Thermal Anomaly at Ol Doinyo Lengai Suggests Lava Overflow
Tanzania’s Ol Doinyo Lengai, the world’s only active volcano erupting sodium-carbonatite lava, is showing signs of increased activity. A Sentinel satellite captured a significant thermal anomaly on May 27 that filled the entire summit crater—an unusual event for a volcano whose lava, at just 500–600°C, is too cool to glow visibly during the day.
Normally, small infrared hotspots hint at active hornitos—small lava vents—but the scale of this anomaly suggests a lava overflow, possibly triggered by the collapse of a hornito and the release of a lava pond across the crater floor.
Increased thermal signals have persisted in subsequent satellite imagery. These observations align with earlier geophysical data collected by an international team led by Sarah Stamps and Ntambila Daud of Virginia Tech. Since 2016, six GNSS stations installed around the volcano have monitored subtle ground deformation. Between March and December 2022, researchers detected rapid uplift, followed by steady elevation through August 2023. No deformation was recorded before or after, and modeling suggests the activity was caused by a shallow magmatic intrusion—potentially marking a phase of volcanic heating.
Despite these signs, on-site observations remain rare. Post-pandemic cost hikes have sharply reduced expeditions to the remote Rift Valley region. Even fewer eyewitness reports come from Nyamuragira volcano in the Democratic Republic of Congo, where insecurity and conflict near Goma further hinder access. Nyamuragira remains far more active than Lengai, emitting thermal energy levels over 1,980 megawatts—compared to just single-digit values at Ol Doinyo Lengai.