GROVE KARL GILBERT'S PHOTOGRAPHS AS EVIDENCE IN GEOLOGY: DOCUMENTING THE 1906 SAN FRANCISCO EARTHQUAKE

On April 18, 1906, Grove Karl Gilbert (1842-1918) of the United States Geological Survey (USGS) was in Berkeley, conducting experiments on stream transport and evaluating the damage of hydraulic mining in California. He began immediately to study the effects of the earthquake, taking over a hundred photographs of structures and landscapes disrupted by the tremors and conducting fieldwork, especially north of the Golden Gate in the Bolinas-Point Reyes area. Many of these images appeared in Gilbert's articles in USGS Bulletin 324 (1907), and in a massive report (1908-1910) edited by Andrew Lawson of the University of California, The California Earthquake of April 18, 1906: Report of the State Earthquake Investigation Commission. Collections of his photographs came to be archived at the California Academy of Sciences and at the USGS Photo Library in Denver.

Gilbert's use of photographs dated back to his work as an assistant to John Strong Newbery on the Ohio State Geological Survey in 1870. During his work (1871-1875) on the Wheeler Survey of the American West, Gilbert learned to take striking photographs from master photographer Timothy O'Sullivan (1840(?)-1882), who had apprenticed to the great Civil War photographer Matthew Brady (1823(?)-1896). Gilbert refined his photographic skill with John Hillers (1843-1925) of the Powell Survey during 1875-1879. Gilbert built up a large photographic library during his career with the USGS, documenting Niagara Falls, the Great Basin, Meteor Crater, the Sierra Nevada and the geology of Alaska (as geologist of the Harriman Expedition) in the years before 1906. After the earthquake, he continued to assemble photographs to illustrate his geological work. The publication of his images was influenced by the limitations of printing of the time; before 1890s, most of the published photographs were transferred to engravings for printing; thereafter, they began to appear as halftones and heliotypes.