2020 Penrose Medal

Presented to James Gregory Moore

James Gregory Moore

James Gregory Moore
US Geological Survey


Citation by Keith Howard

Jim Moore has forged whole new ways of understanding volcanoes, their deformation of oceanic lithosphere, and how batholiths grow. His insights have had far-reaching impact across a wide breadth of Earth science.

Jim’s long visionary career has mostly been at the U.S. Geological Survey in Menlo Park, within spitting distance of his birthplace in Palo Alto and his Stanford undergraduate degree. After attaining his M.S. at the University of Washington and Ph.D. at John’s Hopkins, he served in the Army before starting full time at the USGS Menlo Park campus. This has been his science home since 1956 except for a period as Scientist-in-Charge of the Hawaiian Volcano Observatory. With foresight, a lively curiosity, and spirit of adventure he has studied eruptions around the world; mapped a huge rugged swath across the Sierra Nevada; studied underwater geology via scuba, dredges, and 50 deep submersible dives; and used his careful observations to forge many new concepts.

Jim’s breakthrough that colossal submarine landslide deposits flank the Hawaiian chain, with proposed tsunami deposits washed to island heights of 380 m, brilliantly clarified that Earth’s volcanoes often fail catastrophically. His discovery that collapsing eruption columns drive devastating high-velocity base surges, like those at nuclear explosions, forever changed older views of dune-bedded volcaniclastic deposits. Jim’s creative work on submarine basalts inaugurated the study of volatiles in basaltic magmas, and he used volatiles to understand magma transport and submarine eruption. He showed how pillow lava, Earth’s most widespread volcanic landform, actually forms, grippingly filmed in Fire under the Sea.

Darwin and Dana proposed that ocean island volcanoes subside, but Jim first used tide gage data and ages of drowned coral reefs to measure Hawaiian subsidence rates, geologically constraining strength estimates of oceanic lithosphere. Jim recognized zonation of western North America’s batholiths, quantified as his 1950s’ Quartz Diorite Line, which he astutely interpreted as the western limit of continental igneous sources. Jim’s careful mapping first revealed the Sierra Nevada batholith’s two-stage construction separated by a major dike swarm, a succession now fundamental to models of Cordilleran tectonics.

Jim refined the geologic structures of Hawaiian volcanoes, tuyas (flat-topped subglacial volcanoes), and diatreme-like Surtsey volcano. Other landmark concepts include explanations of granite magma-chamber processes, the formation of orbicular granites, how accretionary lapilli form in eruption clouds, and more recently, pre-history anthropology and landform processes in the Sierra.

Beyond his continuing array of high-impact papers, Jim’s books Exploring the Highest Sierra and King of the 40th Parallel—Discovery in the American West artfully blend exploration, historical personalities, and science. His Photographic Atlas of Mid-Atlantic Ridge Rift Valley documents a different part of the planet. Recognizing Jim as “the quintessential field geologist,” Wes Hildreth expanded this way: “Jim Moore is the most imaginative, versatile, and seminal geologist of our time; and among the most fearless, innovative, enterprising, and productive. Jim’s 70-year career is a shining example of what Penrose specified to be recognized—eminent research in pure geology.” Stephen Sparks, another of those supporting Jim’s recognition, adds “He has produced many brilliant papers brimming with excellent observations and new insights on an astonishingly wide variety of subjects. Personally he is a delight to work with, unassuming and interested in understanding how volcanoes work.”

It is my great honor to congratulate Jim Moore as the Penrose Medalist for 2020.


Response by James Gregory Moore

Thankyou Keith for preparing the documents of nomination for the Penrose Medal in conjunction with Tom Sisson and for your kind citation. I am grateful also for those who wrote letters of support and to the Penrose Committee for their decision.

I have been doubly blessed in the pursuit of a geologic career. Firstly because of the remarkable places where I was posted by the U.S. Geological Survey and secondly because of the whole village of people who helped me. My beginning years were spent in studying and mapping in the high Sierra Nevada where glaciation has produced extraordinary exposures over large areas making it an ideal place to study plutonic processes.

I was next assigned to Hawaii where several ongoing volcanic eruptions of Kilauea illustrated geology in magnificent action. While at Hawaii I took on studies of the great bulk of the volcanoes submerged beneath the sea. Later I worked on volcanic activity in the Philippines, Japan, Iceland, Sicily, the Mid-Atlantic Ridge, Washington State, and British Columbia,. These opportunities of studying volcanos in unique places piqued my curiosity and opened many research prospects.

People are important. Three generations of scientists have inspired me. The older include professors Aaron Waters, George Thompson, Ernst Cloos, Francis Pettijohn, Peter Misch, Hoover Makin, and supervisors Paul Bateman, Robert Smith, and Don White. Four of these are Penrose medalists themselves.

A host of collaborators and coauthors of my generation include field geologists: Shigeo Aramaki, William Bryan, Renato Crisofolini, Michael Diggles, Frank Dodge, Edward Du Bray, Rishard Fiske, Catherine Hickson, Robin Holcomb, Clifford Hopson, Marie Jackson, Sveinn Jakobsson, David Jones, Winnie Kortemeirer, Peter Lipman, Jack Lockwood, William Melson, George Moore, Barry Moring, Kazuaki Nakamura, Warren Nokleberg, Dallas Peck, Don Peterson, Donald Richter, Jason Saleeby, Richard Schweickert, Thomas Sisson, Stephan Sparks, Paul Stone, Don Swanson, Robert Tilling, Don Thomas, and Richard Williams.

Also included are oceanographers: Robert Ballard, J.F. Campbell, William Chadwick, David Clague, Donald Fornari, Roger Hekinian, and William Normark; geophysists: Jerry Eaton, Robert Koyanagi, Harold Krivoy, Howard Oliver, Carl Rice; geochronologists: Andy Calvert, J.H. Chen, Brent Dalrymple, B.J. Szabo; geochemists Lewis Calk, Gerald Czamanski, Jacqueline Dixon, Bernard Evans, William Evans, Brent Fabbi, Jean-Guy Schilling, Thomas Wright; photographer: Lee Tepley; artist: Tau Alpha; computer specialist: R.K. Mark: and archaeologist: Mary Gorden.

The third generational group important in sharpening my outlook on the significance of our research are the students that include assistants in the field, in the lab, and aboard ship. Answering their questions sharpens one’s outlook on the significance of the research. Some of these students became close collaborators as they matured.

In addition, many others contributed to making this overall endeavor possible. They include transport providers including captains and crews of vessels, horse packers, and pilots of helicopters, airplanes, and submersibles. Other essential contributors are artists, computer specialists, photographers, draft persons, microprobe technicians, and analytical chemists.

I feel pride in accepting this award and acknowledging the help of a multitude of people from a village of supporters, and from my amazing wife, Karen. I am grateful to the U.S. Geological Survey for their support through my career and to the Geological Society of America for honoring me with the Penrose Medal.

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