Sunda Strait Earthquake, Mount Anak Krakatau Activity Increases
A magnitude 5.3 earthquake shook the Sunda Strait region in Banten at around 02:44 WIB on Wednesday (8/7). The Meteorology, Climatology and Geophysics Agency (BMKG) recorded the epicentre 62 kilometres southwest of Sumur, Banten. Tsunami modelling results indicate that this earthquake did not pose a tsunami risk.
‘Taking into account the epicentre location and the hypocentre depth, the earthquake that occurred is a shallow earthquake due to subduction activity. The source mechanism analysis shows that the earthquake had an upward movement mechanism,’ stated an official BMKG release. As of 03:05 WIB, BMKG monitoring had not shown any aftershock activity. The public was urged to remain calm and not be influenced by unverified issues, and to avoid buildings that are cracked or damaged due to the earthquake.
Meanwhile, Mount Anak Krakatau erupted repeatedly. Based on data from the Magma Indonesia application, managed by the Ministry of Energy and Mineral Resources’ PVMBG, the volcano in the Sunda Strait erupted five times since the early hours. Monitoring reports show that between 00:00 WIB and 06:00 WIB, Mount Anak Krakatau erupted several times with amplitudes ranging from 24.4 to 26.1 mm. The first eruption occurred at 00:11 WIB, with the ash column height unobserved due to darkness. The seismogram recorded a maximum amplitude of 24 mm for 40 seconds. The eruption continued at 05:50 WIB, with a column height reaching 250 metres, grey to black ash drifting northwest, and a maximum amplitude of 26.1 mm for 44 seconds. Another eruption at 07:11 WIB recorded a 250-metre ash column, grey to black, with a maximum amplitude of 44.4 mm for 31 seconds. An eruption at 08:42 WIB saw the column height decrease to 100 metres above the summit, with thick black ash moving northwest and a maximum amplitude of 35 mm for 40 seconds. Mount Anak Krakatau erupted again at 09:35 WIB, with a column height of 200 metres above the summit, grey ash drifting northwest, and a maximum amplitude of 49 mm for 27 seconds. The GAK observation post in Pasauran Anyar, Serang Regency, Banten, maintains the volcano’s status at Level III (Alert), with a prohibition on activities within a 3-kilometre radius of the active crater.