PORT TOWNSEND — Geologist Christina Heliker of Sequim will tell about her work at Mount St. Helens — which began shortly after its cataclysmic eruption May 18, 1980 — when she presents a lecture at 4 p.m. Saturday.
Heliker’s one-hour lecture will be at the First Baptist Church, 1202 Lawrence St., in uptown Port Townsend. It is sponsored by Jefferson Land Trust’s Geology Group (quimpergeology.org).
It is free and open to the public; donations of $5 are appreciated to defray expenses.
Following the big blast at Mount St. Helens, five smaller eruptions produced pyroclastic flows. Using traditional (pre-GPS) surveying techniques, Heliker was part of the “deformation crew” that measured inflation of the volcano’s flanks prior to each eruption as a means of predicting new activity.
By 1981, her fieldwork moved inside the crater. She measured changes to the lava dome before it erupted over the next several years.
During those trips, she collected samples of dome lava that contained inclusions of “foreign” rocks incorporated into magma as it rose through the crust. These samples became the focus of her graduate work.
According to Heliker, ash bursts from the dome, swarms of micro-earthquakes and constant rockfalls from the rim made crater fieldwork exhilarating.
More recently, she has revisited the crater, hiking to the toe of the fast-growing glacier wrapping around the dome.
Her presentation will include an update on current conditions at Mount St. Helens, nearly 40 years after the big eruption.
Heliker spent most of her career working for the U.S. Geological Survey (USGS) on active volcanoes. Her first job with USGS, however, was working on glaciers from an office in Tacoma.
When Mount St. Helens erupted in May 1980, Heliker quickly transferred to a Vancouver office that soon became the Cascades Volcano Observatory. She worked there for the next four years while completing a master’s degree at Western Washington University in Bellingham.
In 1984, she moved to USGS’s Hawaiian Volcano Observatory on the Big Island, where she monitored the 35-year eruption of Kilauea until her retirement.
Heliker returned to the Northwest in 2012, settling in Sequim, where she spends her time hiking and snowshoeing in the Olympic Mountains and working on photography.