|Start:||July 14, 1990 ||Observed|
|Fumarolic or hydrothermal activity: ||
|Eruption Type:||Not an eruption.|
Steam plumes were observed at Mt. Hague on July 14, 1990. This activity probably does not constitute a volcanic eruption.
From Smithsonian Institution (1990): "On 14 July at about 2100, Richard Mack observed and photographed a white plume that had risen 350-500 m from the SW side of the summit crater of Mt. Hague, near the E margin of Emmons Lake Caldera. A series of pulses slowly diminished in size until sunset at about 2200. Traces of material trailed SSW from the top of the plume.
"Mack stated that he had not seen such activity during his 57 years on the Alaska Peninsula. However, during fieldwork in 1946, Kennedy and Waldron (1955) observed six large fumaroles and many other small ones in a steep gully on the SW side of Mt. Hague, at altitudes of ~975-1,150 m. They did not give plume heights, but reported clouds of SO2 and steam rising from the major vents, with a locomotive-like noise that was audible ½ km away. The volume of sulfur fumes prevented the geologists from approaching nearer than roughly 100 m from the vents. Sulfur odors were strong many kilometers downwind. Sulfur cones ~1 m high had developed around the vents and extensive deposits of native sulfur were found in the gully. Miller (in Wood and Kienle, 1990) also reported a large fumarolic area on the S side of Mt. Hague."
From Reeder (1993): "At about 2100 on July 14, 1990, Richard Mack of King Cove observed an eruption plume of smoke (steam with ash or with at least particulate matter) that had just risen at least 500 m (based on photographs, estimated to have risen about 600 m) above the crater rim from the very SW inner side of the summit crater of Mount Hague. * * * The plume emission location was determined by J. Reeder based on photographs, air photographs, and 1:63,360 U.S.G.S. topographic maps to be 55 degrees 22 minutes 21 seconds N, 161 degrees, 58 minutes, 43.3 seconds W. Traces of particulate matter and/or tephra trailed to SSW from the top of the plume beyond the shore of the Pacific Ocean from the previous apparently continuous emissions from the summit crater. The emission was fairly continuous, as represented by a series of belches that slowly decreased in size by the time the sun had gone down just before 2200. Richard made his observations from his fishing boat on the S part of Pavlof Bay just SW of Bluff Point along Long Beach.
"Richard Mack noted some emissions from the same point of Mount Hague during the next morning (July 15), but due to strong winds the emissions did not rise to form impressive plumes like the evening before. But, the emissions were there. Richard then left the region."