Wes Hildreth

Edward Wesley Hildreth III (August 17, 1938 – June 19, 2025) was an American geologist affiliated with the U.S. Geological Survey (USGS) and its California Volcano Observatory. Employed by the USGS as a research geologist from 1977 until his death, Hildreth was 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 geological mapping had been recognized with the and Thorarinsson Medal, and with fellowship in the Geological Society of America (GSA) and the American Geophysical Union. Hildreth's body of research included 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 was of Scottish ancestry. His parents—Marion Frederica “Freddie” MacVicar, a housewife from an upper class family, and George Edward Hildreth, a middle class retail store manager—had married earlier that year. Wes was their firstborn, followed by his siblings Deborah and Bruce. Wes grew up "bicoastal", and 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 in 1956 as the salutatorian of Tamalpais High School in Mill Valley, California. Hildreth ran the Dipsea Race in 1955, while a student at Tamalpais.

Hildreth attended Harvard College, the undergraduate school of liberal arts and sciences at Harvard University, 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,

Hildreth started graduate school in 1970, but dropped out under the domestic pressure of the Vietnam War. During his time with the Park Service, he worked at Death Valley National Park, Olympic National Park, Grand Canyon National Park, and Glacier Bay National Park and Preserve. His early research also helped solidify the scientific consensus that there is compositional zoning of magma reservoirs. In 2012, Hildreth and Fierstein published a report to commemorate the centennial of the 1912 eruption of Novarupta. The pair had also published research on other volcanoes within the park, including Kaguyak Caldera. Their enduring partnership proved fruitful, with them both becoming vital to each other's research. Subsequent works by him helped establish a greater understanding of the Bishop Tuff and its origins. In the Andes, his work made him a leading expert on the geology of Laguna del Maule. At the time of his death in 2025, Hildreth was a staff member of the USGS California Volcano Observatory and worked out of Menlo Park, California. 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 1985, he was awarded the (named for Norman L. Bowen) of the American Geophysical Union for his geochemical and petrologic studies of the Bishop Tuff, Novarupta, and Yellowstone.

On June 19, 2025, around 11:50 a.m., Hildreth was killed in a crash while traveling on State Route 360 in Nevada. He was the passenger in a Chevrolet Tahoe that was struck while turning left by a semi-truck attempting to overtake. Hildreth was declared dead on the scene, at the age of 86. An unnamed driver was hospitalized. Earlier that month, Hildreth had been inducted into the Dipsea Race Hall of Fame.

The California Volcano Observatory published a memorial to Hildreth on July 8, 2025. It was reposted the same day by the Dipsea Race organization on Facebook.