4711 GLENHAVEN DR 2016-01-01 MF Import

.. - motion. The potential for each of these hazards to adversely impact ffie proposed project is discussed below. 6.1 Su�cial Ground Rupture Generally, the largest earthquakes which have occurred in the Puget Sound area are sub-crustal events with epicenters ranging from 50 to 70 kilometers in depth. For this reason, no surficial , faulting, or earth rupture, as a result of deep, seismic activiry has been documented, to date, in the Snohomish Counry region. Therefore, it is our opinion, based on existir� geologic data, that the risk of surface rupture impacting the proposed project is low. 6.2 Liquefaction • The encountered sediments are judged to have a low potendal for liquefaction during a seismic event due to their medium dense to dense, granular consistency at shallow o.:pths and the lack of a high ground water table. 6 3 Seismicall�Induced Landslides Under the conditions observed during our explorations, it is our opinion that there is a moderate risk of seismically induced landslides impacting the site. The exiscing fill soils located on the site's south perimeter slope are loose and currendy exhibit signs of instability. Therefore, the fill slope could experience shallow-seated landsliding as a result of a strong earthquake. Construction of die proposed residence should not increase the risk of landsliding within this slope provided d�at the recoromendations contained in this report are followed. Since the residence will be located north of the toe of the Fil( portion of the slope, the proposed foundation excavation sliould not undermine and destabilize the exis[ing fill slope. Additionally, coastruction of the proposed parl:ing area retaining walls, and improvemenu to site drainage which should prevent ntnoff from upslope properties from flowing over the crest of sire slopes, should enhance the stabiliry of the fill slope. It must be understood that due to the inherent sloping nature of the lot and noted movement within the fill slope, a heightened earth movement risk will always remain. Engineering design can reduce, but not eliminate this risk. Therefore, [o locate the new structure in the most naturally stable area of the site and in an area of Ieast impact on slope stability, we recommend d�at thc residence be located within the northwestern section of the proposed building site, and not encroach �vithin die fill slope to the �^uth, as shown on the Si[e and Exploration Plan, Figure 1. 6.4 Ground Motion Based on the site stratigraphy and visual reconnaissance of the site, it is our opinion that any earthqual:e damage to the proposed strucmres founded on <. suitable bearing strata, and 6