Remote sensing data. should not simply be added to the 
usual procedures, but should be evaluated prior to collecting 
other data. The results should then be used to plan the 
intensity and pattera of subsequent field work. One should 
not, however, assume that remote sensing will resolve all 
the problems associated with geologic and environmental 
Studies. It should be remembered that remote sensing is 
only a tool, albeit a very sophisticated one, and that field 
verification and interpretation by highly trained observers 
and/or scientists is still necessary. However, it does 
enable the investigator to define the more important areas 
of concern quickly and at low cost. 
Scope of Remote Sensing in Geologic Investigations 
An analysis of remote sensing imagery for the linear 
features that trend toward or surround a prospective site, 
should provide the starting point in a site investigation. 
It is critical to the viability and safety of the site that 
all linears, so identified, be properly associated (or dis- 
associated) with known geologic structures as far as geometry, 
sense of movement and age relationships are concerned. The 
Landsat investigation should be conducted for a 200 mile radius 
about the site which necessitates mosaicing several scenes. 
All known epicentral locations (earthquakes) should then be 
plotted on a base prepared from such a mosaic and related 
to known and/or suspected geologic structures. Depending on 
coincidence or similarity with known structures; site related 
structures may then be identified for detailed investigation 
and dating. After identification from satellite imagery 
other remote sensing imagery and/or other input data such as 
aeromagnetic and gravity contour maps can also be applied 
along with field investigation. The purpose is to 
determine the possible significance of the geologic structures 
to site safety. 
This information can be presented via overlays to stan- 
dard maps of a given project area.  Correlations are then 
made between linears (from satellite data) and known fault 
traces as shown on existing geologic maps. In this way 
linears which may have been compiled as reflections of man- 
made features i.e. roads, railroads and canals, can be elimi- 
nated; and by virtue of the broad view afforded from satellite 
altitudes, known fault traces can be extended and new lin- 
eations heretofore undetected, added to the store of geo- 
logic information in the region. 
In addition to the linear compilation, supplementary 
annotations showing surficial geologic contacts are shown. 
These can be compiled using the existing geologic maps as a 
means of identifying lithologic/soils formations. The identi- 
fication of stratigraphic contacts, having a linear expression 
can frequently remove the linear from consideration provided