Effusive activity and ash to 7.3 km (24 000 feet) at Big Ben volcano, Heard Island, Indian Ocean
Satellite observations show that Heard Island’s Big Ben volcano remains active, with lava flows detected through late January and February 2026. The Darwin VAAC reported that the ash plume from a brief eruption around 14:00 UTC on February 11 reached 7.3 km (24 000 feet) above sea level and fully dissipated by the following day.
Satellite image of Heard Island, southern Indian Ocean on November 8, 2025. Credit: Copernicus EU/Sentinel-2, The Watchers
A short-lived eruption at Heard Island’s Big Ben volcano on February 11 produced an ash plume that rose to about 7.3 km (24 000 feet) and drifted eastward before dissipating by early February 12, according to the Darwin VAAC. Satellite imagery shows continued thermal anomalies and lava flows on several flanks, confirming the volcano remains in an active effusive phase.
By 06:40 UTC on February 12, the Darwin VAAC confirmed that the ash had completely dissipated, and no new emissions were observed. The advisory, numbered 2026/2, was subsequently terminated, with no ongoing eruptive activity reported.
The eruption occurred during a period of persistent thermal activity at the volcano. According to the Smithsonian Institution – Global Volcanism Program, satellite images captured between January 27 and February 1 showed temperature anomalies at the summit and along the western and south-western flanks, interpreted as active lava flows.
Additional anomalies on the north-eastern flank later in February were followed by darker cooling zones, consistent with recently emplaced lava.
Heard Island on the Kerguelen Plateau in the southern Indian Ocean consists primarily of the emergent portion of two volcanic structures. The large glacier-covered composite basaltic-to-trachytic cone of Big Ben comprises most of the island, and the smaller Mt. Dixon lies at the northwest tip of the island across a narrow isthmus. Little is known about the structure of Big Ben because of its extensive ice cover.
Eruptive activity at Big Ben is recurrent, typically involving effusive lava flows and intermittent ash emissions every few years. Its current eruptive phase (VEI 0) started in September 2012 after 4 years of quiescence.
This is one of the most remote volcanoes on Earth and lacks permanent monitoring instruments. Observations of its activity rely entirely on satellite data and occasional ship-based reports.
Several subglacial eruptions have also been reported at this isolated volcano, but observations are infrequent and additional activity may have occurred.
References:
1 Volcanic ash advisories for Heard volcano – Darwin VAAC – February 11 and 12, 2026
2 Heard volcano geological summary – GVP – Accessed February 12, 2026
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