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Subsurface Exploration,Geologic Hazard,and <br /> JanowGeotechnical Engineering Report <br /> Everett, Propertyas Geologic Hazards and Mitigations <br /> Everett,Washington <br /> • Fills should not be made over colluvium or landslide deposits. <br /> • Any stormwater runoff entering the site should be captured and directed away from <br /> slopes, retaining wails, or foundations. Runoff from the site should not be permitted to <br /> discharge near the top of or over the lower'steep slope, Impervious surfacing should be <br /> minimized to reduce quantity of runoff generated onsite. <br /> • Native vegetation should be maintained in any unbuilt areas and particularly near the <br /> top of slope. <br /> Further recommendations are presented in the"Preliminary Design Recommendations"section <br /> of this report. However, it must be understood that no recommendations or engineering <br /> design can yield a guarantee of stable slopes. <br /> 6.0 SEISMIC HAZARDS AND MITIGATION <br /> Earthquakes occur regularly in the Puget Lowland. Most of these events are small and are not <br /> felt by people. However,large earthquakes do occur, as evidenced by the 2001,6.8-magnitude <br /> event; the 1965, 6.5-magnitude event; and the 1949, 7.2-magnitude event. The 1949 <br /> earthquake appears to have been the largest in this region during recorded history and was <br /> centered in the Olympia area. Evaluation of earthquake return rates indicates that an <br /> earthquake of the magnitude between 5.5 and 6.0 is likely within a given 20-year period. <br /> Generally, there are four types of potential geologic hazards associated with large seismic <br /> events: 1) surficial ground rupture, 2) seismically induced landslides, 3) liquefaction, and <br /> 4)ground motion. The potential for each of these hazards to adversely impact the proposed <br /> project is discussed below. <br /> 6.1 surficial Ground Rupture <br /> The nearest known major fault to the project site is the South Whidbey Fault Zone located - <br /> approximately 4 miles to the south. The South Whidbey island Fault Zone is also thought to be <br /> an active fault zone capable of producing surface ruptures, though research of this fault zone <br /> near the project is preliminary and limited. Due to the distance from the site to the known fault <br /> zones the risk for damage to the project during the expected life of the structures due to <br /> surface faulting is expected to be low,in our opinion. <br /> ASSOCIATED EARTH SCIENCES,WC.May 10,2018 Page 7 <br /> tom-170649E1J02-2-Projecis1202706491KE WP <br />