Figure 44 (a)--Geologic interpretation of east-west velocity model through the Seattle region, coresponding to profile AA' of Figure 4a and based on row 23 and nearby velocity sections. JdFc=Juan de Fuca crust; JdFm=Juan de Fuca mantle. Estimated error bars for isotherms are indicated near intersection of isotherms and JDFP. Red dots are earthquakes. Frictional states along the subduction thrust are indicated by line patterns in the legend (lower left in figure). Bold arrows denote upflow of fluids along the subduction thrust. Offshore geology constructed from seismic reflection and refraction results of Flueh et al. (1998).