THE MOUNT BAKER VOLCANO: REVISITING THE 20-YEAR-OLD TRILATERATION NETWORK IN MOUNT BAKER WILDERNESS, WASHINGTON

Mount Baker, the northernmost stratovolcano of the Cascade Range in the United States, saw increased thermal output and activity from 1973 to 1975 and volcanologists anticipated an eruption. The volcano returned to pre-activity conditions at the end of 1975, but CO2 emissions have remained high, suggesting continued magma degassing. Between 1981 and 1983 the U.S. Geological Survey installed benchmarks using helicopter at 14 sites on Mt. Baker before the initiation of the 1984 Washington Wilderness Act prohibiting operation of mechanized equipment.

The purpose of this study is ultimately to: revisit the geodetic network for the first time since 1983; assess the condition of existing benchmarks; collect Global Positioning System (GPS) data at existing stable benchmarks; install new benchmarks for degraded or inaccessible sites; and compare 2004 trilateration data with the 1981-1983 survey to evaluate deformation of the volcanic edifice.

Activities for this field project comprise: visiting 6 of 14 original benchmarks; writing route descriptions to access the sites on foot and develop a photograph archive; make GPS observations and collect baseline data for future studies; report on changes found after data processing of the trilateration network from the northwest and southwest sections of the volcano.