Immediately after the San Francisco earthquake and fire of April 18,1906, it was decided to arrange for an investigation of their effects on buildings and materials of construction. According!}', on April 19 Richard L. Humphrey was sent to San Francisco for this purpose, as secretary of the National Advisory Board on Fuels and Structural Materials and representing the structural materials division of the United States Geological Survey. At the request of the President, Capt. John Stephen Sewell, Corps of Engineers, United States Army, was sent to San Francisco on a similar errand by the War Department under order of April 23, 1906. Frank Soule, dean of the college of civil engineering of the University of California, was asked late in the fall of 1906 to prepare a report on the general earthquake and fire conditions. G. K. Gilbert, of the United States Geological Survey, also a member of the California earthquake investigation commission, who was near San Francisco at the time of the disaster, was asked to prepare a brief special report on the phenomena of the earthquake.
The investigations of these three engineers were conducted independently, and their reports have been prepared without collaboration. Under these circumstances there are necessarily some differences of opinion as to matters of detail, but as to the more important features the writers are in hearty accord. About four hundred illustrations were submitted with the original reports; many of these do not appear with the printed reports because their use would have involved duplication, but wherever a view given by one author was rejected because of its similarity to a view by another author showing the same engineering features, a reference to the accepted view has been inserted. The legend appended to each illustration indicates whether the original view was actually taken by the author or was procured from another source.
US Department of the Interior, "The San Francisco Earthquake and Fire April 18, 1906 and Their Effects on Structures and Structural Materials" (1907). Federal Documents. 16.