# Anak Krakatau volcanic activity and new land formation > Live situation record from CLSTR: https://clstr.news/situations/20260922-anak-krakatau-volcanic-activity > Updated: 2026-09-24T05:20:08.000Z. Sources: 32. Developments: 3. The Anak Krakatau volcano in the Sunda Strait has undergone a shift in activity levels. In mid-September 2026, the volcano transitioned from a period of continuous eruption to a Strombolian phase, marked by more episodic activity. During this time, experts noted rapid constructive growth driven by a mature magma system, though officials indicated that the volcano’s current height and slope made tsunami-triggering collapses unlikely. By late September 2026, the Geological Agency downgraded the alert level from Level III (Alert) to Level II (Warning) following a downward trend in volcanic activity. This decision, effective September 21, 2026, was based on declining activity and deformation data showing deflation. Following the eruptions in early September, satellite imagery from the Geological Agency of Indonesia and Sentinel revealed the emergence of new land formations in the northwest, west, and southwest sectors. This expansion, totaling approximately 32.8 hectares, resulted from the deposition of lava flows and pyroclastic material during a 25-hour period of continuous eruption between September 4 and September 6, 2026. This growth has brought the volcano’s total land area to 341.5 hectares, exceeding its dimensions prior to the 2018 collapse. Researchers have also detected two small mounds or islets to the northwest and southeast of the main volcano. Experts clarify that these are accumulations of volcanic debris rather than independent volcanoes. The eruptions caused significant environmental impacts, with ash plumes reaching 15,000 feet and disrupting thousands of flights. Authorities continue to prohibit public access within a two-kilometer radius of the crater and advise maintaining a distance of at least 1 km from the newly detected mounds. Field surveys are scheduled for October 2026 to further investigate these new land masses. ## Claims - Two new small land masses or mounds were detected near the volcano in the northwest and southeast sectors. (corroborated by 6 sources) - Anak Krakatau's land area increased by approximately 32.8 hectares following eruptions in early September 2026. (corroborated by 5 sources) - The land expansion was caused by the accumulation of pyroclastic material and lava flows from continuous eruptions between September 4 and September 6, 2026. (corroborated by 4 sources) - Authorities have established a safety radius of 2km from the main crater and 1km from the new land masses. (corroborated by 3 sources) - Volcanic ash from the eruption disrupted thousands of flights. (corroborated by 2 sources) - Ash plumes reached altitudes of up to 15,000 feet (approximately 4,500 meters) or higher. (single source) - Field surveys are planned for October 2026 to confirm the nature of the new land formations. (single source) ## Timeline ### 2026-09-24: Anak Krakatau expands land area following September eruptions Anak Krakatau's land area has expanded by 32.8 hectares following eruptions in early September 2026, with two new small land masses detected near the volcano in the Sunda Strait. 23 sources. https://clstr.news/cluster/anak-krakatau-eruption-creates-new-land-in-sunda-strait ### 2026-09-22: Anak Krakatau volcano activity downgraded to Level II Warning Indonesia's Geological Agency has lowered Mount Anak Krakatau's activity level from Alert (Level III) to Warning (Level II) following a decrease in volcanic eruptions and seismic activity. 9 sources. https://clstr.news/cluster/anak-krakatau-volcano-alert-level-downgraded-to-level-ii ### 2026-09-15: Anak Krakatau transitions to Strombolian eruption phase Anak Krakatau has moved into a Strombolian eruption phase. Experts report rapid volcanic growth but note that current conditions pose a low tsunami risk from potential collapses. 5 sources. https://clstr.news/cluster/anak-krakatau-transitions-to-strombolian-eruption-phase --- Cite as: Anak Krakatau volcanic activity and new land formation. CLSTR, https://clstr.news/situations/20260922-anak-krakatau-volcanic-activity