This eruption was the last and largest of four eruptions of Toba during the Quaternary epoch. It had an estimated Volcanic Explosivity Index of 8 (described as "apocalyptic"). It made a sizable contribution to the 100x30 km caldera complex. The mass it threw out was 100 times greater than the largest volcanic eruption in recent history. That was the 1815 eruption of Mount Tambora in Indonesia, which caused the 1816 "Year Without a Summer" in the northern hemisphere.