What is the name of and location of the volcano?
As of November 20, 2025, Mount Semeru, has erupted 10 times on Java Island, Indonesia (1). The eruption has forced evacuations and briefly raised concerns over at least 178 mountain climbers, guides, porters, and tourist officials in the area, all of whom have been safely evacuated (2).
Also known as Mahameru, Mount Semeru is the highest peak on Java, standing at 3,676 meters (12,060 feet) above sea level. Mount Semeru rises high within the Bromo-Tengger-Semeru National Park in Lumajang Regency, East Java Province. The volcano is also part of the Pacific Ring of Fire, a seismically active region known for frequent earthquakes and volcanic eruptions.
Which cities or areas are affected by the volcanic eruptions?
The volcanic eruptions are directly impacting Lumajang Regency (specifically Supiturang village) and villages along the Besuk Kobokan River.
Poor air quality from smoke and vog, a hazy mixture of SO2 gas and aerosols, has also affected several cities in the region, including:
Poor air quality in East Java, Indonesia. Source: IQAir.
What is the current status of the volcanic event?
Authorities have raised the alert level to its highest due to ongoing eruptions. The danger zone has been extended to 8 kilometers (5 miles) from the crater and along the path of the Besuk Kobokan River, where pyroclastic flows and lava are directed.
As of November 20, the volcano is still highly active, with eruptions emitting ash, lava, and hot gas. Monitoring and mitigation efforts are ongoing to manage risks and protect nearby communities.
Are there any evacuation orders or alerts in place?
Authorities have issued mandatory evacuation orders for residents within the 8-kilometer (5-mile) danger zone around Mount Semeru (3). The alert level remains at its highest.
Over 1,000 people, including residents and climbers, have been evacuated to temporary shelters such as schools, mosques, and government buildings.
How can I protect myself from volcanic smoke?
Always plan ahead to protect yourself from a volcanic eruption.
- Get a free air quality app for real-time air quality alerts and forecasts.
- Shut doors and windows and set the HVAC to recirculate mode.
- Run a high-performance air purifier to filter volcanic smoke.
- Contribute to your community’s outdoor air quality data.
- Stay indoors; if you do need to go outdoors, wear a KN95/FFP2 mask.
