Earliest references to California earthquakes are contained in the records of the Missions, and diaries of priests and soldiers stationed in Alta California by the Mexican or Spanish governments.
Earthquake records became far more accurate with the arrival of Thomas Tennant in San Francisco during the Gold Rush. He kept weather observations and noted local earthquakes. Later, the U.S. Weather Bureau took over that duty. In addition, newspapers here generally printed one-
Also invaluable for tracking earthquakes were various almanacs published in San Francisco and Oakland which kept
Almost all data for the post-1900 era, concerning dates and locations, come from scientific publications, such as Holdens catalogue of earthquakes, or records kept by Prof. Alexander McAdie of the Weather Bureau in San Francisco.
Information about the effects of those post-
There are also two reports that are invaluable for the researcher: Toppozada, et al, California Division of Mines and Geology (CDMG) Open File report 81-11 SAC on Pre-1900 California Earthquakes, and USGS Professional Paper 1527 by Stover and Coffman on the Seismicity of the United States 1568-1989.
Historical information has been added to the 1865, 1868, 1906, 1957 and 1989 earthquake sections to give the reader the sense of the vast effects of major earthquakes.