PVMBG reported that an explosive eruption at Marapi began at 0611 on 7 January, generating a dense white-and-gray ash plume that rose 300 m above the summit and drifted SE. Images posted with the report showed jets of dark material rising from the crater. Emissions continued to periodically rise form the crater; at 0944, 1034, and 1451 dense white or white-to-gray ash plumes rose 200-250 m above the summit and drifted SE. Seismic signals indicated that eruptive events also occurred at 1135, 1144, 1230, 1715, and 1821, but no ash emissions were visually observed. At 1250 on 8 January a dense white ash plume rose 150 m and drifted SE and at 1300 a dense white-to-gray ash plume rose 200 m and drifted E. Seismic signals indicated eruptive events at 0447, 1038, and 1145, but again no ash emissions were visually observed. At 0634 on 9 January a dense white ash plume rose around 250 m and drifted E and SE. The eruption was preceded by an increase in the number of deep volcanic earthquakes beginning on 25 December 2022 and summit inflation. The Alert Level remained at 2 (on a scale of 1-4).

Geological Summary. Gunung Marapi, not to be confused with the better-known Merapi volcano on Java, is Sumatra's most active volcano. This massive complex stratovolcano rises 2,000 m above the Bukittinggi Plain in the Padang Highlands. A broad summit contains multiple partially overlapping summit craters constructed within the small 1.4-km-wide Bancah caldera. The summit craters are located along an ENE-WSW line, with volcanism migrating to the west. More than 50 eruptions, typically consisting of small-to-moderate explosive activity, have been recorded since the end of the 18th century; no lava flows outside the summit craters have been reported in historical time.

Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)