Fracture-trace, or lineament analysis,
is a powerful ground-water exploration tool used by AGW scientists.
Fracture-trace analysis is a photogeologic method.
It is based on the fact that the crust of the earth is very highly fractured
and faulted. The fractures and faults are activated daily as the
crust of the earth rises and falls in response to tidal effects.
The slight movements along the fractures and faults propagate to the land
surface where they disturb the surface soils. These soils are
commonly more porous. The linear zones of more porous soil contain
more moisture and hence more vegetation.
Fracture-trace analysis depends on locating lineaments
on aerial photographs and then locating them on the ground. In some
cases, they represent major fault traces. They may be evident on
high resolution satellite imagery and through geomorphic expression on
AGW scientists have successfully used these methods
for more than 40 years. We have taught this method to hydrogeologists
in West Africa funded by the U.S. Agency for International Development.
The fracture-trace analysis is most applicable in areas of crystalline
rock terrane such as limestone, granite and metamorphic rock.
A case study dealing with fracture-trace
analysis is included on this web site. The success of ground-water
exploration programs using satellite imagery and infrared imagery from
the Landsat Thermal Mapper is discussed in relation to projects in Ghana
in several articles in our library.