Two New Islands Emerge Near Indonesia’s Anak Krakatau After September volcano eruption today

Two new islands have formed in the waters around Indonesia’s Mount Anak Krakatau following a major 25-hour eruption in September that grounded flights and stranded more than 300,000 passengers. The volcano eruption today continues to draw attention as monitoring agencies assess ongoing activity around the site.

New Islands Formed by Anak Krakatau Eruption

The new islands were identified in Sentinel satellite imagery, one located 760 meters northwest and the other 495 meters southwest of Anak Krakatau. [1] The islands were spotted in satellite images of the water-filled caldera in which Anak Krakatau stands, according to Rita Susilawati of the PVMBG Centre for Volcanology and Geological Hazard Mitigation. [1] “Based on an evaluation of Sentinel satellite imagery, two formations resembling small islands can be seen around Mount Anak Krakatau” in the Sunda Strait between the islands of Java and Sumatra, she added. [1] Sentinel is a fleet of Earth observation spacecraft developed by the European Space Agency. [1] One of the islands was located about 760 meters northwest of Mount Anak Krakatau, the other about 495 meters southwest. [1]

Uncertain Longevity of the New Landmasses

It remains unclear whether the formations are emerging from the caldera base like Anak Krakatau itself or are deposits of volcanic material that may erode over time. [1] Rita said it was too early to refer to the islands as “children” of Mount Anak Krakatau — which itself was formed by an underwater eruption in the caldera or depression left behind after the massive 1883 blowout of the original Krakatau volcano. [1] “Anak” means child in Bahasa Indonesia. [1] Rita said further research was needed to determine if the new islands were emerging from the base of the caldera in a similar way than Anak Krakatau did, or whether they were formed by deposits of volcanic material. [1] In the case of Anak Krakatau, several landmasses briefly emerged starting in 1927 and then disappeared due to erosion before an enduring island formed in 1930, she added. [1] The two new islands may similarly be eroded away over time. [1]

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September volcano eruption today Impact and Current Alert Status

Mount Anak Krakatau erupted for 25 hours nonstop in September, blanketing cities in volcanic ash and prompting multiple airports to close. [1] More than 300,000 passengers were left stranded. [1] Rita said Anak Krakatau was at alert Level 2, the second lowest out of four danger categories. [1] People are advised not to approach within 3 km of the eruption center. [1] Anak Krakatau is currently at alert Level 2, with a 3 km exclusion zone in place. [1]

Separate Eruption at Gunung Marapi

Gunung Marapi in West Sumatra erupted on 1 October 2026, marking its 63rd eruption of the year, with ash drifting south toward Padang Panjang and Tanah Datar. [2] The eruption was recorded on a seismograph even though the ash column was not observed visually due to cloud cover over the summit. [2] The seismic record showed eruption activity with a maximum amplitude of 19.5 millimeters and a duration of about 27 seconds. [2] The ash distribution was observed heading south from Gunung Marapi toward the areas of Padang Panjang City and Tanah Datar Regency. [2] Gunung Marapi remains at Level II (Waspada). [2] The public, climbers, visitors, and tourists are prohibited from entering or conducting activities within a three-kilometer radius of Kawah Verbeek, the eruption center. [2] Residents and tourists are asked to continue to pay attention to applicable safety provisions in the Gunung Marapi area and avoid areas around the center of volcanic activity. [2] People living near valleys, flow paths, and riverbanks originating from the peak of Gunung Marapi are urged to increase vigilance against potential lahars, especially during rain in the peak area. [2] The public is advised to wear masks to protect the nose and mouth from volcanic ash exposure that can trigger respiratory problems, and to use eye and skin protection if ash rain occurs. [2] Residents should also secure clean water supplies and clean up volcanic ash piled on house roofs to reduce the risk of building damage. [2] The public is urged not to spread unverified information and to follow official information and directions from the local government. [2]

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Missing Journalists and Crew

Five journalists and three boat crew members remain presumed dead after disappearing while covering the September Anak Krakatau eruption. [1] Five journalists on a mission to cover the September eruption were declared presumed dead, along with three boat crewmembers, nearly two weeks after the vessel they were traveling in disappeared without a trace. [1]

Geological Context

Indonesia lies on the Ring of Fire, accounting for high volcanic and seismic activity. [1] Indonesia sits on the Ring of Fire, where the meeting of continental plates causes high volcanic and seismic activity. [1]

What to watch next: Further research is needed to determine if the new islands were emerging from the base of the caldera or formed by deposits of volcanic material, while Gunung Marapi remains at Level II with a three-kilometer exclusion zone and residents are advised to stay alert for lahars and ash.

Further Reading

• Live Volcano Activity