This is generally a slow process, but still very dangerous. Non-explosive eruptions bring on mud flows, landslides and volcanic ash hazard. The volcanic ash would probably go no further then 20 miles, beyond that point the danger would be minimal. Locating areas of possible hazard and evaluating them is the role of the U.S. Geological Survey. The scientists attempt to recognize signs of an impending eruption.
Geologists measure and record activity on the volcano.
Many events occur prior to an eruption that helps determine future eruptions, such as minor earthquakes and gas leakage. Recent minor eruptions from the Mount Shasta centers and vents give geologists basis to access the most likely kinds of future eruptive activity and potential hazards. Explosive and non-explosive eruptions have taken place at Mount Shasta and probably will occur in the future. These eruptions can and will cause severe damage and endanger people,property, wildlife and structures. Because Mount Shasta has many streams and rivers that drain into the Shasta River to the northwest, the Sacramento River to the west and southwest, and the McCloud River to the east, south, and southeast, the lava will flow a shorter distance than most volcanic flows.