Lava flow from a volcanic explosion in the remote north-eastern region of Afar in Ethiopia covers a record area. Satellite photos show the lava covers about 300 square kilometres.
According to Addis Ababa University, the eruption on Monday prompted a minor earthquake, but there were no reported injuries or damage to infrastructure.
Thousands of people were displaced when Mount Erta Ale erupted in 2005.
It is in the Danakil Depression, known for its salt mines and one of the lowest and hottest places on earth.