scientists measured the intensity of small earthquakes in Yellowstone to scan the earth underneath it . They discovered a vast magma reservoir , a vast one scientists already knew about . Prehistoric eruptions of a volcano were some of earth 's largest earthquakes .
Scientist measured the thousands of small earthquakes in Yellowstone to scan the earth underneath it . They discovered a vast magma reservoir fueling a vast one scientists already knew about . Prehistoric eruptions of Yellowstone supervolcano were some of Earth 's largest explosions .