DRAMATIC footage shows the moment Mount Semeru erupted - sending avalanches of 700C ash into the air.
It comes just one year after at least 50 people were killed when the same volcano in Indonesia's main island Java exploded.
Almost 2,000 people have been evacuated after the volcano - also known as "The Great Mountain" - again blew its top.
One clip of the huge eruption showed an "avalanche" of 704C ash crashing into a series of valleys.
Other incredible footage shows plumes of smoke spewing 50,000 ft into the air.
Burning hot ash clouds had drifted almost 19 km from the centre of the eruption, according to Indonesia's Center for Volcanology and Geological Hazard Mitigation (PVMBG).
No injuries have been reported since the explosion at 2.46am local time (7.46pm on Saturday GMT), but people have been warned to stay at least 8km away as authorities raised the alert level to its highest.
Pictures show rescuer workers frantically help evacuate people from the area.
The eruption, some 640km east of the capital, Jakarta, follows a series of earthquakes in the west of Java, including one last month that killed more than 300 people.
PVMBG chief Hendra Gunawan said a bigger volume of magma could have built up compared with previous eruptions of the volcano, in 2021 and 2020, which could mean greater danger for a bigger area.
He said: "Semeru's hot clouds could reach further and at a distance where there are many residences".
The Gladak Perak Bridge, which was rebuilt last year after last year's eruption, was building damaged in the blast while images show the aftermath of the burnt landscape.
Semeru, the tallest mountain on Java at 12,060ft, erupted last year killing more than 50 people and displacing thousands.
With 142 volcanoes, Indonesia has the world's largest population living close range to volcano, with 8.6 million people within 10km of one.
It comes just days after stunning photos showed Mauna Loa - the biggest active volcano in the world - shooting out lava in its first eruption in almost 40 years.
The night sky in Hawaii burned reddish orange as the volcano began spewing lava for the first time since 1984.
