For the more information about the geologic resources of the National Park Service, please visit http://www.nature.nps.gov/geology/.
What is a volcano and where are they found?
A volcano is an opening on the surface of the Earth through which magma (molten rock) and gas erupt. It is also the cone of erupted material that builds up around the surface opening.
Volcanoes are not randomly distributed over the Earth's surface. Volcanoes tend to form where tectonic plates collide or spread apart. More than half of the world's active volcanoes above sea level encircle the Pacific Ocean. Volcanoes can also grow in the middle of a tectonic plate, like the Hawaiian volcanoes.
Why does the National Park Service monitor volcanoes?
- The primary justification for volcanic monitoring is public safety and disaster reduction. Volcanic eruptions can obliterate landscapes and threaten lives, ecosystems, and property. Eruptions are typically preceded by weeks to months of restlessness, allowing eruptions to be forecast if volcanoes are properly monitored by experts.
- The U.S. Geological Survey (USGS) has the primary responsibility to monitor volcanic activity in the United States. The park service works closely with the USGS to monitor volcanic activity in and around the national parks.
- Monitoring Book
- Resource Facts
- Case Study
Geological Monitoring Book
Vital Signs Monitored
- Earthquake activity
- Ground deformation
- Gas emission at ground level
- Emission of gas plumes and ash clouds
- Hydrologic activity
- Slope instability
Volcano Monitoring (PDF - 1.24MB)
Of the more than 1,500 volcanoes worldwide believed to have been active in the past 1,000 years, 169 are in the United States and its territories. As of spring 2007, two of these volcanoes, Mount St. Helens in Washington and Kilauea, located within Hawai'i Volcanoes National Park, are erupting, while several others exhibit signs of restlessness.
Most volcanoes are capable of eruptions that pose significant threats to natural landscapes, lives, ecosystems, and property. Fortunately, eruptions are typically preceded by weeks to months of increasing restlessness, allowing eruptions to be forecast if volcanoes are properly instrumented and data are interpreted by teams of experts in the fields of geology, seismology, geodesy, and geochemistry of volcanoes.
NPS Volcanic Resource Facts
38 parks have volcanoes listed as a major feature.
21 NPS units contain active or recently active volcanoes and volcanic features.
Monitoring Volcanoes in the National Park Service
Case Study coming soon...
- Geologic Monitoring Book, Chapter 12 - Volcano Monitoring (PDF - 1.24MB)
- NPS Tour of Park Geology - Volcanoes
- Views of the National Parks - Monitoring Volcanoes
- Volcanic Hazards at Mount Rainier National Park
- U.S. Geological Survey - Volcano Hazards Program
- U.S. Geological Survey General Information Product 64 - Geologic Hazards at Volcanoes (PDF - 140KB)
Last Updated: April 16, 2012