Indonesia's most dangerous volcano has forced international airlines to cancel flights to nearby airports due to a slow eruption which scientists have warned could continue for weeks.
No casualties have been reported in Mount Merapi's latest blasts, which came as Indonesia struggled to respond to an earthquake-generated tsunami that devastated a remote chain of islands.
Merapi has killed 38 people in the last week, bringing the combined death toll from the two disasters to nearly 470 people.
Malaysian budget airline AirAsia and Singapore's SilkAir have suspended several international flights to Yogyakarta and Solo, both within 20 miles of the crater.
There have been more than 10 large eruptions at Merapi since the first big explosion on October 26; and almost 70,000 villagers have been evacuated from its surrounding area.
They have been told they could be expected to stay in crowded government camps for at least three more weeks.
Elsewhere in Indonesia, a C-130 transport plane, six helicopters and four boats were ferrying aid to the Mentawai islands, where last week's tsunami destroyed hundreds of homes, schools, churches and mosques.
The tsunami death toll stood at 431 on Monday, the National Disaster Management Agency said.
President Susilo Bambang Yudhoyono said relief efforts must be sped up, expressing dismay that it took days for aid to reach the isolated islands, though he acknowledged that violent storms were largely to blame.
Indonesia is prone to earthquakes and volcanoes because it sits along the Pacific "Ring of Fire," a horseshoe-shaped string of faults that lines the Pacific.