Why is it important to monitor volcanoes?
The United States and its territories contain 169 geologically active volcanoes, of which 54 volcanoes are a very high or high threat to public safety [National Volcano Early Warning System (NVEWS)]. Many of these volcanoes have erupted in the recent past and will erupt again in the foreseeable future. As populations increase, areas near volcanoes are being developed and aviation routes are increasing. As a result, more people and property are at risk from volcanic activity. Future eruptions could affect hundreds of thousands of people. To help prevent loss of life and property, the U.S. Geological Survey and its partners monitor these volcanoes, and issue warnings of impending eruptions.
Real-time monitoring of volcanoes, with the use of volcano seismology, gas, and surface deformation measurements, permits scientists to anticipate with varying degrees of certainty, the style and timing of an eruption. While our present state of knowledge does not allow us to predict the exact time and place of eruptions, we can detect changes from usual behavior that precede impending eruptions. We communicate these changes in our volcano updates. The information in the volcano updates allows scientists, public officials, and people in communities at risk to make preparations that can reduce losses during an eruption. Because volcanoes can erupt with little warning, continuous monitoring is important even if a volcano is not showing signs of activity.