Variations in Lithospheric Thickness Across the Denali Fault and in Northern Alaska

While variations in crustal structure beneath the Denali fault in Alaska are well-documented, the existence of fault-correlated structures throughout the entire thickness of the continental lithosphere is not. A new model of shear-wave velocity structure obtained through joint inversion of surface wave and converted body wave data shows a northward increase in lithospheric thickness and velocity occurring across the Denali fault system. In northern Alaska, a dramatic increase in lithospheric thickness at the southern margin of the Arctic-Alaska terrane lies in the vicinity of the Kobuk fault system. These correlations support the view that transpressive deformation tends to localize at the margins of thicker, higher-strength lithosphere.