Figure 9. Probability distribution histograms (using OxCal v. 3.0, Ramsey, 1995; based on Stuiver and Reimer, 1993) of the calibrated radiocarbon ages of the Snohomish River samples (Table 1) compared to known or inferred paleoseismic events in Puget Sound and the Pacific coast of southwest Washington. Geologic data from the southern Puget Lowland area (SP) suggest that more than one crustal earthquake shook the region about the time of the Seattle fault (SF) earthquake (Bucknam and others, 1992; Sherrod, 1998; Atwater, 1999). "LW" events indicate approximate time (uncertainty is unknown) of turbidite deposition in Lake Washington, which Karlin and Abella (1996) infer is related to earthquake-induced slumping. "F" indicates time of significant earthquake-induced liquefaction on the Fraser delta (Clague et al., 1997). "Y", "W", "U", and "S" are buried soils in southwest Washington inferred to record rapid subsidence during subduction-zone earthquakes (Atwater and Hemphill-Haley, 1997).