A stream of lava flowed down the side of the Great Sitkin volcano in the Aleutian Islands Thursday morning and was visible from the nearby community of Adak, an official with the Alaska Volcano Observatory said.
Meanwhile, minor clouds of ash spewed from the Alaska Peninsula Pavlof volcano and the Aleutian Islands Semisopochnoi volcano.
No communities were immediately impacted by the volcanic activity.
The Great Sitkin volcano, which is located along the Aleutian chain about 26 miles east of Adak, has experienced unrest for about the last two weeks, said Chris Waythomas, a geologist for the USGS.
“There’s been a lava accumulation growing above the active vent, so there’s a small crater of the active area and lava is coming out of that and it’s forming this dome-shaped accumulation of lava,” he said.
“This morning, clear views from Adak and on the island indicated some minor lava fountaining happening at the summit,” he said.
Waythomas described the eruption as a “Hawaiian-style ejections of incandescent material maybe 50 to 100 meters above the vent.”
A volcanic cloud has since formed over the volcano, but Waythomas said it’s mostly made from water vapor and gas. The cloud was not composed of dense ash Thursday afternoon and Waythomas said he did not expect it to immediately impact Adak or aviation in the area.
The volcano was in an orange code warning Thursday and Waythomas said it could switch to red if the eruption becomes more explosive or produces a significant cloud of ash. Volcanoes, he said, are highly unpredictable, but for now Great Sitkin is not showing any signs that would signal a larger eruption.
The lava could continue to spout off intermittently throughout the next few months, Waythomas said.
“It might start and stop,” he said. “It just depends on how much magma is involved. From the information that we’ve got, it doesn’t appear that there’s lots of magma involved, so we don’t think it’ll go on for decades or anything like that, but it could go on for some months yet.”
The volcano erupted briefly in May, spewing ash 15,000 feet high. But the Great Sitkin had not erupted since 1974 before then.
A minor cloud of ash also spewed from Pavlof volcano around 8 a.m. Thursday, Waythomas said. The volcano is located on the Alaska Peninsula and is about 37 miles northeast of Cold Bay and 600 miles southwest of Anchorage.
The Pavlof volcano spewed ash for about an hour, Waythomas said.
The volcano is one of the most active in the state and Waythomas said it would not be surprising for conditions to continue to escalate. The last eruption happened in 2016 and Waythomas said there is generally an eruption every few years. Pavlof is known for erupting with little notice, he said.
Officials are monitoring the volcano for further activity, Waythomas said.
Another Aleutian volcano, Semisopochnoi, released steam and ash clouds Wednesday night, but the remote volcano is far from any communities and in an area without much air traffic, Waythomas said. Semisophochnoi Volcano is located on an isolated island on the western end of the Aleutian Islands and is about 160 miles west of Adak.