# Wes Hildreth

Edward Wesley Hildreth III (known professionally as Wes Hildreth; born August 17, 1938) is an American geologist affiliated with the U.S. Geological Survey (USGS) and the California Volcano Observatory. Employed by the USGS since 1977 as a research geologist, Hildreth is a Department of the Interior senior scientist. Described in Wired as "one of the great volcanologists/petrologists of our time," his work in the fields of volcanology, petrology, and geologic mapping has been recognized with the Bowen Award [de] and Thorarinsson Medal, and with fellowship in the Geological Society of America (GSA) and the American Geophysical Union. Hildreth's body of research includes work on the volcanic history of the Cascade Range, magmatism of the Long Valley Caldera, and mapping of mountain regions in the Andes.

## Early life and education

Wes Hildreth, full name Edward Wesley Hildreth III, was born on August 17, 1938 in Newton, Massachusetts, and is of Scottish ancestry. His parents—a housewife from an upper class family and a middle class retail store manager—had married earlier that year. Wes grew up "bicoastal", and has lived most of his life in either Greater Boston or the San Francisco Bay Area; he attended schools in both California and Massachusetts, and graduated from Tamalpais High School as salutatorian in 1956. Hildreth ran the Dipsea Race in 1955, while a student at Tamalpais.
Hildreth attended Harvard College, where he majored in geology with a minor in government. While at Harvard, he was a cross country runner for the Harvard Crimson. He received a Detur Book Prize (awarded to sophomores with high academic standing) in 1958. Between his sophomore and junior years, he joined an army reserve unit and trained for six months at Fort Ord, earning the distinction "Outstanding Soldier of the Cycle" in 1959. In 1960, he placed 29th in the 1960 Boston Marathon, and was elected to Phi Beta Kappa. Hildreth graduated with a Bachelor of Arts degree cum laude in 1961. After graduating, he received a scholarship to travel the world, and he did for ten years, picking up a job as a naturalist for the National Park Service.
Hildreth started graduate school, but dropped out under the domestic pressure of the Vietnam War. He later returned to graduate studies: under the advisorship of Ian S. E. Carmichael, Charles M. Gilbert, and Herbert R. Shaw, Hildreth received a Doctor of Philosophy degree from the University of California, Berkeley in 1977, staying at Berkeley after graduation to complete postdoctoral work with Carmichael.

### Personal life

In 1964, Hildreth married a woman named Nancy (now Nancy Brown, married to Roger Brown). Wes and Nancy are separated, but appeared in an oral history interview together in 2016. Hildreth met Gail Mahood while a student at Berkeley, and they were married in 1982. The two are both geologists, and have published papers together.

## Career and research

Starting in 1966, 5 years after his bachelor's degree was completed, Hildreth worked as a naturalist for the National Park Service. That same year, he conducted research at Muir Woods National Monument, and published a report on the history of the area. During his time with the Park Service, he had stints visiting Death Valley and the Olympic Mountains. He left his position in 1970, later becoming an instructor at the University of California, Berkeley, where he worked from 1973 to 1975. In 1977, Hildreth received his Ph.D. from Berkeley; he joined the U.S. Geological Survey as a research geologist in the same year.
Hildreth's interest in the Panamint Ranges led him to return to Death Valley and the Bishop Tuff while studying at Berkeley. His analysis of the tuff was a major contribution to the field, and since that time he has published on a wide array of geoscience topics, including volcanology, petrology, and geologic mapping, with a focus on continental formations such as calderas. In the 1970s, Hildreth saw a start to his career by studying the Bishop Tuff and Long Valley Caldera, and also by collaborating with Bob Christiansen on research in Yellowstone National Park. His early research also helped solidify the scientific consensus that there is compositional zoning of magma reservoirs.
Prior to 1980, Hildreth's primary research partner was David A. Johnston, though he was killed by the 1980 eruption of Mount St. Helens. Since that summer, much of Hildreth's research has been conducted with Judy Fierstein, fellow USGS geologist. Their collaboration began in 1980, when Hildreth took Fierstein—then a fresh college graduate—to the Valley of Ten Thousand Smokes in Katmai National Park and Preserve to conduct field research. Hildreth had been studying the geology of Katmai since 1976, but this was Fierstein's first experience in the park. In 2012, Hildreth and Fierstein published a report to commemorate the centennial of the 1912 eruption of Novarupta. The pair have also published research on other volcanoes within the park, including Kaguyak Caldera. Their enduring partnership has proved fruitful, with them both becoming vital to each other's research. In 2019, the duo won the Florence Bascom Geologic Mapping Award, conferred by the Geological Society of America, for their mapping efforts in Alaska, Chile, and the western United States.
In 1979, Hildreth published the seminal paper on Bishop Tuff studies. Subsequent works by him have also helped establish a greater understanding of the Bishop Tuff and its origins. In the Andes, his work has made him a leading expert on the geology of Laguna del Maule. As of 2024, Hildreth is a staff member of the USGS California Volcano Observatory and works out of Menlo Park, California.

### Professional service

Hildreth has served as an associate editor of Andean Geology since 1987, a role he previously held at the Journal of Geophysical Research from 1984 to 1986. From 1991 to 2001, he also served on the editorial board of the Bulletin of Volcanology. Hildreth also participates in public events—he was a participant in the 2005 GSA field forum in the Sierra Nevada and the White–Inyo Mountains. He again participated in a GSA field forum in 2009, in Bishop, California, which was adapted into a special issue of Lithosphere. In July 2016, Hildreth and Fierstein hosted an interpretive lecture and hike at Devils Postpile National Monument.

### Awards and honors

At the May 1985 meeting of the Geological Society of America, Hildreth was elected a fellow of the society. In December of 1985, he was awarded the Norman L. Bowen Award [de] (named for Norman L. Bowen) of the American Geophysical Union for his geochemical and petrologic studies of the Bishop Tuff, Novarupta, and Yellowstone. Hildreth became a fellow of the union in January 1995. In 2004, Hildreth was awarded the Thorarinsson Medal (named for Sigurdur Thorarinsson) for his many contributions to volcanology, including eruptive and petrological studies at Mount Baker and Mount Adams in the Cascade Range, Mount Katmai in Alaska, and the Yellowstone Caldera; mapping of volcanic calderas in the Andes; and magmatic studies at Long Valley. The GSA awarded Hildreth and Fierstein the 2019 Florence Bascom Geologic Mapping Award (named for Florence Bascom) for their mapping efforts at Adams, Baker, Katmai, Laguna del Maule, and Long Valley as well as the Three Sisters, Simcoe Mountains, Pantelleria, Quizapu–Descabezado, and Mammoth Mountain.