A new explosion was detected on Alaska's Cleveland volcano on April 4, 2018, prompting authorities to raise the Alert Level to Watch and the Aviation Color Code to Orange.
It was a small explosion, detected using local seismic and infrasound sensors at 11:55 UTC today, the Alaska Volcano Observatory said.
Explosions from Cleveland typically produce relatively small volcanic ash clouds that dissipate within hours. No ash cloud from this event has been seen in satellite images, which currently are partly obscured by weather clouds, AVO added.
Cleveland volcano is monitored with a limited real-time seismic network, which inhibits AVO's ability to detect precursory unrest that may lead to an explosive eruption. Rapid detection of an ash-producing eruption may be possible using a combination of seismic, infrasound, lightning, and satellite data.
Its most recent significant period of eruption began in February 2001 and produced 3 explosive events that generated ash clouds as high as 11.9 km (39 000 feet) above sea level. The 2001 eruption also produced a lava flow and hot avalanche that reached the sea.
Since then, Cleveland has been intermittently active producing small lava flows, often followed by explosions that generate small ash clouds generally below 6 km (20 000 feet) above sea level. These explosions also launch debris onto the slopes of the cone producing hot pyroclastic avalanches and lahars that sometimes reach the coastline.
Beautifully symmetrical Mount Cleveland stratovolcano is situated at the western end of the uninhabited, dumbbell-shaped Chuginadak Island. It lies SE across Carlisle Pass strait from Carlisle volcano and NE across Chuginadak Pass strait from Herbert volcano.
Cleveland is joined to the rest of Chuginadak Island by a low isthmus. The 1730-m-high (5 675 feet) Mount Cleveland is the highest of the Islands of the Four Mountains group and is one of the most active of the Aleutian Islands. The native name for Mount Cleveland, Chuginadak, refers to the Aleut goddess of fire, who was thought to reside on the volcano.
Numerous large lava flows descend the steep-sided flanks. It is possible that some 18th-to-19th century eruptions attributed to Carlisle should be ascribed to Cleveland (Miller et al., 1998).
In 1944 Cleveland produced the only known fatality from an Aleutian eruption. Recent eruptions have been characterized by short-lived explosive ash emissions, at times accompanied by lava fountaining and lava flows down the flanks. (GVP)
Featured image: From right to left - Tana, Cleveland and Herbert volcanoes, viewed from sunny Concord Point (southeast shore of Chuginadak Island), July 26, 2016. Credit: John Lyons, AVO/USGS.