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Monitoring Seismicity to Locate Earthquakes

Earthquake activity is the most consistent sign of volcanic unrest.

Seismic networks, used to detect and locate earthquakes, have been a mainstay of Cascade volcano monitoring networks since the 1970s. Seismicity at Cascade volcanoes is monitored in partnership between the Pacific Northwest Seismic Network (PNSN) and the CVO, as well as UNAVCO (through the Plate Boundary Observatory program). There is significant variability in the number of stations at each volcano, which reflects the degree of difficulty in operating seismic stations in remote locations, proximity to population centers, recency of eruptive activity, and land-use permitting restrictions.

Learn more about volcano seismicity: