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Geophysical & Non-Destructive Technologies
Microgravity surveying (Gravity) is a valuable tool to characterize subsurface karst
features. It can be utilized in urban areas where cultural features and noise limit other techniques like seismic and resistivity. Gravity can map and identify preferential flow paths associated with fractures zones and large cavity systems.
It can also be used for the identification and characterization of potential collapse
features due to karst sinkhole activity or mine subsidence. Most potential collapse
features have no recognizable surface morphology until there is a catastrophic failure
and a collapse occurs. Since air filled voids have sufficient lateral density contrasts
from surrounding bedrock and soils, microgravity can be a rapid and inexpensive means
of identifying potential collapse features.
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Applications:
- Karst related cavities and solution channels
- Void Identification
- Sinkhole Delineation
- Mine Subsidence Mapping
- Buried Valley Identification
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Microgravity surveys are used to identify lateral variations in the subsurface soil
and rock density, which are influenced substantially by the size and depth of the
target. The infield gravity, elevation, and time data are processed and a Bouger
Gravity Anomaly map is produced. This map shows local relative gravity lows, which
indicate areas of less dense materials (e.g., potentials voids, sinkhole throats)
located under the survey area.
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