[1] Craig was involved in numerous research expeditions, which visited the Great Rift Valley of East Africa,[2] the crater of Loihi (now known as Kamaʻehuakanaloa), the Afar Depression of Ethiopia, Greenland's ice cores, and Yellowstone's geysers, among many others.
During World War I, John Craig (1868-1931) and his wife, actress Mary Young, led the first professional American stock theater company to travel to France and entertain troops at the front.
[10] Harmon Bushnell Craig died serving with an ambulatory corps run by the American Field Service, and was posthumously awarded the French Croix de Guerre.
Harmon Craig's mother, Virginia Stanley, was descended from Quakers who helped found schools for freed slaves.
Craig's study of the carbon isotope produced corrections that deal with mass fractionation and radiocarbon ages.
Craig's thesis work is considered a foundational accomplishment for its studies of 13 C and 12 C in a wide range of natural materials, including everything from ocean water to the atmosphere; volcanic gases; plants, coal, diamonds, and petroleum; sediments, igneous rocks and meteorites.
[5] His theory has been applied to applications as varied as determining food chains and the identifying the sources of stone for ancient statues.
[2] In 1953, Urey and Craig published results showing that chondrites, meteors from the Solar System, did not have a single fixed composition, as had been assumed.
[20] As a professor of geochemistry and oceanography at Scripps, Craig developed new methods in radiocarbon dating and applied radioisotope and isotope distribution to various topics in marine-, geo-, and cosmochemistry.
[22][23][21] In 1963, Craig received a Guggenheim Fellowship, using it to spend a year at the Istituto de Geologia Nucleare, Pisa, Italy.
[2] In 1971, as part of the Antipode Expedition, Craig and his colleagues gathered hydrographic casts and other data, and discovered a benthic front separating the South Pacific deep and bottom water.
[20]: 338 [1][34] During the 1970s Craig examined the relationship of gases such as radon and helium to earthquake prediction, developing a monitoring network at thermal springs and wells near major fault lines in southernmost California.
[38][39][40] Craig discovered submarine Hydrothermal vents by measuring helium 3 and radon emitted from seafloor spreading centers.
[42][43] Craig led 28 oceanographic expeditions and traveled to the East African Rift Valley, The Dead Sea, Tibet, Yunnan (China) and many other places to sample volcanic rocks and gases.
[1]: 10 Craig died at Thornton Hospital in La Jolla, California on 14 March 2003[2] from a massive heart attack[5] a day before his seventy-seventh birthday.
[53] Harmon's curiosity and sense of adventure knew no bounds... His drive for scientific achievement was unparalleled in my experience.