Largest known historical eruption in Africa: Dubbi volcano, Eritrea, 1861 Pierre Wiart1 and Clive Oppenheimer1 1 Department of Geography, University of Cambridge, Downing Place, Cambridge CB2 3EN, UK Dubbi volcano, located in the northeast part of the Afar triangle,erupted explosively in May 1861, showering maritime trafficin the Red Sea with pumice and plunging coastal settlementsinto darkness. Earthquakes associated with the opening phaseof the eruption were felt in Yemen, and explosions were heardas far as Massawa, 330 km distant. More than 100 local inhabitantswere reported killed, possibly as a result of pyroclastic flowemplacement. By October 1861, activity switched to basalticfire-fountaining focused along a 4-km-long summit fissure thatfed several lava flows that traveled as far as 22 km. We presenta reconstruction of this unusual explosive and effusive eruptionsequence based on interpretation of contemporary accounts, analysisof satellite imagery, field work, and laboratory geochemistry.The volume of lava flows alone, 3.5 km3, makes this the largestreported historical eruption in Africa. An anomalously coldNorthern Hemisphere summer in 1862, recorded in tree-ring records,could be the result of Dubbi's sulfate aerosol veil.