Rapid active thrust faulting at the northern Alaska Range front

Plate convergence rates strongly influence seismicity and mountain building inboard of convergent margins, but the distribution and kinematics of structures accommodating farfield convergence can be elusive. In interior Alaska, Yakutat microplate convergence drives late Pleistocene–recent right slip on the Denali fault, but westward-decreasing slip rates leave substantial residual Yakutat motion unaccounted for. Here, we show that Northern Foothills thrust slip beneath the northern Alaska Range absorbs a modern 4.4 mm/yr geodetic velocity gradient equivalent to ~78% of the 5.6 mm/yr residual Yakutat convergence along the central Denali fault. Infrared-stimulated luminescence ages of strath terrace deposits (67–4 ka; six sites) quantify Totatlanika River bedrock incision across the 1947 M_w 7.1 thrust earthquake epicentral region. Incision rates increase abruptly from