Report on Semeru (Indonesia) — 27 March-2 April 2024
Smithsonian Institution / US Geological Survey
Weekly Volcanic Activity Report, 27 March-2 April 2024
Managing Editor: Sally Sennert.
Please cite this report as:
Global Volcanism Program, 2024. Report on Semeru (Indonesia) (Sennert, S, ed.). Weekly Volcanic Activity Report, 27 March-2 April 2024. Smithsonian Institution and US Geological Survey.
Semeru
Indonesia
8.108°S, 112.922°E; summit elev. 3657 m
All times are local (unless otherwise noted)
PVMBG reported that eruptive activity continued at Semeru during 27 March-2 April. Eruptive events were recorded during 27 March and 1-2 April by the seismic network, though emissions were not observed due to darkness or weather conditions. According to a news article the Mount Semeru Observation Post officer reported that an eruption occurred at 1518 on 28 March but not visually observed; seismicity indicated that pyroclastic flows descended the flanks for about 27 minutes. White-and-gray ash plumes rose 500-800 m above the summit and drifted N, W, SW, and S during 28-31 March. The Alert Level remained at 3 (the third highest level on a scale of 1-4). The public was warned to stay at least 5 km away from the summit in all directions, 13 km from the summit to the SE, 500 m from the banks of the Kobokan drainage as far as 17 km from the summit, and to avoid other drainages including the Bang, Kembar, and Sat, due to lahar, avalanche, and pyroclastic flow hazards.
Geological Summary. Semeru, the highest volcano on Java, and one of its most active, lies at the southern end of a volcanic massif extending north to the Tengger caldera. The steep-sided volcano, also referred to as Mahameru (Great Mountain), rises above coastal plains to the south. Gunung Semeru was constructed south of the overlapping Ajek-ajek and Jambangan calderas. A line of lake-filled maars was constructed along a N-S trend cutting through the summit, and cinder cones and lava domes occupy the eastern and NE flanks. Summit topography is complicated by the shifting of craters from NW to SE. Frequent 19th and 20th century eruptions were dominated by small-to-moderate explosions from the summit crater, with occasional lava flows and larger explosive eruptions accompanied by pyroclastic flows that have reached the lower flanks of the volcano.
Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)