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25 Dec 2023 | 01:59 PM UTC

Indonesia: Increased volcanic activity at Mount Semeru in East Java Province Dec. 25

Increased volcanic activity at Mount Semeru in East Java Province, Indonesia, Dec. 25. Exclusion zone in place.

Warning

Increased volcanic activity has been reported at Mount Semeru, located around 80 km (50 miles) south-southeast of Sidoarjo, East Java Province Dec. 25. Ash plumes have risen up to 1,000 meters (3,281 feet) from the crater, while hot clouds have been observed up to 3,000 meters (9843 feet) to the southeast of the volcano.

Authorities are maintaining a Level 3 (Standby) alert (the second-highest level on a four-tier scale) for Semeru. An exclusion zone of a 5 km (3 miles) radius from the crater remains in place. Authorities have advised residents to stop all activities in the southeastern sector of the volcano along the Besuk Kobokan River from the crater to 13 km (8 miles) away as well as within 500 meters (1,640 feet) of the Besuk Kobokan River from 13-17 km (8-10.5 miles) away from the crater. Residents should be vigilant for potential pyroclastic flows, lava flows, and landslides along rivers and valleys on the flanks of Mount Semeru, especially along the Besuk Kobokan and its tributaries, Besuk Bang, Besuk Kembar, and Besuk Sat.

Transportation disruptions are possible over the coming days. Authorities may impose ground travel restrictions along roads in affected areas, as ashfall could reduce visibility and make streets slippery. Localized traffic disruptions are possible.

Further significant eruptions could lead to airport closures or flight delays and cancellations at Malang's Abdul Rachman Saleh Airport (MLG); MLG is around 30 km (19 miles) northwest of the volcano. Indonesia's Volcano Observatory Notice for Aviation (VONA) maintains an orange warning, the second-highest of four levels, indicating that further eruptions could impact flight activity. VONA may issue new warnings in the coming hours or days due to the most recent eruption.

Health
Volcanic activity may impact air quality in areas of East Java Province surrounding Mount Semeru, especially Lumajang and Malang regencies. Following an explosive event, air quality could become a concern, particularly in areas near the crater. Individuals in the region - especially those with underlying pulmonary conditions such as asthma or chronic obstructive pulmonary disease (COPD) - may experience difficulty breathing and suffer from lower tolerance to physical exertion.

In the event of further eruptions, contact airlines for updated flight information; confirm flights before checking out of hotels or driving to the airport. Avoid areas with heavy ash accumulations. If operating in areas affected by the ash cloud, consider remaining indoors in air-conditioned facilities when possible. Those who must be outdoors should use facemasks and observe other precautions to avoid ash inhalation. Drive defensively; seek updated information on road conditions before driving or routing shipments through areas close to the volcano. Heed all official orders.