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Report on Semeru (Indonesia) — 30 March-5 April 2022


Semeru

Smithsonian / US Geological Survey Weekly Volcanic Activity Report,
30 March-5 April 2022
Managing Editor: Sally Kuhn Sennert

Please cite this report as:

Global Volcanism Program, 2022. Report on Semeru (Indonesia). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 30 March-5 April 2022. Smithsonian Institution and US Geological Survey.

Weekly Report (30 March-5 April 2022)

Semeru

Indonesia

8.108°S, 112.922°E; summit elev. 3657 m

All times are local (unless otherwise noted)


PVMBG reported that the eruption at Semeru continued during 25-31 March. Activity included a pyroclastic flow, ash plumes that rose 300-700 m and drifted mainly N and NW, and gas-and-steam emissions reaching 200-300 m above the summit. Ground observers, webcam images, and satellite data detected ash plumes that rose to 4.3 km (14,000 ft) a.s.l. and drifted N and W, according to MAGMA Indonesia and the Darwin VAAC. Avalanches were reported on 1 April. On 3 April a strong thermal anomaly was detected in infrared satellite imagery. The Alert Level remained at 3 (on a scale of 1-4). The public was warned to stay at least 500 m away from Kobokan drainages within 17 km of the summit, along with other drainages originating on Semeru, 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.

Sources: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM), Darwin Volcanic Ash Advisory Centre (VAAC)