"Avalanches of incandescent lava occurred for 10 times, with a maximum sliding distance of 1,000 meters to the southwest or upstream of Krasak and Boyong Rivers," Head of BPPTKG Hanik Humaida said here on Sunday morning.
During the observation period of midnight until 6 a.m., Mount Merapi also experienced 27 earthquake avalanches with an amplitude of 3-11 mm for 11.4-52.2 seconds and two multi-phase earthquakes with an amplitude of 6 mm for 7.6-9.4 seconds.
During Saturday's observation period at 18.00 until 24.00 local time, Mount Merapi had launched incandescent lava avalanches for 12 times, with a maximum sliding distance of 1,200 meters to the southwest.
The BPPTKG maintains the status of Mount Merapi at Level III or Alert.
Potential hazards due to lava avalanches and hot clouds are estimated to cover the south-southwest sector, which includes the Boyong, Bedog, Krasak and Bebeng rivers.
The 2,968-meter Mount Merapi is the most active among the around 130 active volcanoes in the country.
In the meantime, the 3,676-meter Mount Semeru in East Java Province has also been erupting for several times since January this year, displacing hundreds of people and affecting several villages with volcanic ash rains.