Late Quaternary sea-level changes and palaeoseismology of the Bering Glacier region, Alaska

Glacial isostatic adjustment and multiple earthquake deformation cycles produce temporal and spatial variability in the records of relative sea-level change across south-central Alaska. Bering Glacier had retreated inland of the present coast by 16 ka BP and north of its present terminus by ∼14 ka BP. Reconnaissance investigations in remote terrain provide new but limited insights of post-glacial relative sea-level change and the palaeoseismology of the region. Relative sea-level was above present ∼9.2 ka BP to at least 5 ka BP before falling to below present. It was above present by the early 20th century, before land uplift in the 1964 M 9.2 earthquake. The pattern of relative sea-level change differs what may be expected in comparison with model predictions for other seismic and non-seismic locations. Buried mud–peat couplets show a great earthquake ∼900 cal BP, including evidence of a tsunami. Correlation with other sites suggest simultaneous rupture of adjacent segments of the Aleutian megathrust and the Yakutat microplate.