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ENGEO <br /> INCORPORATED <br /> <br /> <br />5150.100.101 <br />March 31, 2008 7 <br />CONCLUSIONS AND RECOMMENDATIONS <br /> <br />The site is located within a State of California Earthquake Fault Zone (1982). As discussed above, <br />the main trace of the Calaveras fault has been located near Foothill Road and no indications of <br />faulting were encountered in exploratory trenches on the west side of the main trace. To reduce the <br />potential for adverse impacts to the planned building from fault rupture, recommendations for <br />setbacks are provided below. <br /> <br />We recommend that all structures intended for human occupancy be setback at least 50 feet from the <br />fault features encountered in the Geotechnical Engineering Inc. Trench 1. This setback zone is <br />depicted on Figure 2. <br /> <br />Given the previous fault mapping by Hart (1991) and Crane (1988) and the geomorphic features in <br />the vicinity, it is possible that a fault may exist to the southwest of the trenching that has been <br />completed at the site. To account for the possibility that a fault may exist under the existing <br />driveway or to the southwest of the existing driveway, we recommend that all structures intended for <br />human occupancy be setback at least 25 feet northeast of the existing driveway. <br /> <br />As shown on Figure 2, the currently planned building location appears to be in conformance with the <br />setback recommendations provided in this report. Based on the findings of this report, the potential <br />for fault rupture in the area of the currently proposed structure appears to be low. We should be <br />given the opportunity to review any changes to the building layout. In addition, we recommend that <br />the fault set-back lines be clearly identified on the grading and improvement plans. <br /> <br />During a major seismic event that causes ground rupture on a primary fault zone such as the <br />Calaveras fault zone, secondary ground deformations can occur in the region adjacent to the primary <br />fault zone. The extent and magnitude of this zone of secondary deformation are difficult to estimate <br />but most secondary deformations have been observed to take place on shear zones or other faults that