Earth's Interior (IMAGE) Virginia Tech Caption Traditional thought holds that hot updrafts from the Earth's core cause volcanoes, but researchers say eruptions may stem from the asthenosphere, a layer closer to the surface. Credit Virginia Tech Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.