What is the largest volcanic eruption in recorded history?

The largest volcanic eruption in recorded history was the 1815 eruption of Mount Tambora. The volcano, on Indonesia's Sumbawa Island, produced a colossal explosive event rated VEI 7, the second-highest level on the Volcanic Explosivity Index.

Activity intensified in April 1815, reaching its devastating climax on April 10. Pyroclastic flows raced down the slopes and destroyed settlements, while ash and pumice spread across the surrounding islands. The eruption removed roughly a third of Tambora's former height and left a caldera several kilometres wide.

The immediate disaster killed tens of thousands of people through explosions, ashfall, pyroclastic flows, tsunamis, disease, and famine. Later estimates place the total death toll at more than 70,000, though exact figures are uncertain because historical records were incomplete.

Sulfur-rich gases injected into the stratosphere reflected sunlight and disrupted global climate. The following year, 1816, became known as the “Year Without a Summer” after crop failures, cold weather, and unusual precipitation in parts of Europe and North America. Krakatoa was famous and highly destructive, but its 1883 eruption was substantially smaller than Tambora's.