Porter Gunung Semeru, Ranu Kumbolo via Ranu Pane 

As of August 6, 2025, Mount Semeru in Indonesia has erupted again. Volcanic ash was reported to have reached approximately 700 meters (2,300 feet) above its peak in Lumajang Regency, East Java.

Mount Semeru has a history of frequent activity. It has been in a state of near-constant eruption from 1967 to the present, with historical eruptions typically having a Volcanic Explosivity Index (VEI) of 2 or 3.

Notable recent eruptions include:

• December 4, 2022: This eruption led to the raising of the alert status to the highest level. Hot avalanches of lava slid down the volcano's side, and nearly 2,000 people were evacuated. Pyroclastic flows extended significantly, and the alert level called for awareness of hot clouds, lava flow, and lahar flow.

• December 4, 2021: This was a significant eruption where ash emissions reached high altitudes, and pyroclastic flows approached populated areas. This event resulted in fatalities, injuries, and displacement of over 10,000 people, with significant damage to housing and infrastructure. The eruption was partly attributed to heavy rainfall causing the collapse of the lava dome.

The volcano's activity often involves ash plumes, pyroclastic flows, and debris avalanches. Residents are generally advised to stay within a certain radius of the crater, and specific areas are designated as dangerous due to potential hazards like hot clouds and lava flows.