(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued:(20140102/2019Z)
(3) Volcano:Cleveland (CAVW# 1101-24-)
(4) Current Color Code:ORANGE
(5) Previous Color Code:yellow
(6) Source:Alaska Volcano Observatory
(7) Notice Number:2014/A1
(8) Volcano Location:N 52 deg 49 min W 169 deg 56 min
(9) Area:Aleutians Alaska
(10) Summit Elevation:5676 ft (1730 m)
(11) Volcanic Activity Summary:Cleveland Volcano appears to have entered a renewed phase of elevated unrest and AVO is moving the Aviation Color Code and Alert Level from Yellow/Advisory to ORANGE/WATCH. Three brief explosions were detected over the past six days on Saturday Dec. 28, Monday, Dec. 30, and at 04:00 UTC, Jan. 2, 2014 (1900 AKST Jan. 1). Minor ash plumes were observed in satellite data following the events on Dec. 30 and Jan. 2. The plumes were only visible in single satellite images where they appeared as distinct ash plumes, detached from the summit, extending 45 to 60 miles (75 to 100 km) north of the volcano.

The height of the ash plumes generated on Dec. 30 and Jan. 2 is not known. Analysis of satellite, wind, and ash dispersion data indicates that these particular plumes probably did not reach more than 15,000 feet above sea level. Past explosive activity at Cleveland Volcano has produced ash clouds that have risen above 20,000 feet and if explosive activity continues, it remains possible for ash clouds to reach this height or higher.

It is possible for brief, sudden explosions of blocks and ash from the summit vent of Cleveland Volcano to occur with little to no warning. These explosions may produce drifting ash clouds and local fallout of ash over the surrounding ocean, on the flanks of Cleveland Volcano, and on parts of Chuginadak Island. It is possible that more energetic explosions will occur that may produce more significant ash clouds.

If a large ash-producing event occurs, nearby seismic, infrasound, or volcanic lightning networks should alert AVO staff quickly. However, for some events, a delay of several hours or more is possible. Cleveland volcano does not have a local seismic network and is monitored using only distant seismic and infrasound instruments and satellite data.

(12) Volcanic cloud height:Unknown
(13) Other volcanic cloud information:Unknown
(14) Remarks: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 lava flow and hot avalanche that reached the sea. The last minor ash emission following an explosion was on May 5, 2013.
(15) Contacts:Chris Waythomas, Acting Scientist-in-Charge, USGS
chris@usgs.gov (907) 786-7497

Pavel Izbekov, Acting Coordinating Scientist, UAFGI
pavel@gi.alaska.edu (907) 322-4085
(16) Next Notice:A new VONA will be issued if conditions change significantly or alert levels are modified. While a VONA is in effect, regularly scheduled updates are posted at
http://www.avo.alaska.edu