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Mr. .iames (iallc�way <br />` SeE�tember G, 2p1 1 <br />The follo«�inr rccoinmendatians are based on desi�,�,n features as w-e understand thein. If actual feat��res vary or <br />chan�es are made, ��-e should be info�-�ned and allo�ved to revieu� the chan`,es in order to ainend or supplement our <br />1'CCO]I1111CI1di3110115, as requlred. <br />SITE CONDI'1'IONS <br />�urfacc <br />Tl�e locatic�n af tl►c addition relative to the existir�r buildin� and site features site i� sho�vn on attached Fi�ure 1. <br />Surfacc grades over most oi� the addition area arc re;latively flat about sis inches belour the elev�tion of ihe <br />bi�ildir7� flac�r slab. I�i the easteri� partic��i of' tilc additiou site grades desc��►d to tl►c east ���itll and overall dre�p c�f� <br />about four %et. There is ,�n exisfing yard drain that c�ptures �unoff' from tlfe arca for conveyance to the storm <br />cirainage systc;m. <br />Thc; aciditic�n area is ��e�etated �vith lawn tl�at is maintained. The adjacent sE�pe is vegetated ���ith iall �;rass, scotch <br />broom, so�lle sn►all trees, and blackberry. Obser��ations of the slope nated rlo evidenee of n�oven�ent or er'c�sic�ii. <br />W(', i1C)ICCj SOIIlZ AI'eAS Of eX�iOSet� SOI�S COIll�)OSeC� Of S811Ci \VIZ�l SIlI �311(� `,?ravcl alont� the i�}idcile �liird portio�i of the <br />slope face. <br />Sui�surface <br />i1s noted in the referenced rep�rt, sozl coi�ditions observed in test pit exc�vations consisted of one lo l�vo feet oi� <br />till composed of silty sand «-ith gravel o�-erlyin� native sand and gravc;l ���ith varying tines (silt and clay} contenl. <br />The upper (ill �vas noted to be in a niediuni dense, relativety co�npact conciition. The underlyin� native soil was <br />noted to be in A I11C'(�lll[ll dense to dense conditioii. Grouildwater seep��c �vas not obseived in the test ��its. <br />Ho�vever, moist tc� ti-et soils «rere noted at a depth oI� ahout nine feet below site rrade. <br />�u�� �eologic i•ec�nilaissance of the site ge3ierally ca�ltir�iis sail cotlditic�ns as described in t17e referetic�d r'epart. <br />C?bservations of soil ex���sures along the �outh slope r�oted that thc II�IIVC s�nd �vith silt and �ravel lornlation <br />appears c;cmtinuous benealh the site. \'Ve did not obser��e any evidence of �rour�d�vater seepa�c on lh� s]�pe, <br />�vhich indic��tes that static or perched +�round�v�ter c9oes nat reside beneath ihc site. <br />Gk,OLOGIC IEA%AIZDS <br />Seismic <br />Liquefactioii is a phetiamerio�l «�her�c tE�er� is a reduction or complete Ioss of soil strengtli due ta arl ii►crease i►� <br />�4ater pressure induced by ��ibra[ions, Liquefaction tnainly affects geologically recent deposils of tine-grained <br />sands that are belo�v the ground«�ater table. Soils af this naturc, c�erive their strcn�th from intergranular friction. <br />The �,enerated �vater pressure or pore pressure essecltially separates the sail grains and eliminates this <br />inter�,i�anular fi�iction; thus, eliiniiia[iaig tlle soil's strengtl�. <br />Clia�tes• 37 oi'the City of Everett Mwiici��l Code (EMC} defines seismic/liquefaciion areas as follours: <br />• Those areas mapped as seiscriic!lic�uefactio�i l�azards ��er the Dacl�es and �ioore ?��lethodofogy for tlle <br />(nv�nlory, Classitication and Desigiiatic�n of Geologically Hazardc�us Areas, City of Everett, Washin�;lon: <br />July 1, I 991. <br />• Thosc areas mapped as hi�l► anci inoderatc lo high liquef'�etioi� susce�tihility on tlie Liyuelacticm <br />Susccptibility Map oF Snohomish ('ounty, Washin�ton, Wasl�[ti�to�� State Uepartmetit c�I� Nattu��l <br />Resources. Paimer, Stc�hcn, �t al., Septetubcr, 2004. <br />Projc;ct No, "I�-S471-2 <br />Pace No. 2 <br />