Alaska's Cleveland Volcano is on orange alert again after elevated temperatures were detected in satellite images at the end of January, the Alaska Volcano Observatory (AVO) reported on Wednesday. Cleveland Volcano forms the western half of Chuginadak Island, located in the Aleutians Islands chain west of Dutch Harbor. The nearest occupied village is Nikolski, roughly 60 miles away.
Chris Waythomas, the acting scientist in charge at the USGS observatory, said Cleveland Volcano is "likely one of the most active" in the state. But because of its remote location "we're not sure exactly" just how active it is. Scientists use satellite imagery and seismic data to monitor the volcano. There is also an infrasound lab in Dillingham run by the University of Alaska that can pick up unusual airwaves caused by an explosion.
Satellite data obtained on Jan. 30 show a lava dome had formed in the summit crater as early as Jan. 24. A lava dome is formed when magma generated deep below the crater travels to the surface. Cleveland is a "very open system," Waythomas said, meaning magma bubbles up to the surface relatively easily. Sometimes when lava domes form, they plug the volcano's conduits and prevent ventilation, which in turn causes an explosion.
If a large event were to take place at Cleveland, ash could spread toward Dutch Harbor, the closest town with a sizable population. Ash clouds higher than 20,000 feet are also a concern for airplanes and jets traveling through the area. Waythomas said 200 to 300 aircraft fly the North Pacific air route daily, and they would "definitely want to know" if there were ash in the air.
An ash burst could also cause volcanic lightning, a result of static electricity created by the mingling of ash and clouds.
The last time Cleveland was put on Orange alert was Nov. 10 last year. The most recent major explosion was in 2001, when three explosions produced ash clouds up to 39,000 feet and a lava flow that reached the sea.
On Thursday, cloud cover over the volcano prevented AVO from monitoring changes to its activity; it remains in orange alert watch status.
Contact Laurel Andrews at laurel(at)alaskadispatch.com