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SAN LEANDRO SHORELINE DEVELOPMENT DRAFT EIR <br />CITY OF SAN LEANDRO <br />GEOLOGY, SOILS, AND SEISMICITY <br />TABLE 4.5-2 APPROXIMATE ACTIVE FAULT DISTANCES AND DIRECTIONS <br />Active Fault <br />Approximate <br />Distance from <br />Project Site <br />(Miles) <br />Approximate <br />Direction from <br />Project Site <br />Hayward <br />3.8 <br />Northeast <br />Calaveras <br />12.0 <br />Northeast <br />San Andreas <br />14.5 <br />Southwest <br />Concord -Green Valley <br />19.0 <br />North -Northeast <br />San Gregorio <br />22.0 <br />Southwest <br />Rodgers Creek <br />30.0 <br />North -Northwest <br />Source: Allan Kropp & Associates, 2014 <br />Several large earthquakes have occurred throughout the region during historic times. These included <br />several earthquakes on the Hayward fault as well as earthquakes on the San Andreas and Calaveras faults. <br />Commonly, historic earthquakes are characterized in terms of Local Magnitude (ML), which has also come <br />to be known as Richter Magnitude (M). A brief summary of information on historic earthquakes in the <br />area is given below. <br />Three earthquakes larger than M 6.0 are thought to have occurred on the Hayward fault during historical <br />time.10 On October 21, 1868, an earthquake of approximately M 6.8 occurred on the southern segment of <br />the Hayward fault. This earthquake reportedly produced surface ground rupture from Oakland to the <br />Warm Springs district of Fremont, a length of approximately 30 miles. The other two earthquakes <br />occurred in 1858 (M 6.1) and 1911 (M 6.6). Both of these earthquakes were also centered in the southern <br />portion of the Hayward fault." <br />The largest historical earthquake in the Bay Area occurred on the San Andreas fault near San Francisco in <br />1906. That earthquake, of M 8.3, caused widespread damage throughout the region. More recent <br />earthquakes in the region include the October 17, 1989, Loma Prieta earthquake on the San Andreas fault <br />(M 7.1); the Hollister, Coyote Lake, and Morgan Hill earthquakes of 1974, 1979, and 1984, on the <br />Calaveras fault, (M 5.2, M 5.9, and M 6.2, respectively); the 1957 Daly City earthquake on the San Andreas <br />fault (M 5.3); two Santa Rosa earthquakes of 1969 on the Rodgers Creek fault (M 5.6 and M 5.7); and the <br />South Napa earthquake in August 2014 (M 6.0). <br />10 Toppozada, Tousson R., and David L. Parke, 1982. Area Damaged by the 1868 Hayward Earthquake and Recurrence of <br />Damaging Earthquakes near Hayward, California Department of Conservation, Division of Mines and Geology Special Publication <br />62. <br />11 Toppozada, Tousson R., Charles R. Real, and David L. Parke, 1981. Preparation of Isoseismal Maps and Summaries of <br />Reported Effects for Pre -1900 California Earthquakes: California Department of Conservation, Division of Mines and Geology <br />Open -File Report 81-11. <br />4.5-8 DECEMBER 2014 <br />