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CONCLUSION 
All landslide investigations must start with either the recognition of 
a distressed condition on the natural or artificial slope or the 
determination of the vulnerable locations where one is most likely to 
occur. The evidence for distressed conditions that may be present or 
induced lies chiefly in evidence of movements, minor or major, that 
have already taken place or of geologic, soil, and hydrologic condi- 
tions that are likely to cause movement in the future. Once the fact 
of land movement, actual or potential, has been established, the next 
essential step is to identify the type of landslide. One would not 
apply the same corrective procedure to a rock fall and a block slide 
any more than one would attempt to prevent a slide without knowing the 
kind of slide expected. If maximum benefit is to be accrued from the 
preventive or corrective measures finally employed, it is imperative 
to learn to recognize the kind of slide that exists or is expected. 
Remote sensing is an effective technique for recognizing and delin- 
eating landslides. No other technique can provide a three-dimensional 
overview of the terrain from which the interrelations of topography, 
drainage, surface cover, geologic materials, and human activities on 
the landscape can be viewed and evaluated. Aerial photographs at 
suitable scales are available for almost all of the United States and 
a large part of the world. New photography of various types and scales 
can readily be obtained. In addition, new sensors such as infrared, 
radar and satellite multispectral systems provide new information as 
well as complimentary data which aid in analyzing the terrain for 
landslide presence or susceptibility. 
The general procedure for performing landslide investigations using 
remote sensing techniques is described in the paper. The recommended 
approach for performing the investigations include (1) starting with 
the analysis of the regional geology and terrain, usually on small- 
scale photography or imagery; (2) followed by a more detailed analysis 
of the terrain on medium-scale photography or imagery in order to 
identify the geologic units and landforms where landslides are present 
or are most likely to occur; and (3) concluded by a detailed study of 
vulnerable locations on large-scale photography and imagery to search 
for signs of potential instability. This approach requires the analysis 
of at least two different scales of photography and/or imagery. 
Additional remote sensing coverage may be required to evaluate the 
slide historically (i.e., before and after), or to note the progress 
of additional movement with time.