f SNMR test measurements in Austria

In December 1997 the NMR- method (NUMIS-equipment from IRIS-instruments) was tested the first time in Austria for groundwater research. NMR soundings were carried out in two different areas of Austria. The locations were chosen at sites where other geophysical methods, especially geoelectric multielectrode profiles, had been used before, to correlate the results with the findings of these methods. Unfortunately at location Pulkau the proton resonance frequency, calculated from the measured local magnetic field, was a multiple of the 50 Hz frequency. Therefore no reliable measurement was possible in that area due to the high background noise. In the area of Marz a total of 9 NMR soundings were carried out using both square loop and eight-shaped-loop. At two locations also no measurements were possible because of the high background noise of 6000 to 60000 nV. Only at the location “Marzer Kogel” reliable measurements were possible at some points, e.g the Paulinerkloster. In this area an intensive geoelectric research program was carried out for groundwater research purposes the year before. The results of the NMR sounding at the location Paulinerkloster are shown in fig.1. Here only the eight-shaped-loop gave good results. The inversion results show a constant water content of 20% between 12 and 50m. Two months before a multielectrode geoelectric profile was measured crossing the location of the NMR-sounding. The results are shown in fig.2. At the location of the NMR-sounding a high resistive area down to about 80 m can be seen. The results of both methods were so promising that in the summer of 1998 a borehole was made there. The results of the drilling fully confirmed the findings of the geophysical research. As the quantity and quality of water is sufficient, a local water supply station will be planned for the near future.