (CAVW #1101-24-)
52?49'20" N 169?56'42" W, Summit Elevation 5676 ft (1730 m)
Current Volcano Alert Level: WATCH
Current Aviation Color Code: ORANGE

Recent observations of Cleveland volcano show that the current eruption, characterized by effusion of lava within the summit crater continues. The size of the lava dome is now about 165 m (540 ft) in diameter compared to 150 m (490 ft) in diameter on September 9,2011. The growing lava dome remains entirely contained within the summit crater but is now approximately 20 meters below the eastern rim.

A growing lava dome in the crater increases the possibility of an explosive eruption, but does not necessarily indicate that one will occur. It is possible that explosions from the summit crater vent could produce ash clouds that may exceed 20,000 ft above sea level. These events can occur without warning and may go undetected in satellite imagery for hours. If lava dome growth continues, lava may overflow the crater rim to produce a lava flow and/or collapse to produce pyroclastic flows. Sudden collapse of the effusing lava could result in the generation of a volcanic ash cloud.

...

http://www.avo.alaska.edu/

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Re: Alaska - Cleveland volcano: aviation color code/volcano alert level raised to Orange/Watch

<CENTER>ALASKA VOLCANO OBSERVATORY WEEKLY UPDATE</CENTER><CENTER>Friday, October 7, 2011 11:02 AM (Friday, October 7, 2011 19:02 UTC)</CENTER>

CLEVELAND VOLCANO (CAVW #1101-24-)
52&#176;49'20" N 169&#176;56'42" W, Summit Elevation 5676 ft (1730 m)
Current Volcano Alert Level: WATCH
Current Aviation Color Code: ORANGE

The eruption of a lava dome in the summit crater of Cleveland Volcano continues. Satellite observations over the past week show that the edge of the dome is now at the level of the crater rim on the southwest and east-northeast sides, and may soon overflow the crater rim on these flanks. At present, most of the lava dome volume is contained within the summit crater, and thus not prone to gravitational collapse. No ash emissions have been detected during the current eruption which began in July, 2011, and AVO has received no other reports of activity at this volcano.

If the lava dome continues to grow in the summit crater, the possibility of an explosive event increases. With continued lava dome growth, lava may eventually overflow the crater rim to produce a lava flow and/or collapse to produce pyroclastic flows. Sudden collapse of the effusing lava could result in the generation of a volcanic ash cloud. However, lava may continue to erupt without an explosive event. It is possible that explosions from the summit crater vent could produce ash clouds that may exceed 20,000 ft above sea level. These events can occur without warning and may go undetected in satellite imagery for hours. However, lightning associated with significant ash-producing events may be detected within minutes using an automated alarm system.

...

http://www.avo.alaska.edu/

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Re: Alaska - Cleveland volcano: aviation color code/volcano alert level raised to Orange/Watch

<CENTER></CENTER>
Worldview-2 visible wavelength satellite image of the summit of Cleveland Volcano collected on October 1, 2011. The summit is covered in snow and observed through a break in the clouds. The growing lava dome is observed as the dark feature in the center of the image with a small steam plume coming from the middle of the dome. North is to the top in this image and snow-free ground south of the dome is due to elevated surface temperatures.

<TABLE cellSpacing=0 cellPadding=2><TBODY><TR><TD>Date: </TD><TD>October 01, 2011</TD></TR><TR><TD>Volcano(es):</TD><TD>Cleveland</TD></TR><TR><TD>Photographer/Creator: </TD><TD>Schneider, Dave; </TD></TR></TBODY></TABLE>

Citation Information:
Image courtesy of AVO/USGS. Image copyright Digital Globe, 2011.
Please cite the photographer and the Alaska Volcano Observatory / U.S. Geological Survey when using this image.

http://avo.alaska.edu/images/image.php?id=41372

[AlaskaDenise]

Re: Alaska - Cleveland volcano: aviation color code/volcano alert level raised to Orange/Watch

Local news tonight is reporting that the lava appears to be almost ready to spill over the top of the crater. They say that might increase the chance of a more serious eruption. I'm not sure how they came to the conclusion.

.