Shishaldin, Unimak Island, Alaska
- April 19, 1999
- Glowing rocks were seen erupting 200
m above the summit of Shishaldin on April 17. Lava was seen on the summit
on April 18, and snowmelt was running down the northwest flank. An explosive
eruption then occurred at Shishaldin on April 19, sending an ash plume
45,000 ft into the air. This event lasted about seven hours. Additional
eruptions could occur with little or no warning, so the concern code
has been raised to Red. Two flights were cancelled and several others
were rerouted when pilots spotted the ash plume. One official stated
that it was one of the most energetic eruptions of Shishaldin this century.
- June 3, 1997
- The National Weather Service in Cold
Bay reported a small steam and ash plume rising 1,000-1,500 feet (300-450
m) above the summit of Shishaldin. The plume has drifted about 5 miles
(8 km) to the north. The Alaska Volcano Observatory noted that Shishaldin
is not seismically monitored but has frequent small eruptions.
- Shishaldin Volcano on Unimak Island in
the eastern Aleutian Islands erupted early Saturday morning, December
- Pilots reported an ash plume as high
as 35,000 feet (10,700 m) above sea level.Analysis of a satellite image
by volcanologists at the Alaska Volcano Observatory showed a possible
small ash plume extending approximately 50 km northwest of Shishaldin.
The observatory also received a report of a possible very light ashfall
at Cold Bay, 56 miles (90 km) northeast of Shishaldin.
- Shishaldin Volcano is located near the
center of Unimak Island in the eastern Aleutian Islands. It is a spectacular
symmetric cone with a summit elevation of 9,373 ft (2,857 m) above sea
level. A small summit crater produces a steady, vigorous cloud of steam
with occasional small amounts of ash. Shishaldin is one of the most
active volcanoes in the Aleutian volcanic arc, erupting at least 27
times since 1775. The most recent eruptive period occurred i n 1986-1987;
activity consisted of minor steam and ash emission that continued for
several months. The nearest village is False Pass, 20 miles (32 km)
east-northeast of the volcano.
- Based on the record of historic activity
at Shishaldin, additional eruptions of ash may continue intermittently
for days or weeks. The Alaska Volcano Observatory will continue to monitor
the situation through pilot reports and analysis of satellite images.
- On Friday, January 12, 1996, the Alaska
Volcano Observatory reported detection of a intermittent "hot spot"
near the summit of Shishaldin. The "hot spot" was first noticed
on AVHRR satellite images of the volcano on January 5, 1996. Volcanologists
at the Alaska Volcano Observatory think the extra heat is caused by
high temperatures in the vicinity of the continuously active fumaroles
in the summit crater.