A STUDY OF THE EFFECTS OF GLACIAL LAKE ALBANY ON LANDSLIDE ACTIVITY IN THE HUDSON RIVER VALLEY

The effects of the Laurentide Ice Sheet and glacial Lake Albany can be seen throughout the Hudson River Valley. Deposits of silt and clay from the lake and deltas of rivers leading into it have set the foundation for very unstable lithology. This paper will discuss the connections between glacial Lake Albany and the volatile landslide history of this region through factors such as sediment grade and effects of rainfall. The most common landslide in this region is the rotational landslide which has a concavely sloped surface of rupture where the sediments cede to gravitational force and experience a slide movement rotational about an axis. Sediment profile and dip of the slope data collected from an at risk site; the hill at the Rensselaer Polytechnic Institute campus along 8^th street on which Carnegie Hall, Pittsburgh Hall, and EMPAC are built, will be used to determine under what conditions the slope is at risk to fail and undergo a rotational landslide movement. Inspection of boring logs indicates there is a point of concern at a depth of about 6 to 8 meters below the top of the slope where the sediment profile is a “wet and loose silty clay.” This section is most at risk because a period of heavy rain can cause it to go from “loose and wet clay” with an angle of repose of 20-25 degrees to “puddle clay” with an angle of repose of 15-19 degrees. If the clay becomes too loose and saturated with water, the angle of repose may fall below the current angle of the slope which is an average of 21 degrees, the slope will be in danger of mass wasting. An additional danger is the construction of Pittsburgh Hall and Carnegie Hall on the hill in the 1800s and EMPAC’s recent construction in 2003, adding pressure to the slope and potentially raising the damage costs if the slope were to fail.