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Lutzky Associates Development. LP - Geotechnical Investigation <br />MACTEC Project 4953-03-2631 <br />September 18.2003 <br />Seismicity <br />Earthquake Catalog Data <br />The seismicity of the region surrounding the site was determined from research of an electronic <br />database of seismic data (Southern California Seismographic Network, 2003). This database <br />includes earthquake data compiled by the Cali fornia Institute of Technology from 1932 through <br />2002 and data for 1812 to 1931 compiled by Richter and the U.S. National Oceanic Atmospheric <br />Administration (NOAA). The search for earthquakes that occurred within 100 kilometers of the <br />site indicates that 394 earthquakes of Richter magnitude 4.0 and greater occurred from 1932 <br />through 2002; 4 earthquakes of magnitude 6.0 or greater occurred between 1906 and 1931; and <br />one earthquake of magnitude 7.0 or greater occurred between 1812 and 1905. A list of these <br />earthquakes is presented as Table 3. Epicenters of moderate and major earthquakes (greater than <br />magnitude 6.0) are shown in Figure 5. <br />The information for each earthquake includes date and time in Greenwich Civil Time (GCT), <br />location of the epicenter in latitude and longitude, quality of epicentral determination (Q), depth in <br />kilometers, distance from the site in kilometers, and magnitude. Where a depth of 0.0 is given, the <br />solution was based on an assumed 16-kilometer focal depth. The explanation of the letter code for the <br />quality factor of the data is presented on the first page of the table. <br />Historic Earthquakes <br />A number of earthquakes of moderate to major magnitude have occurred in the Southern <br />California area within the last 70 years. A partial list of these earthquakes is included in the <br />following table. <br />11