Permafrost thicknesses in the Oliktok Point, Prudhoe Bay and Mikkelsen Bay areas of Alaska

Abstract

An improved map of the thickness of ice-bearing permafrost in northern Alaska has been constructed by combining the previous data of Osterkamp and Payne (1981) with new data obtained by analyses and interpretation of recently released well logs. The new map provides greater detail and increased coverage, especially in offshore areas. Ice-bearing permafrost reached a maximum thickness of ≈ 629 m in three areas. This suggests that the permafrost thickness (depth to 0°C) may be on the order of 670–680 m. Permafrost thickness may be < 200 m and, therefore, can vary by a factor of about four. Thinning of the permafrost from the Prudhoe Bay area toward the foothills of the Brooks Range appears to be caused by the changing geology (through its effect on the thermal conductivity of the rocks) and the increase in mean annual ground surface temperature with distance from the coast. In the offshore area toward Reindeer Island, relatively simple models explain and give reasonable predictions for thawing of the ice-bearing subsea permafrost at the sea bed and for thawing at its base.