User talk:CCLelouch

Signs of an Eruption The most common signs that a volcanologist looks is the seismic signature. As molten magma moves through rock, making its way to the surface, it causes small earthquakes. These are called harmonic tremors and are different from earthquakes created along fault lines. Another method is to study how the topography changes on the volcano. As magma rises beneath the volcano, it can cause the volcano to swell or rise. The large bulge that formed on Mt. St. Helens before it's 1980 eruption is a great example. Currently, the Three Sisters volcanoes in Oregon has risen in elevation, though it is unclear if this signals an eminent eruption. Source(s) http://vulcan.wr.usgs.gov/Glossary/Seism… http://www.learner.org/interactives/volc…