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MOUNTAIN HOUSE PROPOSED ALTAMONT HEIGFITS TENTATIVE MAP 4_ ENVIRONMENTAL CHECKLIST 4.6 GEOLOGY AND SOILS are know to exist near the project site (Kleinfeldor USA,2006). No active.faults have been identified within the Mountain House Community(CDMG, 2000). Therefore, surface fault rupture is not considered a hazard at the project site,and no impact related to fault rupture would occur as a result of project development. Mitigation Measures No mitigation measures are required. ii) Strong seismic ground shaking? Strong, seismically-induced ground shaking resulting from earthquakes along nearby or distant faults represents the greatest seismic hazard at the Mountain House Community. The intensity of ground shaking at any particular location is a function of many factors including: (1) earthquake magnitude, (2) distance from the epicenter of the earthquake, (3) the duration of strong ground motion, (4) local geologic conditions (soil characteristics and topography), and (5)depth to bedrock. During an earthquake, structural damage at the project site may include damage to buildings and infrastructure (i.e., roads,pipelines, etc.). Earthquakes of magnitude 6.0 or greater are capable of causing widespread damage. As indicated in Table 4.6-1, above, active and potentially active faults in the vicinity of the project site are capable of producing earthquakes with magnitudes of 6.0 or higher. It is estimated that 16 earthquakes of magnitude 6.0 or greater have occurred within 62 miles of the project site between 1800 and 1999 (EDAW, 2005). Design and construction of the dwelling units at the proposed project would comply with the latest editions of the Uniform Building Code (UBC), the California Building Code,and Mountain House Community Services District(MHCSD) design; standards. With compliance to these codes and standards, structural damage from a strong earthquake would be minimized, particularly in wood-frame houses proposed for the proposed project. However, despite the implementation of mitigation measures in the MEIR and the policies of the MHMP, as well as compliance with applicable codes, the SPIIIEIR found the impacts related to ground shaking as significant and unavoidable and cannot be mitigated to a less- than-significant level. Mitigation Measures MEIR Mitigation Measure M4.6-1 (preparation of a Community Earthquake Preparedness Plan)promotes public awareness and education on earthquake hazards. This plan has been completed and is currently being implemented by the MHCSD. In addition, the MHMP includes Policies 6.5.1(b) (Emergency Preparedness) and 6.8.3 (Soils, Geologic, and Seismic Hazards). No additional mitigation measures are available that would change the conclusions of the SPIIIEIR. The impacts of ground shaking would remain significant and unavoidable. iii) Seismic-related ground failure, including liquefaction? Refer to discussion of Item a) i) above regarding ground rupture and Item a)iv)below regarding landslides. The potential for an earthquake with the intensity and duration capable 4-30