2610 VIEWCREST AVE 2022-04-13 - Laserfiche WebLink

McCann Property Geotechnical Services Report 2610 Viewcrest Avenue,Everett, Washington Subsurface Exploration In order to confirm subsurface conditions on the property a series of 4 exploration pits were excavated on the property on March 23,2019. Logs of the exploration pits are attached with this letter. The location of the pits is shown on the attached site plan. All of the explorations encountered sand with silt to silty sand. Most of the sand was fine to medium grained but medium to coarse sand was observed in EP-1 and EP-2. The soils ranged from loose to medium dense to dense. Much of the loose soil may be related to past clearing and minor grading of the property. Mappings According to the Preliminary Surficial Geologic Map of the Mukilteo and Everett Quadrangles, Snohomish County, Washington, by Mackey Smith, 1976, Washington Department of Natural Resources,Division of Geology and Earth Resources,the site is mapped near the contact between as Vashon age advance outwash deposits, (Espersance Sand(Qe)and Vashon age glacial till(Qt). Our explorations are in agreement with the published geology map of the area as we did not encounter any glacial till but the underlying dense, sand and silty sand would be identified as Esperance sand. Seismic Hazards Generally,there are four types of potential geologic hazards associated with large seismic events: 1) surficial ground rupture; 2) seismically induced landslides; 3) liquefaction; and 4) ground motion. The site is located approximately 2 miles north of the northern splay of the South Whidbey Island Fault Zone. No surficial faulting has been noted anywhere near this area and the potential for surficial ground rupture during the lifespan of the residences is considered to be low. The building area slopes are gentle (8 percent slope gradient), are underlain by glacially consolidated sediments and do not present a risk of seismically induced slope movement. The underlying dense Esperance sand sediments especially in the absence of a ground water table, are not subject to liquefaction. Based on the encountered site conditions,seismic design criteria should follow 2015 International Building Code recommendations for Site Class D soils. CONCLUSIONS AND RECOMMENDATIONS Based on the results of our site reconnaissance, subsurface investigation and literature review it is our opinion that the subject site is suitable for the planned new construction. Gary A.Flowers,PLLC. 5205 23'd Avenue W Everett,Washington 98203 206-819-4304 2