during 2000 through 2004 and water tank cut bench, near the concrete stairway and the toe of the slope to reshape the toe and construct the masonry block wall. The prominent cuts made along the lower portions of this pre-existing landslide have drastically decreased its resisting force and caused it to fail. On the other hand, surface infiltration into the surface cracks along Road A should not be primarily responsible for the 2011 reactivation based on our sensitivity analysis of the groundwater depth on the slope stability.
Grading to construct Road A performed early last century most likely removed the head portion of the pre-existing old landslide and decreased the driving force of the landslide. Repeated patching and sealing of the asphalt cracks by the County of Santa Clara most likely delayed its failure after the toe of the slope had repeatedly been encroached on and cut. Common knowledge in the engi- neering geology and geotechnical engineering profession that over- steepening and undercutting along lower portions of slopes to gradients exceeding about 2H:1V in Franciscan mélange is not considered acceptable by the Standard of Practice in this area, especially if adverse bedrock bedding occurs. The claim made by the Consultant A that water infiltration through the asphalt cracks after the re-alignment of Road A caused the failure lacks proper engineering geologic reason, judgment, and direct evidence as it is only based on speculation.