US observatory lowers aviation warning after Alaska volcano eruption

The Alaska Volcano Observatory Saturday lowered the Aviation Color Code to orange as there was no detectable activity observed in seismic, infrasound or lightning data from a volcano in the Aleutian Islands.

Bogoslof Volcano, about 1,370 km southwest of Anchorage, the biggest city in Alaska, began to erupt Friday morning and sent a cloud of ash and ice particles up to 9,140 meters, or 30,000 feet in the air, prompting the volcano observatory to raise the warning level to red.

With summit elevation of 150 meters, or 492 feet, the volcano on Bogoslof Island along the southern edge of the Bering Sea has erupted more than 25 times since mid-December 2016.

Located 56 km northwest of Unalaska Island, home to one of the largest fishing ports in the United States, Bogoslof Island has a land area of 0.68 square kilometer, or 169 acres, and is uninhabited by people.

The volcano observatory said the volcanic cloud from the eruption had dissipated and no further ash emissions have occurred at Bogoslof volcano.

However, it noted that significant ash-producing explosions could occur at any time with no detectable precursors and low-level activity below its detection limit is possible and may present a hazard in the immediate vicinity of the island. 

source: Xinhua