Which Five Indonesian Volcanoes Are Showing Increased Activity? Anak Krakatau Among Them

Five Indonesian volcanoes have erupted or shown significant activity in recent days, prompting authorities to monitor danger zones and warn residents and visitors to keep their distance.

The volcanoes are Anak Krakatau, Mount Ibu, Mount Sinabung, Mount Semeru and Mount Lewotobi Laki-Laki. Reported hazards range from ash emissions and eruptions to possible pyroclastic flows and lava avalanches.

Anak Krakatau, in the Sunda Strait, erupted on the night of September 4, with continuous eruptions continuing until early September 6. The Center for Volcanology and Geological Hazard Mitigation recorded a Strombolian-type eruption at 3:53 a.m. on September 6 that lasted about 30 seconds. The agency tentatively interpreted it as the end of the preceding continuous eruption episode.

The volcano remained at Level III, or Alert. Authorities advised the public, tourists and hikers not to enter within three kilometres of its center of activity. Monitoring showed a brief increase in seismic amplitude on September 5, while tiltmeter data from Tanjung Station continued to show inflation observed since early August.

Mount Ibu, in North Maluku, erupted at 10:04 a.m. on September 6, sending an ash column about 600 metres above the summit. The volcano remained at Level II, or Advisory. PVMBG advised people to avoid a two-kilometre radius around the crater and a sector extending 3.5 kilometres toward the crater opening. It also recommended masks and eye protection if ash fell.

Mount Sinabung in North Sumatra was raised to Level III at noon on September 6. The supplied report also identifies Mount Semeru and Mount Lewotobi Laki-Laki among the volcanoes under close monitoring.