The system erupted violently over an eight - month period between June 1783 and February 1784 from the Laki fissure and the adjoining volcano Grímsvötn, pouring out an estimated 42 billion tons 14 km (3.4 cu mi) of basalt lava and clouds of poisonous hydrofluoric acid and sulfur dioxide compounds that contaminated the soil, leading to the death of over 50 % of Iceland 's livestock population, and the destruction of the vast majority of all crops. This led to a famine which then killed approximately 25 % of the island 's human population. The lava flows also destroyed 20 villages.
when was the volcanic eruption that killed a quarter of the population of iceland
an eight - month period between June 1783 and February 1784