A volcanic eruption is the point in which a volcano is active and releases its power , and the eruptions come in many forms . They range from daily small eruptions which occur in places like Kilauea in Hawaii , to megacolossal eruptions ( where the volcano expels at least 1,000 cubic kilometers of material ) from supervolcanoes like Lake Taupo ( 26,500 years ago ) and Yellowstone Caldera . According to the Toba catastrophe theory , 70 to 75 thousand years ago , a supervolcanic event at Lake Toba reduced the human population to 10,000 or even 1,000 breeding pairs , creating a bottleneck in human evolution . Some eruptions form pyroclastic flows , which are high-temperature clouds of ash and steam that can travel down mountainsides at speed exceeding an airliner
Toba catastrophe theory
Toba catastrophe theory
Natural hazard