Mount Semeru in Lumajang is still experiencing active earthquakes due to its eruption.

LUMAJANG, East Java – The 3,676-metre Mount Semeru in Lumajang Regency, East Java, is still actively producing earthquakes due to its eruption.

“During the seismic observation period from 00.00 to 24.00 WIB on Thursday (4/7), 159 eruption earthquakes with amplitudes ranging from 10 to 22 mm and seismic durations ranging from 55 to 132 seconds were recorded on Mount Semeru,” said Mukdas Sophian, director of Mount Semeru Observatory, in a written statement received in Lumajang, Friday.

According to him, 12 avalanche earthquakes with amplitudes ranging from 2 to 8 mm and durations ranging from 32 to 78 seconds occurred in the mountains on the border of Lumajang regency and Malang.

“Furthermore, 12 gust earthquakes with amplitudes ranging from 3 to 8 mm and seismic durations ranging from 28 to 74 seconds were recorded, followed by six distant tectonic earthquakes with amplitudes ranging from 16 to 40 mm,” he said.

Heavy rainfall on the summit of Java’s highest mountain also caused a flood shaking earthquake to be recorded on Mount Semeru, with an amplitude of 10mm and a seismic duration of 2,026 seconds.

Meanwhile, Hendra Gunawan, director of the Centre for Volcanology and Geological Hazard Mitigation (PVMBG), said authorities were assessing Mount Semeru’s activity in stages.

“Based on the results of comprehensive analysis and evaluation up to June 30, 2024, the activity level for Mount Semeru remains at Level III or Alert Level and recommendations are adjusted to the current hazard threat,” he said.

He said the party had advised the public not to carry out any activities in the southeast, within 13 kilometres of the summit of Mount Besuk Cobokan – the epicentre of the eruption.

Moreover, people are also advised to avoid any activities within 500 metres of the river bank (river boundary) along the Besuk Cobokan, as outside that distance, hot cloud expansion and lava flows could strike up to a distance of 17 kilometres from the summit, he said.

Residents are also prohibited from engaging in any activities within a 5 km radius of Mount Semeru’s crater/summit due to the risk of exhalative rocks (incandescent rocks).

The public is also urged to be on the lookout for possible hot clouds, lava avalanches and lava in the rivers and valleys that originate from the summit of Mount Semeru, especially along Besuk Kobokan, Besuk Bang, Besuk Kembar and Besuk Sat, as well as the possibility of lava in the streams that are tributaries of Besuk Kobokan.


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