Sackung at Bald Eagle Mountain, central Colorado: An updated interpretation of ridge-spreading movement based on surveying and mapping from 1975-2022

USGS scientists have been investigating ridge-spreading and sagging (sackung in German) at Bald Eagle Mountain since 1975, when David Varnes and Dorthy Radbruch-Hall began surveying monuments to evaluate post-glacial ridge movement. More recent work has focused on continuing to survey the original monuments; using recently available lidar data to map sackung structures at a scale of 1:1,000; measuring structural discontinuities in the granite bedrock underlying the ridge; and integrating all measurements and observations into new interpretive cross sections showing ridge deformation. This presentation will describe these results and discuss their implications.

Coe (2022) Sackung at Bald Eagle Mountain, central Colorado: An updated interpretation of ridge-spreading movement based on surveying and mapping from 1975-2022. USGS Landslide Hazards Seminar, 09 November 2022.