Deformation monitoring at Lassen Volcanic Center
When magma moves into a volcanic system, and closer to the surface of the earth, the area surrounding the volcano may move upward and outward. At Lassen Volcanic Center, this swelling is measured using the Global Positioning System (GPS).
Continuously recording GPS instruments are the most used type of volcanic deformation-monitoring equipment in the world. 24 satellites, orbiting the Earth twice each day, transmit their position in orbit to receivers on the surface of the Earth. The receivers record vertical and horizontal position, and by comparing these measurements through time, it is possible to determine the amount of movement for a specific location on the surface of the earth.
Between 2007 and 2008, eight GPS receivers were installed to make up the continuous monitoring network at Lassen Volcanic Center. Ground surveys show localized subsidence of the volcano, probably due to motion on regional faults.