Update on Anak Krakatau After Successive Eruptions on Friday
Gunung Anak Krakatau (GAK) in the Sunda Strait experienced successive eruptions on Friday (10/7). The Centre for Volcanology and Geological Hazard Mitigation (PVMBG) recorded the volcano erupting four times within approximately one hour on Friday afternoon. The volcano currently remains at Level III (Siaga) alert status.
According to the daily report on the magma.esdm.go.id website for today, Saturday (11/7), during the monitoring period from 06:00 to 12:00, the volcano’s condition was observed to be covered in fog. ‘The volcano was clearly visible until it became covered in fog 0-III. White main crater smoke was observed with moderate to thick intensity, reaching a height of about 20-50 metres from the summit,’ the site reported. ‘The weather is sunny, with a weak wind blowing towards the northwest,’ it continued. The report also noted, ‘Sea waves are calm to moderate.’
Seismic observations in the daily report for GAK recorded ‘4 emission earthquakes with amplitudes of 13-22 mm and earthquake durations of 22-75 seconds.’ It also reported ‘4 low-frequency earthquakes with amplitudes of 11-21 mm and durations of 5-7 seconds; 5 hybrid/multi-phase earthquakes with amplitudes of 10-24 mm, S-P not observed, and durations of 7-22 seconds.’ Additionally, ‘1 continuous tremor earthquake with an amplitude of 2-15 mm, dominant at 3 mm.’
The observing officer’s daily report urged, ‘The public, visitors, tourists, and hikers should not approach Mount Anak Krakatau or conduct activities within a 3-kilometre radius of the active crater.’
On Friday evening, a series of eruptions occurred. The first eruption took place at 16:42 WIB, producing an ash column 250 metres high above the summit. Volcanic activity was recorded again at 16:57 WIB, with an ash column reaching 200 metres. An eruption was then recorded at 17:49 WIB, with an ash column height of around 100 metres. Two minutes later, at 17:51 WIB, Mount Anak Krakatau again spewed volcanic ash up to 200 metres above the peak. Based on PVMBG observations, all ash columns were black with thick intensity and moved towards the north, northeast, and northwest. The series of eruptions was also recorded on a seismograph with a maximum amplitude of 43 to 55.2 millimetres and a duration between 33 and 49 seconds.
Andi Suwardi, Head of the Mount Anak Krakatau Observation Post in South Lampung, stated that volcanic activity remains fluctuating, but the volcano’s status is still at Level III (Siaga). PVMBG confirmed that monitoring of Mount Anak Krakatau’s activity continues intensively. The public is urged to follow official information from volcanology authorities and not to easily trust unverified reports.