Notes
Memorandum dated January 25, 2001 from Douglas Lindquist (EIT) and Michael Bailey (P.E.) of Hart Crowser, Inc. to the Embankment Technical Review Board (Attn: Pete Douglass), project J-4978-30, CC to Jim Thomson (P.E., HNTB). Provides additional information on seismic analyses for the Third Runway at Seattle-Tacoma International Airport (STIA) in SeaTac, Washington. Covers probabilistic seismic hazard analysis (PSHA) conducted with subconsultant Professor Steven L. Kramer, seismic sources (shallow crustal sources 25-30 km depth, deep Juan de Fuca subduction zone 45-70 km), Gutenberg-Richter Recurrence Law, attenuation relationships, one-dimensional site response analysis, liquefaction potential, and seismic stability and deformation analyses. Discusses Puget Sound Basin, Olympic Mountains, Willapa Hills, Southern Cascades, Northern Cascades, and Vancouver Island physiotectonic zones. References Gardner and Knopoff (1974) aftershock procedure and Ludwin et al. (1991) completeness intervals. Seismic hazard level: 10 percent probability of exceedence in 50 years (475-year return period).