This long-term endeavor continues today. International air traffic corridors and active volcanoes in Alaska. One of the most vital roles of the USGS is to define and mitigate the risk of volcanic eruptions. Alaska has more than 40 active volcanoes that collectively have averaged two significant eruptions every year since 1945.
Volcanic ash is a severe threat to jet aircraft that fly over the North Pacific Ocean.
On an average of 4 days each year, explosive eruptions send potentially lethal clouds of ash directly into international air traffic routes over and near Alaska. Anchorage International Airport is the busiest air cargo hub in the United States. Rapid detection and notification of eruptions beneath Alaskan air routes are increasingly critical. USGS volcano seismologists servicing a seismic station south of Crater Peak, Mt. Spurr volcano. Earthquakes Alaska is the most earthquake-prone state in the Nation and one of the most seismically active regions in the world.