1111 CRAFTSMAN WAY 2016-01-01 MF Import

I3 inches of asphalt concrete over G inches of crushed surfacing base course. The base course should be compacted to at Ieast JS percent of the MDD(ASTM D-I557). � We recommend using Class B asphalt concrete material diat conforms to Section 5-04 of the \Vashington State Department of Transportatiun (�VSll01') Standard Specifications. The base course and A1'E3 malerial should conform to Section 9-039(3)and Section 4-OG, respectively. i These pavement sections and recommendations for temporary protection may not be adequate for hea�y construction traRic conditions such as imposed by concrete transit mixers, dump trucks or cranc lo:�ds. I Additional subbase ur paeement diickness may bc necessary to prcvent pavemcnt damagc d�innc wnstruction, and/or repair of damaced pacements should be anticipated. �I SEISMIC CONSIDERATIONS Seismicity i IGeneraL Wcstern �Vashington is considered a moderate to high scismic rceion. Three potcntiaf scismic source zones are generally aceepted for westem �Vashington: (1)shallow crustal earthquakes associated i with known ancUor unl:ne�vn faults; (2) Cascadia SuUduction Zone interface eardiquakes, ��hich occur along Ihe boundary located behveen thc Juan de Fuca and North American platcs; and (3) Cascadia Subduction Zone intraplatc �arthquakcs, which occur within the subducting luan de ruca Plate. Shallow Crustal Earth uakes. Shallo�e crustal earth uakes occur �vithin the North Amcrican Plate to 9 9 depths up to l5 m;les. Shallow earthquakes in westcrn �Vashington are expccted to have durations ranging up to GO seconds. Irour magnitude 7 or grcater kno��n earthquakes have occurred in the last I1,100years in the Cascadia region, h��o of these occurred on Vancoin•er (sland and t��o in �vestcm \Vashington. i The largest historic earthquake in westem Washington occurred in IS72 in the North Cascades and is estimated to have had a magnitude of 7.4. This carthquake is belic��ed to ha�c occuRrd at a depth of Icss than 10 miles. The othcr magnitudc 7+ ��estcm 1\'ashington e�rthyuak� uccurreJ un thc Scatdc Pault approximately 1,100 years ago. Several other surface faults have becn idcntilicd in dic Pugci Sound region bui ha�c not bcen studicd in dctail to date. The shallow fault mapped neares[ to the site is the �Vhidbey Island Fault, a northwest-southeast trendinb structure down-thrown on the northeast side (USGS OPR 99-3S7, 1999). Geologic maps indicatc that the \Vhidbcy Island Fault is lacatcd roughly 2 miles north oP the site. Liccause of thc thicl:ncss of thc Quatemary sedimcnts bclow the site, ��hich are commonly more than 1,000 fcet thick, and the distancc ro the ncarest mapped fault, the potential for surface faul[nipwre a[ thc site is considered remote. Cascadia Subduction 2one Interface Earthquakes. Interface earthquakes occur on the boundar}• bet��cen the Juan de Puca and North American tectonic plates. 7'he Cascadia Subduction Zonc extends from Vancouver Island to Northcrn CaliCornia. Interfacc e�rthquakes on the Cascadia Subduction Zonc are anticipated to have durations ranging up to 4 minutes. There is no historical record of large subduction zone earthquakes oCf the coast of �Vashington. However, paleo geologic ecidence of thc occurrence oflarge (magnitude 8 to 9+) carthyuakes occurring on the Cascadia Subduction Zone has recrnUy becn discovered. Thc last large interface earthquake is bclieved to ha��c occurrcd in the year 1700, and it is es[imaled that approximately sevcn events may have occurred o��er thc last 3�00 ycars. It � I'J�•A'o. I?GS'�0111�00 Page 6 GEOENGINEERS� ,A'nrrut6rr/. .'OOC