The lava dome covering Mount Cleveland volcano in Alaska has grown by 25% since last week. According to the Alaska Volcano Observatory (AVO), the dome was reported to be 40 meters across on Monday Feb. 6., and has now increased to 50 meters in size. The current lava dome is much smaller than the dome was before the last eruption of Mt. Cleveland. The volcano is still at an "orange watch" level (the volcano is exhibiting heightened or escalating unrest with increased potential of eruption) and the timeframe is uncertain, according to the AVO.
The previous lava dome that was removed by explosive activity on Dec. 25 and Dec. 29 covered most of the 200-meter-diameter summit crater implicating that it is larger than the current dome. A larger dome doesn't necessarily mean a larger yield from the explosion according to AVO volcanologists which point that they were still expecting the same type of altitude for the ash cloud. They warn that it should interrupt Trans-Pacific flights.
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There have been no indications of explosive ash-producing activity from distant seismic, pressure or lightning sensors. It remains possible for intermittent, sudden explosions of blocks and ash to occur at any time, and ash clouds exceeding 20,000 feet above sea level may develop. Such explosions and their associated ash clouds may go undetected in satellite imagery for hours. If a large, explosive, ash-producing event occurs, seismic, infrasound, or volcanic lightning may be detected by local and regional monitoring networks. There is no real-time seismic monitoring network on Mount Cleveland.
The new lava dome is still expanding, but when it is finished, it could stay inactive for years. If the volcano erupts, the dome could actually collapse beforehand. The lava dome could become too massive and cave in on itself before an explosion happens.
Symmetrical Mount Cleveland stratovolcano is situated at the western end of the uninhabited dumbbell-shaped Chuginadak Island in the east-central Aleutians. The 1,730-m-high stratovolcano is the highest of the Islands of Four Mountains group and is one of the most active in the Aleutians. Numerous large lava flows descend its flanks. It is possible that some 18th to 19th century eruptions attributed to Carlisle (a volcano located across the Carlisle Pass Strait to the NW) should be ascribed to Cleveland. In 1944 Cleveland produced the only known fatality from an Aleutian eruption. Recent eruptions from Mt. Cleveland have been characterized by short-lived explosive ash emissions, at times accompanied by lava fountaining and lava flows down the flanks. (Global Volcanism Program)
Featured image: Photo by Michelle Harbin, 1994 (courtesy of Alaska Volcano Observatory, U.S. Geological Survey).