Geology Reference
In-Depth Information
trial pits and boreholes, as necessary. Conversely, a ground investigation in an area of variable topo-
graphy, without prior API, reconnaissance and desk study, may be ineffective and poorly focused. An
introduction to the use of air photographs, with particular consideration of landslide investigations, is
given by Ho et al. (2006).
Air photos used to interpret the
nature of terrain, landslides and
site history
Geomorophological interpretation
of terrain units with association
constraints and need for GI
Figure B4-3.1 Process of API. Pairs of overlapping photographs can be examined stereographically to give
a 3D image. Major terrain features can be identi
ed and if historical series of photographs are available,
then land development and site history can be ascertained, in this example, in terms of landslide history. In
the second image above, interpreted landslides have been mapped (with date of the photo in which the
landslide is
field (Devonald et al., 2009).
In addition, terrain can be split into units on the basis of surface expression, underlying geology, activity and
vegetation, as described by Burnett et al. (1985). Third photo and overlay provided by K. Styles.
first seen). These interpretations can then be checked in the
Victoria Falls
of Zambezi River above Victoria Falls between Zimbabwe and Zambia.
