Dallas L. Peck, 76, an authority on volcanoes who served as director of the U.S. Geological Survey from 1981 to 1993, died Aug. 21 at Inova Fairfax Hospital. He had suffered complications from open-heart surgery in June.

Dr. Peck, a Reston resident, spent his entire career at the Geological Survey, starting in 1951. He worked in California and Hawaii before moving to the Washington area in 1966. He was chief of the geologic division from 1977 until he was appointed director of the survey, becoming the 11th in its history.

During his tenure, he expanded the scope of the survey's work on mineral resources, global change, water quality and mapping as well as risk assessments and management of earthquakes, landslides, land subsidence and volcanic eruptions. He also championed side-scan sonar imagery, used to map the sea floor.

After stepping down as director, he spent two years completing his long-term studies on the granites of Yosemite National Park and the Sierra Nevada mountain range, both in California. He also was an adviser to the Office of the Chief Geologist.

He worked in geologic research as an emeritus scientist until his death.

Dallas Lynn Peck was a native of Cheney, Wash., and received bachelor's and master's degrees in geology from the California Institute of Technology. He received a doctorate in geology from Harvard University in 1960.

He spent his early career studying the volcanoes and volcanic rocks of Hawaii and the western United States. In the mid-1960s, he helped train U.S. astronauts on what to expect on the lunar landscape. He also was among the first U.S. scientists to work with the Soviet Union and China in cooperative earthquake research in the 1970s.

His honors included the Interior Department's awards for meritorious and distinguished service as well as the Presidential Meritorious Executive Award.

A mountain range in Antarctica was named after him in 1989.

His memberships included the American Association for the Advancement of Science, the American Geophysical Union and the Cosmos Club.

He was a master gardener.

His first wife, Sue Lewis Peck, died in 1993.

Survivors include his wife, Shirley Smith Peck of Reston; three children from his first marriage, Ann McBride of Burbank, Calif., Stephen Peck of El Toro, Calif., and Army Maj. Gerritt Peck of Oak Hill, Va.; three stepchildren, Michael Benson of Reston, Donna Benson of Miami and Gayle Roberts of Chicago; a brother; four grandchildren; and a great-grandson.