World’s largest active volcano erupts

The world’s largest active volcano, Mauna Loa on Hawaii, is erupting for the first time in nearly 40 years.

On Monday, the US Geological Service (USGS) said the situation could change rapidly.

It erupted at 23:30 local time on Sunday (09:30 GMT Monday) at Moku'āweoweo, the volcano's summit caldera. Calderas are hollows that form beneath the summit at the end of an eruption.

Mauna Loa, located inside Hawaii Volcanoes National Park, covers half of the US state's Big Island. The volcano rises 13,679ft (4,169m) above sea level and spans an area of more than 2,000 sq miles (5,179 sq km).

Though lava is flowing down one side of the volcano, the eruption in Hawaii Volcanoes National Park is not threatening communities, it said.

The volcano's alert level has also been upgraded from an "advisory" to a "warning" - the highest classification.

No evacuation orders have been issued and populated areas are unlikely to be impacted at this stage, emergency officials say.

"Based on past events, the early stages of a Mauna Loa eruption can be very dynamic and the location and advance of lava flows can change rapidly," the USGS said.