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February 22,2016 <br /> Project No. T-7364 <br /> d: Any area which has shown movement during the Holocene epoch (from 10,000 years ago to the present) or <br /> which is underlain or covered by mass wastage debris of that epoch. <br /> e. Any area potentially unstable as a result of rapid stream incision, stream bank erosion, or undercutting by <br /> wave action. <br /> f Areas of historic failures, including areas of unstable, old and recent landslides or landslide debris within a <br /> head scarp, and areas exhibiting geomorphological features indicative of past slope failure, such as <br /> hummocky ground, slumps,earthflows, mudflows, etc. <br /> g. Any area with a slope of forty percent or steeper and with a vertical relief of fifteen or more feet, except <br /> those manmade slopes created under the design and inspection of a geotechnical professional, or slopes <br /> composed of consolidated rock. <br /> h. Areas that are at risk of landslide due to high seismic hazard. <br /> i. Areas that are at risk of landslides or mass movement due to severe erosion hazards. <br /> Existing topography on the grading and drainage plan indicates that localized slope areas along the natural <br /> drainage corridor are inclined at gradients between about 25 and 41 percent. As such, these slope areas are <br /> considered as having a medium and high risk of landslide hazard per items b(ii)and a(ii),respectively. <br /> In our opinion, the site conditions are not susceptible to landsliding. As discussed, we did not observe any <br /> indications of instability on the site slopes, and the slopes are underlain by inherently stable, dense to very dense, <br /> glacially consolidated till. Considering this, and that the slope areas will be eliminated incidental to the proposed <br /> project grading, it is our opinion that mitigation of potential medium and high landslide hazards are not <br /> warranted. <br /> 3.4.3 Seismic Hazard Areas <br /> Chapter 37.080.2 of the EMC defines seismic/liquefaction hazard areas as follows: <br /> a. Those areas mapped as seismic/liquefaction hazards per the Dames and Moore Methodology for the <br /> Inventory, Classification and Designation of Geologically Hazardous Areas, City of Everett,Washington: <br /> July 1, 1991. <br /> b. Those areas mapped as high and moderate to high liquefaction susceptibility on the Liquefaction <br /> Susceptibility Map of Snohomish County,Washington,Washington State Department of Natural Resources, <br /> Palmer, Stephen,et a1., September,2004. <br /> Based on the soil and groundwater conditions observed in the test pits, it is our opinion that the risk for damage <br /> resulting from earthquake induced slope failure, ground rupture, or soil liquefaction is negligible. Therefore, in <br /> our opinion, unusual seismic hazard areas do not exist at the site, and design in accordance with local building <br /> codes for determining seismic forces would adequately mitigate impacts associated with ground shaking. <br /> Page No. 5 <br />