Mount Semeru in Lumajang, East Java, erupted early Friday morning, spewing a column of ash and smoke at least 400 meters high.
“Our seismograph recorded a two-minute-and-nine-second-long eruption with a maximum amplitude of 25 millimeters,” said the head of the Center of Volcanology and Geological Hazard Mitigation (PVMBG) Mitigation Unit, Hendra Gunawan, as quoted by Antara news agency.
According to Hendra, the mountain was spewing out a column of ash at moderate intensity in a northeasterly direction.
"The eruption was accompanied by 17 earthquakes with amplitudes of 10 to 23 mm. The earthquakes' duration was 56 to 130 seconds," he said.
The PVMBG also recorded a 75-second-long tectonic earthquake with a 3-mm amplitude and six earthquakes with durations of 10 to 105 seconds at amplitudes of 3 to 9 mm.
Hendra said that eruptions often happened at Mt. Semeru since it was an active volcano. He said the eruption would only impact areas around the mountain's peak. "The mountain's alert level is still at the caution level, or level II, so visitors and climbers alike are not allowed to conduct any activity within a 1-km radius and a 4-km radius from the south or the southeastern area of the active crater," he said.
He added that the PVMBG recommended the public to be careful since the Jongring Seloko crater dome could fall in at times.
Meanwhile, the head of the Disaster and Mitigation Agency's Logistics and Prevention Unit, M. Wawan Hadi Siswoyo, said his team had already received information regarding the eruption from a volcano monitoring post at Mount Sawur Lumajang.
"People who live on the [Semeru] mountain slope are already used to any sort of volcanic activity, including eruptions. However, we will remind the public to follow the PVMBG's recommendations," he added. (dpk)