YEARLY SUMMARIES OF VOLCANIC ACTIVITY IN ALASKA

This is a brief summary of notable eruptions in Alaska since the creation of AVO. Sources of information are AVO Updates, Information Releases, Bimonthly reports and files, and the monthly Bulletins of the Global Volcanism Network of the Smithsonian Institution. Address comments and discussion to tneal@tardaddy.wr.usgs.gov.

1988

OKMOK Ash emission from intracaldera cone on 14 and 26 February. Plume reaches 1400 m altitude.

PAVLOF Ash emission events to 600 m above the summit on 28 February and 2 March; possibly continue into August.

AKUTAN Minor ash eruptions from intracaldera cone intermittently in late March through April, late May through July. Plumes rise < 4.1 km above the volcano.

1989

AKUTAN Minor ash emissions from intracaldera cone resume in late February and continue intermittently through late March. Light ashfall in Akutan village.

REDOUBT Major explosive eruption on 14 December follows increase in seismicity; explosions on 15 December accompanied by tephra-fall, pyroclastic flows and lahars in Drift River valley. Continuous eruption of tephra 16-18 December; Tephra plumes to >12 km. Air traffic disrupted including near-fatal jet encounter with ash plume over Talkeetna Mountains on 15 December. Dome growth begins about 22 December.

1990

REDOUBT Explosive eruptions accompanied by dome collapse, pyroclastic flows, tephra falls, lahars on 2, 8, 11, 16 January; 15, 21, 24, 18 February; 4, 9, 14, 23, 29 March; 6, 15, 21, 26 April. Tephra plumes to >12 km. Major disruptions in air traffic. Ashfalls on Anchorage and the Kenai Peninsula. Dome growth continues into June. Minor steam and ash emissions continue into late 1990.

KISKA Ash and steam plume observed on 1 June. Pilot report of cloud reaching 3.5 km altitude.

AKUTAN Ash and steam plumes erupted from the intracaldera cinder cone to heights of several hundred to 1800 meters above the vent on 6, 21, 22, 30 September and 1 October.

1991

REDOUBT Minor ash emissions from lava dome; fallout confined to summit crater. Declining seismicity. Level of Concern Color Code downgraded to GREEN on 19 April.

AKUTAN Ash and steam plumes reported up to several km over the volcano on 15, 27, 29 September and 11, 13, 14, 18, 19, 30 October.

WESTDAHL Fissure eruption reported 29 November accompanied by ash and steam plume to 7 km. Light ashfall and rumbling heard in False Pass on 9, 12, 16, 26 December. Brief disruption to air traffic. Overflight documented lahar activity in conjunction with early phase of eruption; blocky lava flows steam down canyons on volcano's east flank.

1992

SPURR/CRATER PEAK Following 10 months of premonitory seismicity and a formal AVO warning of unrest, brief explosive eruptions on 27 June, 18 August, 16-17 September send tephra plumes to > 14 km. Air traffic disrupted. Ashfall of 1-3 mm on Anchorage closes International Airport for 20 hours on 18-19 August. Intense seismic swarm accompanies intrusion on 9-10 November.

WESTDAHL Fissure eruption which began on 29 November, 1991, ends in mid-January. Lava flow covers 5 km2 on the northeast flank of Westdahl.

AKUTAN Minor steam and ash emission from intracaldera cinder cone on 8 March continuing through late May; plumes reach a maximum altitude of 4.6 km. Small ash plume to 1.8 km on 18 December.

BOGOSLOF New lava dome, about 90 m high and 350 m across, emplaced at north end of island between 6 and 24 July. Accompanying ash and steam plumes to a maximum of 8 km altitude.

SEGUAM Small ash eruptions from near Pyre Peak send plumes to < 1.2 km altitude on 27 and 30 December.

1993

VENIAMINOF Intermittent minor ash and steam plumes from intracaldera cinder cone beginning 30 July and continuing throughout the year. Light dusting of fine ash on Port Heiden on 4 August. Incandescent material observed over the summit caldera on several occasions at night. New pit melted into summit ice cap adjacent to cone.

SEGUAM Ash burst from vents near Pyre Peak to several km altitude on 28 May, possibly 2 June Activity resumes in late July through late August and includes production of a lava flow.

SPURR/CRATER PEAK Declining seismicity; Level of Concern Color Code downgraded to GREEN on 5 March.

1994

KANAGA Increased steaming from summit crater and upper flank fumaroles first noted on February 17, 1993. Beginning in early January, 1994, minor ash plumes usually less than 1 km over the summit continue intermittently throughout the year. Occasional sulfur smell in Adak. Avalanching of incandescent fragmental debris down the north flank into the sea reported in April. Significant ash plumes to about 7.5 km altitude on 21 February, to about 4.5 km 18-21 August; dusting of ash on Adak on 20 August and disruption of air traffic into Adak on 22 August. AVHRR satellite imagery detects hot spot near Kanaga summit intermittently throughout the year depending on weather conditions. Occasional steam plume sightings over the volcano throughout the year when weather conditions allow.

VENIAMINOF Nearby residents and pilots report intermittent steam and ash bursts < 1 km over volcano throughout the year. Lava flows issuing from the active cinder cone had melted a pit in summit ice cap approximately 1 km across by May. AVHRR satellite imagery detects hot spots in caldera intermittently throughout the year depending on weather conditions. Occasional steam plume sightings over the volcano throughout the year.

CLEVELAND Brief burst of ash to about 10.5 km on May 25. Ashfall confined to northeast flank of the volcano.

SHISHALDIN Pilot report of a possible eruption on 4 October; steam plume to 3 km altitude with minor amounts of ash.

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