Cold Semeru lava slithers through residential areas

Mount Semeru, cold lava
Mount Semeru’s cold lava flows. Photo: DOC. DISPEN KORMAR

IO – Volcanic Mount Semeru, recently raised to alert level 3, spewed hot clouds again on Sunday (1/16/2022).

The hot clouds glided down as far as 4,000 meters from the peak of Semeru, known as the highest mountain on Java, standing 3,676 meters above sea level.

Heavy rains that flushed the mountaintop following the hot clouds triggered flows of cold lava, or lahar dingin, inundating several drainage basins in the Lumajang region. Floods mixed with cold lava swiftly flowed from upstream of Curah Kobokan River into several catchment areas in South Kebondeli Hamlet and Kamar Kajang Hamlet in Sumber Wuluh Village, Candipuro sub-district.

The cold lava flows from Mount Semeru were exacerbated by heavy precipitation in the Lumajang Regency, East Java, Monday (1/17/2022) from the afternoon to the evening.

“Information given by an officer from the Mount Semeru Monitoring Post in Mount Sawur stated that food-induced ground vibrations were recorded on Monday from 11:39 am to 5.50 pm (West Indonesian Time, or WIB). The cold lava flows were quite intense in Besuk Lengkong in the Kobokan Curah Hamlet. So, the downstream residents were advised to stay alert and anticipate potential fooding,” said Joko Sambang, the Head of the Emergency Rehabilitation and Reconstruction Division at the Lumajang Regional Disaster Management Agency (BPBD).

High-intensity cold lava flow mixed with volcanic materials ran into a number of rivers, including Regoyo River, Jugosari River and Lanang River. Because of the accumulation and confluence of the currents, overflows occurred, blocking the inter-village roads in Supiturang Village and Pronojiwo Village. Jugosari Bridge, built by the locals, was also cut off, because it was made of wood and trunks of coconut trees.

Mount Semeru’s cold lava, a flow that hit four watersheds in Lumajang, also cut off the Tempursari route and isolated two sub-districts, Tempursari and Pasirian. The food containing volcanic materials from Mount Semeru overflowed into residential areas.

The Volcanological Survey of Indonesia has been taking measures, alerting people, warning and prohibiting the locals from doing anything near the river.

The intensity of the cold lava flow of Mount Semeru was still relatively high, and is predicted to continue until March 2022.

The locals are prohibited from working in the southeast sector along Besuk Kobokan, as far as 13 km from the crater (the center of the eruption). And they are asked not to stray closer than 500 meters from the river bank (riparian zone) along Besuk Kobokan, due to the potential of hot clouds and lava flows that can run up to 17 km from the mountain top.

The local community is urged to refrain from working within a 5-km radius from the crater/peak of Mount Semeru, because of the danger of extrusive igneous rocks, hot clouds, lava flows and mudflows along the river that begins at the peak of Mount Semeru. (eka)