Petroleum and mineral resources play a major role in the daily lives of the
global population. Resource exploration and geological research is important
to maintain and enhance the quality of life to the global population through
the provision of materials for infrastructure, fuel for heat, cooking and
transportation, and through the insurance of protection from geological
Traditionally geological information for mapping at local and regional scales
has been acquired through field work by qualified geoscientists. Optical
remote sensing from air- and spaceborne platforms provide a synopic view of
the terrain which allows geological information to be collected over a larger
region. Geological information from optical sensors are however, hindered by
cloud cover, identification of features restricted by illumination conditions,
and the delineation of geological structure dependent on the angle and elevation
of the sun. However, over the past decades, radar remote sensing has proven to
be an effective tool for the extraction of geological information, unhindered
by external illumination and weather conditions.
The geological interpretation of radar imagery at a regional scale is based on
the analysis of surface morphology at the terrain and landform level. The use
of radar data for topographic mapping has been well documented (Simonett and
Davis 1983; Williams 1983). The side-looking configuration of spaceborne SARs
highlight relief; the use of shallow incidence angles produces a shading effect
or shadowing which can emphasize even subtle slopes in the landscape. These are
often attributable to underlying geological units and structures.
Other remotely sensed data can be integrated with SAR data to provide additional
information for an imaged area, thus creating an enhanced image map for
interpretation. Landsat TM optical data adds vegetation information which allows
for geobotanical correlations to be developed. Information about underlying soil,
sediment, and bedrock conditions can be inferred from surface vegetation, although
the successful application of this technique requires extensive, study
area-specific background information. Another valuable combination is with the
varied data sets generated by modern geophysical surveying--widespread in mineral
exploration. Combined with radar imagery it provides a means of correlating, or
at least locating, inferred subsurface mineral horizons, structural features, or
lithologies with respect to surface relief.
Radar-derived geological information is used by experts involved in a wide range
of geological applications including geological and quaternary mapping, mineral
and hydocarbon exploration, and geologic hazard identification.
Radar is particularly well suited for geological mapping because of the terrain
texture information it provides which are often related to geological structures
and surficial deposits. These features are often manifested topographically at
the Earth's surface; the side-looking configuration of radar enhances differences
in relief which may aid in the delineation of such features.
Quaternary mapping in glaciated terrain, which involves the delineation of
landforms together with the assessment of surficial material, has been
successfully demonstrated using radar alone and in combination with optical remotely
sensed data. The radar data provides information on topography of landforms, from
which many Quaternary features can be identified through their characteristic
morphology. The optical data provides information on natural vegetation cover
which may be related to conditions such as soil/sediment drainage, clay content,
etc. In combination with conventionally derived Quaternary maps, radar data can
allow regional extrapolations of surficial deposits which can then be used for
infrastructure route planning and aggregate resource assessments.
Radar has also proven to be a promising tool for mineral and hydrocarbon
exploration. Certain types of mineralization and hydrocarbon resources are often
associated with specific geological structures thus, the mapping of these structures
when topographically expressed can assist in the identification of areas of high
mineral and hydrocarbon potential. Often radar data are merged with geophysical
data. The radar data allows the delineation of topographically expressed structures,
while the geophysical data aids in the identification of strong magnetic signature.
Resulting composites show the correlation between geological structure and magnetic
anomalies which aid in the planning of detailed ground surveys.
Geologic hazard identification is an important part of geological research as it
pertains to the safety of humans, as well as to the protection of the environment
they inhabit. The identification of seizmic zones, and the assessment of landslide
hazards and coastal erosion has been successfully demonstrated using radar.