JAKARTA – Mount Semeru, a highly active volcano in East Java province, Indonesia, erupted again Tuesday, sending a towering column of ash and hot gas into the sky. The eruption, which began at 5:30 p.m. local time, produced an ash plume reaching approximately 2,000 meters (6,562 feet) above the summit, drifting northeast and east, according to the Center for Volcanology and Geological Hazard Mitigation.
The eruption follows a period of increased unrest at Mount Semeru, with multiple eruptions recorded on Monday, signaling continued volcanic activity. Authorities have maintained a Level III alert for the volcano, the second-highest level in Indonesia’s four-tier warning system, indicating a potential for further eruptions. This alert level signifies that the volcano is exhibiting signs of increased activity and warrants heightened vigilance.
Seismographs registered the eruption lasting over seven minutes, indicating a sustained release of energy. While no immediate casualties or significant damage have been reported, the Center for Volcanology and Geological Hazard Mitigation has warned of the potential for lahars – volcanic mudflows – should heavy rainfall occur. The accumulation of volcanic material on the slopes of the mountain creates a hazardous condition, particularly during periods of precipitation.
Mount Semeru is one of Indonesia’s approximately 130 active volcanoes. The country is situated on the Pacific Ring of Fire, a region known for its frequent seismic and volcanic activity. The Ring of Fire is a horseshoe-shaped area around the edges of the Pacific Ocean where numerous tectonic plates interact, leading to earthquakes and volcanic eruptions. For Indonesia, this geography underpins not only recurring natural disasters but also long-standing disaster-management policies and funding priorities at both national and local levels.
Indonesia’s Center for Volcanology and Geological Hazard Mitigation is the government agency responsible for monitoring volcanic activity and issuing warnings to the public. The agency utilizes a network of seismographs, visual observations, and other monitoring tools to assess the state of volcanoes across the archipelago. The four-tier alert system is designed to provide a clear and consistent framework for communicating volcanic risk to communities and authorities. Level I indicates normal activity, Level II signifies increased activity, Level III represents an alert status, and Level IV signifies a critical situation with imminent eruption. These technical alerts feed directly into evacuation planning and emergency budgeting under the country’s national disaster law, implemented through the National Agency for Disaster Management and related regulations that define when local governments can mobilize extraordinary resources in response to volcanic threats. For readers seeking the formal framework, the government’s disaster risk governance is anchored in Indonesia’s national disaster management legislation and associated regulations as summarized on the official portal of the National Agency for Disaster Management.
The potential for lahars poses a significant threat to communities living near Mount Semeru. These destructive mudflows are formed when volcanic ash and debris mix with water, creating a slurry that can rapidly flow down river valleys, burying everything in its path. Authorities are closely monitoring rainfall patterns and river levels to provide timely warnings to residents in vulnerable areas. In recent years, repeated eruptions at Semeru have prompted the designation of permanent danger zones on the volcano’s slopes and periodic reviews of land-use and resettlement plans, as local officials weigh the economic pull of fertile volcanic soils against mounting safety concerns. For a broader sense of Mount Semeru’s recent activity trends, including earlier eruptions that sent ash several kilometers into the sky, see historical activity summaries maintained by specialist observatories such as VolcanoDiscovery.
The Center for Volcanology and Geological Hazard Mitigation continues to monitor Mount Semeru’s activity and will provide further updates as the situation evolves. Residents are advised to heed all official warnings and evacuation orders, as local administrations coordinate school closures, transportation diversions, and potential evacuations in line with national disaster-response protocols.