Questions About Super Volcanoes
What is a supervolcano?
The term "supervolcano" implies an eruption of magnitude 8 on the Volcano Explosivity Index, meaning that more than 1,000 cubic kilometers (240 cubic miles) of magma (partially molten rock) are erupted. The most recent such event on Earth occurred 74,000 years ago at the Toba Caldera in Sumatra, Indonesia.
What are some other examples of supervolcanoes?
Volcanoes that produced exceedingly voluminous pyroclastic eruptions and formed large calderas in the past 2 million years would include Yellowstone, Long Valley in eastern California, Toba in Indonesia, and Taupo in New Zealand. Other "supervolcanoes" would likely include the large caldera volcanoes of Japan, Indonesia, and South America.
I read that scientists couldn't find the Yellowstone caldera until they looked at a photo of Yellowstone from space. Is this true?
Not according to Bob Christiansen. Bob is the USGS scientist who delineated the three Yellowstone calderas and told the world about the great eruptions that formed them. Bob reports that he traced out the caldera boundaries through old fashioned field work... walking around with a hammer and hand lens and looking carefully at the rocks and their distributions. Most of the key observations were made in the 1960s and 1970s. Several authors have written that these large calderas were discovered from space and we suspect that the rumor probably got started because initial field work that delineated them was partly funded by NASA. The idea was to compare well-constrained geologic maps with images taken from space. So Bob's geologic map was used to verify the NASA images, not the other way around.
Also see our Supervolcano docudrama questions and answers page where scientists answer questions about Yellowstone Volcano and the new docudrama.
