Exploration Technique: Gravity Techniques
|Exploration Technique Information|
|Exploration Group:||Geophysical Techniques|
|Exploration Sub Group:||Gravity Techniques|
|Parent Exploration Technique:||Geophysical Techniques|
|Information Provided by Technique|
|Lithology:||Distribution of density in the subsurface enables inference of rock type.|
|Stratigraphic/Structural:||Delineation of steeply dipping formations, geological discontinuities and faults, intrusions and the deposition of silicates due to hydrothermal activity.|
|Hydrological:||Density of sedimentary rocks are strongly influenced by fluid contained within pore space. Dry bulk density refers to the rock with no moisture, while the wet bulk density accounts for water saturation; fluid content may alter density by up to 30%.(Sharma, 1997)|
|Thermal:||Determination of potential heat source of the system related to the low density signature of molten intrusions. (Bruhn, 2010)|
- "Gravimetric studies may provide a constraint on the structure and extent of the geothermal reservoir, to a depth of ~2km. Fault location, dip and offset, as well as depth to basement, are commonly interpreted from a gravity survey. Changes in density may also be related to zones of hydrothermal alteration, intrusions, highly fractured rock or deposition of silicates in the vicinity of hydrothermal activity.'"`UNIQ--ref-00000000-QINU`"'<br><br>
Additionally, examining components of the gravity field can be useful in geothermal exploration. For instance, the horizontal gravity gradient enables identification of regions with the greatest contrast in density, such as at fault contacts. '"`UNIQ--ref-00000001-QINU`"'<br><br> Gravity techniques are also applied towards reservoir monitoring for subsidence and mass gain or loss within a geothermal reservoir using the microgravity technique.'"`UNIQ--ref-00000002-QINU`"'<br><br>[[File:ResidualBouguerAnomaly.jpg|frame|center|Residual Bouguer anomalies from the Taupo Volcanic Zone, New Zealand from the GNS database. '"`UNIQ--ref-00000003-QINU`"'" cannot be used as a page name in this wiki.
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Additionally, examining components of the gravity field can be useful in geothermal exploration. For instance, the horizontal gravity gradient enables identification of regions with the greatest contrast in density, such as at fault contacts. 
Gravity techniques are also applied towards reservoir monitoring for subsidence and mass gain or loss within a geothermal reservoir using the microgravity technique.
1 Gal=1cm/s^2=1000 mGal
Density is the physical property of interest for a gravity survey. Density is an intrinsic property of a material and is measured in mass per unit volume (kg/m^3).
- (Bruhn et al 2010) "Geothermal Energy Systems: Exploration, Development, and Utilization"
- (Blackwell et al. 2007) "Exploration and Development at Dixie Valley, Nevada: Summary of DOE Studies"
- (Cabezas 2010) "Precision Gravity Data of the Miravalles Geothermal Field: an Ongoing Assessment"
- ( Soengkono, 2011) "Deep Interpretation of Gravity and Airborne Magnetic Data of the Central Taupo Volcanic Zone "
No exploration activities found.