Slope Stability Report (4) · EXE22/0020

Specialists in transport geotechnics

Slow, creeping landslides and historic events may be recognisable by consistently bent trees; as
the ground moves and tilts the trees will continue to grow near vertically, which can lead to a kink
in the trunks – this will be exhibited by a number of trees and single specimens are not likely
representative of slope movements. Creep and lateral spread in low-angle slopes may be seen
by linear irregularities in the slope.
Historic landslides may also be picked up in high-resolution topographic maps: downslope lobes
and hummocks can often be seen, and when combined with irregularities in the slope and gullies,
can identify areas which warrant further investigation.
Anthropogenic features may also be disturbed by landslides; powerlines may be tilted, retaining
walls can bulge, roads and railway lines may show cracking and offset.
Sometimes, areas which are in danger of developing landslides can be picked up by the
formation of tension cracks and the presence of springs and altered drainage, however, for the
most part these areas need to be assessed by considering a combination of slope angles,
material types and assessing the risk from historical records and context.




9 August 2022                     CGC-SR-2022-012-R01-Rev01                                  Page 7