Nightmare Without End

Study with participation from Heidelberg shows that supervolcanoes remain dangerous long after erupting. Besides cosmic impacts, supervolcanic eruptions rank among the worst catastrophes in the Earth's history, like that of the Toba volcano on Sumatra (Indonesia) approximately 75,000 years ago, which affected all of Southeast Asia and beyond. Eruptions of a similar magnitude are known worldwide only from Yellowstone (USA) and a few other volcanoes that were active within the current geological period of the Quaternary. Until now, scientists assumed that the biosphere recovered from the impact of such supereruptions in decades to centuries. Using the Toba volcano as an example, an international research team that includes Axel Schmitt from the Institute of Earth Sciences of Heidelberg University recently demonstrated that supervolcanoes remain active and dangerous for thousands of years after they erupt. Supervolcanic eruptions vent vast amounts of magma at the Earth's surface, cracking the Earth's crust above the evacuating magma chamber and leaving behind a depression known as a caldera that often fills with water. In the case of the Toba volcano, the caldera lake is about 100 km long, 30 km wide, and up to 500 m deep.