PC-2025-16 - Laserfiche WebLink

Hana Japan Restaurant Project Initial Study/Mitigated Negative Declaration 41 May 2025 Other important active faults in the region include the Greenville fault located approximately 12 miles to the northeast of the site and the Hayward and San Andreas faults, located approximately 6.5 and 26 miles, respectively, to the southwest. During a major seismic event that causes ground rupture on a primary fault zone (such as the Calaveras fault), secondary ground deformations can occur in the region adjacent to the primary fault zone. For example, based on previous mapping reviewed by the Fault Exploration, a fault may exist to the southwest of the on-site trenching, beneath or to the southwest of the existing driveway. Therefore, the Fault Exploration report concluded that the potential for fault rupture in the area is high and recommended all structures intended for human occupancy be set back at least 25 feet from the existing driveway. As shown on Figure 8, although the building configuration has changed since preparation of the report, the proposed building location remains in conformance with the setback recommendations within the Fault Exploration report. In addition, the Fault Exploration included three exploratory trenches on the west side of the main trace. While the extent and magnitude of secondary ground deformations are difficult to estimate, most secondary deformations occur on shear zones or other faults located near the primary fault zone. Secondary faults or zones of fault related to shearing were not encountered during the trenching; therefore, the Fault Exploration report concluded that the potential for such ground deformations to occur at the proposed building is low. If secondary ground deformation did occur, the Fault Exploration concluded that such deformations would be small, less than four inches, and could be mitigated with appropriate foundation design and construction. The CBSC provides minimum standards to ensure that the proposed structure would be designed using sound engineering practices and appropriate engineering standards for the seismic area in which the project site is located. Projects designed in accordance with the CBSC should be able to: 1) resist minor earthquakes without damage; 2) resist moderate earthquakes without structural damage, but with some non-structural damage; and 3) resist major earthquakes without collapse, but with some structural, as well as non- structural, damage. Although conformance with the CBSC does not guarantee that substantial structural damage would not occur in the event of a maximum magnitude earthquake, conformance with the CBSC can reasonably be assumed to ensure that the proposed structure would be survivable, allowing occupants to safely evacuate in the event of a major earthquake. Conformance with the design standards is enforced through building plan review and approval by the City of Pleasanton prior to the issuance of building permits. Proper engineering of the proposed project would ensure that seismic-related effects would not cause adverse impacts. Therefore, a less-than-significant impact would occur related to seismic rupture of a known earthquake fault or strong seismic ground shaking. aiii,aiv. The proposed project’s potential effects related to liquefaction, landslides, lateral spreading, subsidence/settlement, and expansive soils are discussed in detail below. Liquefaction Soil liquefaction results from loss of strength during cyclic loading, especially as a result of cyclic loadings induced by earthquakes or ground shaking. Soils most susceptible to liquefaction are clean, loose, saturated, uniformly graded fine sands.