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8.B. - Page 47 <br /> Faults that could affect the project site include the Monte Vista-Shannon Fault located appro�mately <br /> two miles southwest of the site and the San Andreas Fault located approximately three miles <br /> southwest of the project site. <br /> Liquefaction and Lateral Spreading <br /> Liquefaction is the result of seismic activity and is characterized as the transformation of loose water- <br /> saturated soils from a solid state to a liquid state during groundshaking. Lateral spreading is a type of <br /> ground failure related to liquefaction. It consists of the horizontal displacement of flat-lying alluvial <br /> material toward an open face, such as the steep bank of a stream channel. <br /> Redwood Creek borders the southern and part of the western perimeter of the project site. The site <br /> and vicinity have been mapped within an earthquake-induced liquefaction hazard zone by the <br /> California Geological Survey. A liquefaction analysis was completed for the site which determined <br /> that in general,the site is underlain by fine grained clay soils with low liquefaction susceptibility. <br /> The subsurface of the site does,however,have occasional sand layers which are highly susceptible to <br /> liquefaction. Should these layers liquefy in a seismic event,it is estimated that 1.09 inches of <br /> settlement could occur beneath the project site. The liquefiable layers are,however,located deep <br /> below the ground surface and the likelihood of the liquefaction-induced settlement affecting the <br /> surface of the project site is low. <br /> The project site is located adjacent to Redwood Creek which is concrete lined and has an <br /> appro�mate depth of eight feet. Groundwater was not encountered in soil samples at or above the <br /> level of the creek. Due to the presence of the concrete channel,the lack of saturated conditions at or <br /> above the level of the creek channel, and the presence of very stiff to hard clay soils in the upper 22 <br /> feet of the project site,the potential for lateral spreading at the project site is low. <br /> 4.6.2 Environmental Checklist and Discussion of Impacts <br /> GEOLOGY AND SOILS <br /> Potentially Less Than Significani Less Than Beneficial Information <br /> Significant With Mitigation Significant No Impact Impact Source(s) <br /> Impact Incorporated Impact <br /> Would the project: <br /> 1) Expose people or structures to <br /> potential substantial adverse effects, <br /> including the risk of loss,injury, or <br /> death involving: <br /> a) Rupture of a known earthquake � � � � � 1,2,8 <br /> fault, as described on the most <br /> recent Alquist-Priolo Earthquake <br /> Fault Zoning Map issued by the <br /> State Geologist for the area or <br /> based on other substantial <br /> evidence of a known fault? <br /> (Refer to Division of Mines and <br /> Geology Special Publication 42.) <br /> b) Strong seismic ground shaking? � � � � � 1,2,8 <br /> c) Seismic-related ground failure, ❑ ❑ � ❑ ❑ 1,2,8 <br /> including liquefaction? <br /> d) Landslides? � � � � � 1,2,8 <br /> 2) Result in substantial soil erosion or � � � � � 1,2,8 <br /> the loss of to soil? <br /> 1410 Valota Road Residential Project 35 Initial Study <br /> Redwood City January 2012 <br />