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Resolution of MRS applied to the characterization of hard-rock aquifers.
- Source :
-
Ground water [Ground Water] 2006 Jul-Aug; Vol. 44 (4), pp. 547-54. - Publication Year :
- 2006
-
Abstract
- The performance of the Magnetic Resonance Sounding (MRS) method applied to the investigation of heterogeneous hard-rock aquifers was studied. It was shown using both numerical modeling and field measurements that MRS could be applied to the investigation of the weathered part of hard-rock aquifers when the product of the free water content multiplied by the thickness of the aquifer is >0.2 (for example, 10-m-thick layer with a 2% water content). Using a currently available one-dimensional MRS system, the method allows the characterization of two-dimensional subsurface structures with acceptable accuracy when the size of the subsurface anomaly is equal to or greater than the MRS loop. However, the fractured part of hard-rock aquifers characterized by low effective porosity (<0.5%) cannot be resolved using currently available MRS equipment. It was found that shallow water in the weathered part of the aquifer may screen MRS signals from deeper water-saturated layers, thus further reducing the possibility of investigating deeper fractured aquifers. A field study using the NUMIS(plus) MRS system developed by IRIS Instruments was carried out on an experimental watershed in southern India. A heterogeneous unconfined aquifer in a gneissic formation was successfully localized, and MRS results were confirmed by drilling shortly after the geophysical study. The top of the aquifer revealed by MRS was found to be in a good agreement with observed static water level measurements in boreholes.
Details
- Language :
- English
- ISSN :
- 0017-467X
- Volume :
- 44
- Issue :
- 4
- Database :
- MEDLINE
- Journal :
- Ground water
- Publication Type :
- Academic Journal
- Accession number :
- 16857032
- Full Text :
- https://doi.org/10.1111/j.1745-6584.2006.00198.x