Lengai, Ol Doinyo (Tanzania): Recorded Eruptions and Historical Activity

Ol Doinyo Lengai is a stratovolcano located in Tanzania within a rift zone tectonic setting on continental crust thicker than 25 kilometers. Standing at an elevation of 2,962 meters, the volcano has a documented historical record spanning multiple centuries, featuring 26 confirmed eruptions managed in the Smithsonian Global Volcanism Program records.

Eruption History and Chronology

The historical record for Ol Doinyo Lengai reaches back millennia, with the earliest recorded eruption starting around 1550 BCE, determined through tephrochronology correlation with a start year uncertainty of 1500 years. Confirmed eruptions span several centuries, including occurrences in the 16th century BCE, the 1st century BCE, the 7th century CE, the 14th century CE, the 19th century CE, the 20th century CE, and the 21st century CE.

Out of the 26 confirmed eruptions in the official record, 22 include Volcanic Explosivity Index (VEI) observations. The largest recorded VEI in the dataset is 3.0. Activity documented in the 20th and 21st centuries includes multiple events centered in the volcano's North Crater, utilizing reported observation methods.

Selected Historical Eruptions

Representative entries from the official eruption record illustrate the range of documented activity at Ol Doinyo Lengai:

• 1550 BCE: The earliest recorded eruption in the dataset, identified via tephrochronology correlation.
• July 2, 1904: A confirmed eruption originating in the North Crater based on reported observations.
• July 2, 1926: A confirmed North Crater eruption with a recorded VEI of 2.0.
• June 16, 2007 – October 9, 2010: A multi-year confirmed eruption in the North Crater featuring a recorded VEI of 3.0.
• April 9, 2017 – March 31, 2026: A confirmed eruption period in the North Crater with a recorded VEI of 0.0.