Chandra Adi Nurwidya, Central Java – Mount Merapi in Indonesia's Central Java province released a pyroclastic flow on Saturday morning, sending hot volcanic material about 2 kilometers (1.2 miles) down the mountain's southwestern slope toward the upper reaches of the Sat and Putih rivers.

The Geological Disaster Technology Research and Development Center (BPPTKG) said the pyroclastic flow occurred at 9:18 a.m. local time (0218 GMT).

BPPTKG head Agus Budi Santoso said monitoring equipment recorded a maximum amplitude of 31.9 millimeters, with the event lasting 142.28 seconds.

"The estimated runout distance was 2,000 meters toward the southwest, into the upper Sat/Putih river areas," Agus said.

Mount Merapi, one of Indonesia's most active volcanoes, remains at Alert Level III, or "Siaga," the third-highest level in the country's four-tier volcanic alert system.

Authorities have urged residents and visitors to avoid designated hazard zones around the volcano.

On the southern and southwestern sides, lava flows and pyroclastic flows could reach up to 5 kilometers along the Boyong River and up to 7 kilometers along the Bedog, Krasak and Bebeng rivers.

On the southeastern side, the Woro River is considered at risk for up to 3 kilometers, while the Gendol River could be affected for up to 5 kilometers.

In the event of an explosive eruption, volcanic material could be ejected up to 3 kilometers from the summit, according to BPPTKG.

Monitoring has also detected continued magma supply beneath the volcano, which could trigger further pyroclastic flows within the designated hazard zones.

"People are urged to stay away from hazardous areas and river channels originating on Mount Merapi and to follow official recommendations," Agus said.

Authorities have also warned residents to be alert for lahars and further pyroclastic flows, particularly during rainfall around the volcano. Volcanic ash from ongoing activity could also disrupt communities and activities in surrounding areas.

BPPTKG said Merapi's activity level would be reviewed if there were significant changes in its volcanic activity.

Mount Merapi, which rises to about 2,910 meters above sea level, is located on the border between Central Java and Yogyakarta and is closely monitored because of its frequent eruptions and dense population in surrounding areas.

Source: https://jakartaglobe.id/news/mount-merapi-erupts-sends-pyroclastic-flow-2-kilometer