Merapi phreatic eruption caused rumbling with medium to strong pressure and height of 5,500 meters from the top of the crater. The eruption threw volcanic ash, sand and pyroclastic material.
"The eruption took place suddenly. It was a phreatic eruption that was triggered by a boost of water vapor pressure due to the contact of water masses with heat under the crater of Mount Merapi," Nugroho said in a statement received by Antara on Friday.
According to him, this type of eruption is harmless and can happen anytime on active volcanoes. It usually lasts only for a moment.
"The status of Mount Merapi to date is still normal (Level I) with dangerous radius is three kilometers from the top of the crater. The Volcanology and Geological Disaster Mitigation Center (PVMBG) does not raise the status of Mount Merapi and still keep monitoring the development of volcanic activities," he said.
Nugroho urged the residents living near the Merapi to remain calm, as there have been no reports of casualties.
Sleman Disaster Mitigation Agency (BPBD) has instructed people living within a five kilometers radius to be evacuated in three refugee barracks of Cangkringan, Glagaharjo and Umbulharjo. People responded by conducting self-evacuation to the safe places.
The agency has also distributed mask to prevent people from inhaling harmful substances from volcanic ash rain which expected to fall in the south of Merapi, or depending on the direction of the wind.
"Volcanic ash rain were found in Kaliurang, Yogyakarta. BNPB posts are continuously coordinating with PVMBG and BPBD to handle this situation," Nugroho said.
Reporter: Victorianus Sat Pranyoto/ Luqm
Editor: Bambang Purwanto
Copyright © ANTARA 2018
