Should U.S. be worried about Earthquakes and volcanoes?

Yellowstone is capable of eruptions thousands of times more violent than the Mount St. Helens eruptions in 1980. The northern Rockies would be buried in many feet of ash, which would rain on almost everyone in the United States. There are seven volcanic regions in California with zones of molten rock beneath the surface.

California has a lot of earthquakes. However, the most significant earthquakes in the country are not in California. A much greater hazard exists north of the San Andreas fault where the ocean crust is being forced beneath the North American continent. There are three active volcanoes in California. These are Mammoth Lakes, Lassen, and Shasta.