Two new landmasses have emerged in the Sunda Strait near Mount Anak Krakatau following a continuous 25-hour eruption cycle, according to an evaluation by the Geological Agency of Indonesia’s Ministry of Energy and Mineral Resources released on Thursday, September 24, 2026. The newly formed features sit off the volcano’s northwest and southeast sectors, with state volcanologists attributing the land to extensive pyroclastic deposits and lava flows.
Geological Formation and Satellite Evidence
The appearance of the two new gumuk, or small island mounds, follows a period of heightened activity. SS Rita Susilawati, head of the Center for Volcanology and Geological Hazard Mitigation (PVMBG) under the Geological Agency, stated that the emergence correlates directly with nearly a full day of uninterrupted eruptions. Sentinel satellite imagery captured the morphological shifts, showing a massive addition of material in the northwest-to-southwest sector of the volcano.
Preliminary analysis from the agency indicates that fluid magma reached the surface through an elongated fissure stretching from the northwest to the southeast. This directional venting forced volcanic debris into distinct shallow-water deposits that eventually broke the surface of the Sunda Strait. Alongside these two isolated mounds, the agency calculated a separate new land expansion covering 32.8 hectares nestled between Anak Krakatau and Sertung Island—a landmass nearly the size of the Prambanan Temple complex.
Despite the dramatic visual changes captured from space, Indonesian disaster officials emphasize that these formations are not standalone volcanoes. Daryono Perwira Sakti, a member of the Indonesian Disaster Management Experts Association, clarified in an official statement that the landmasses consist entirely of accumulated volcanic materials—including ash, rock, and cooled lava—piled onto the shallow seafloor of the 1883 caldera remnants.
“Whether this landmass expands or vanishes depends entirely on the battle between volcanic activity and natural erosion,” Daryono noted, explaining that ongoing eruptions could cement the deposits into permanent rock, while wave action and marine abrasion risk washing away unconsolidated sand if activity ceases.
Current Volcanic Status and Public Safety Restrictions
Mount Anak Krakatau remains at Level III (Siaga, or Standby), a designation reinforced by continuous monitoring from the Kalianda post in Lampung and the Pasauran post in Banten. The volcano’s baseline hazard zone restricts entry within a 2-kilometer radius of the active crater. In response to the newly surfaced island mounds, the Geological Agency has issued an additional restriction, urging residents, fishermen, and maritime operators to stay at least 1 kilometer away from the two specific maritime mounds for safety.
The latest formation follows a sequence of energetic phases in the region, including short-duration Strombolian explosions and regional ash dispersion monitored by disaster mitigation agencies across Lampung and Banten. While main commercial ferry routes operating between Merak and Bakauheni continue to function normally outside danger zones, authorities maintain heightened vigilance across coastal communities in the Sunda Strait.