A high-level eruption occurred at Indonesia’s Semeru volcano on December 4, 2022, prompting authorities to raise the Alert Level from III to IV — the highest. The last major eruption at this volcano took place on December 4, 2021, leaving 51 people dead and several hundred others injured.
VONA issued by the Semeru Volcano Observatory at 02:18 UTC today indicated eruption to 8.6 km (28 000 feet) above sea level, but IR temperature of -66 °C (-86.8 °F) indicated eruption is significantly higher to 15.2 km (50 000 feet) a.s.l., moving SW, according to the Darwin VAAC VA Advisory issued at 03:05 UTC.1
The Aviation Color Code was raised to Red.
Volcanic ash is currently obscured by meteorological clouds but the eruption is expected to be ongoing based on ground reports and webcam. Ash cloud was observed reaching 15.2 km (50 000 feet) in Himawari-8 satellite imagery at 05:00 UTC, Darwin VAAC said at 09:15 UTC.
Several hundred people living near the volcano were evacuated to temporary shelters or other safe areas. Authorities advised everyone to stay away 8 km (5 miles) from the crater and avoid the southeastern sector area along the Besuk Kobokan river located about 13 km (8 miles) from the crater.
There have been no reports of injuries or deaths so far.
Several villages were blanketed in sun-blocking ash.
Japan’s Meteorological Agency said it’s monitoring for the possibility of a tsunami after the eruption.
The current eruptive episode at the volcano began in April 2014 – (VEI 4).
On December 4, 2021, a high-level eruption to 15.2 km (50 000 feet) a.s.l. left 51 people dead and several hundred others injured with serious burns. More than 10 000 people were forced to evacuate. Nearly 3 000 houses and 38 schools were damaged.2
Update
December 5
Hundreds of rescuers were deployed on Monday, December 5 in the worst-hit villages of Sumberwuluh and Supiturang, where houses and mosques were buried to their rooftops by tons of volcanic debris.3
The pyroclastic flow produced by the eruption destroyed a bridge that had just been rebuilt after a powerful eruption in December 2021.
Lumajang district chief Thoriqul Haq said nearly 2 000 people escaped to emergency shelters at several schools, but many returned to their homes Monday to tend their livestock and protect their property.
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.
This volcano is located within the Bromo Tengger Semeru-Arjuno, a UNESCO Biosphere Reserve property.4
1 Darwin VAAC VA Advisories – December 4, 2022
2 At least 39 killed, 12 missing and 57 injured after massive eruption at Semeru volcano, Indonesia – The Watchers – December 4, 2021
3 Indonesia’s Mt. Semeru eruption buries homes, damages bridge – AP – December 5, 2022
4 Semeru – Geological summary – GVP
