2.2 Location of a Fault Zone

During the realization of the Munich project, it was absolutely necessary to find appropriate test sites for the "walk-way" experiments. On one occasion, it was possible to link this aim with a localization of a site intended for a deep well in a valley of the Spessart, situated in central Germany. The geological conditions in that region were partly known from several dozen deep drillings which were sunk to 650 m; below the subsoil which carries surface water not of interest here, New Red Sandstone, Zechstein and Rotliegendes dominate. Since only two of the numerous deep drillings encountered water, it must be concluded that the hard rock exhibits only low, partly no permeability. Nevertheless, the assumption appeared justified that a fault system was present in the valley which might offer adequate sites for the required deep wells. No knowledge about the position of this fault was available; this lack of information can also be inferred from two more recent deep drillings which remained totally dry.

The GTZ expert, Hans Schröter, was informed about the situation. Under scientific supervision he used the dowsing technique to try a location of the fault in the target area, which was about 10 km long and 2 km wide. In addition, he determined smaller faults extending almost perpendicular to the main fault. At one of the intersections so defined he indicated an optimum drilling point (P).

Another dowser, who had a long experience as scientifically working geologist, was confronted with the same task, but without being given any knowledge about the indications produced by Schröter. To general surprise, he located the fault nearly identically. Due to this coincidence, it was decided to integrate the located point P into a test course for the "walk-way" experiments of the Munich group. The subsequent experiments performed at this site with many other dowsers led, in fact, to highly significant results. The preferential points indicated by the test persons often differed from point P by less than 1 m, either before or behind P — this corroborates the assumption that P signifies an anomaly in the subsoil. In view of these promising results, a check up of the area was arranged in which three different geophysical prospecting methods were employed around the point P; these were electrical soundings (electrical resistivity of the underground), radioactivity of the upper rock formations, and the seismic movements of the top soil. Remarkably, these three objective measuring procedures also supported the particularity of the point P located before by dowsing techniques.

Fig. 10. Experiments carried out by dowser R1 (scientific geologist) and R2 (GTZ expert Hans Schrter) in order to locate fracture zones in a Spessart valley. Above: area to the north of an existing well Q; Q fault zone obtained from dowsing procedures; F: earlier unsuccessful drilling; V1, V2: perpendicular faults indicated by dowser R1; P: drilling point proposed by R2; RO: drilling point proposed by a third dowser. Beneath: fault zones predicted by R1 and R2 in an area to the south of the well Q.

Geo-Electrical Soundings. As position and direction of the fault zone had to be considered as being fixed by the dowsers, geo-electrical investigations could be conducted relatively quickly in the proximity of the point P (asymmetric procedure in the form of the reduced Schlumberger method by utilizing a single moving electrode). As it had already been observed within several other parts of GTZ projects in Sri Lanka, the present results of the measurements could also be interpreted as a verification of the findings produced by the dowsing technique: longitudinal and intersecting faults were found as predicted; only with respect to the exact direction of the transverse faults did some less significant deviations show up [19].

Radiation Measurements. The gamma radiation of the potassium-40 activity of the soil has been detected along several lines on the slope, oriented parallel to the main fault in the valley. At certain positions, all profiles exhibited a sharp intensity step; these points could be linked by a line which, when extended towards the direction to the valley, missed P by only 15 m [19]. Such a relatively small deviation does not deserve too much attention, especially because the dip angle of the fault (relative to the vertical) was not known and might play a certain role.

Seismic. Measurements of the ground vibrations were performed by means of two highly sensitive geophones (Type Mark L4) of the same model and equally calibrated, which had been installed at the point P and at a small distance of 2 m from P (second measurement: 4 m from P). The geophysics experts who carried out the experiment did not expect that oscillations, measured at sites separated by only a few meters, would differ by significant amounts; the wave lengths expected for the vertical and longitudinal oscillations lie, due to the influence of the known sediments in the valley, at about 30 m and 75 m, respectively. With a maximum amplitude below 1 m/s, the registered vibration velocities were within the usual range. The big surprise was that the vertical oscillations around 20 Hz displayed a considerably higher amplitude at the point P than only 2 m or 4 m further away. This clear difference demonstrated once more an anomaly of the underground at P [20].

Fig. 11 Geoelectrical soundings and gamma-ray measurements in the environment of the point P. - - - - fault locations determined by the geoelectrical procedure (circles, triangles and squares represent different conductivity in the underground); - Q - Q - line connecting the points where sharp changes of the radiation intensity emitted from the rocks have been measured.

Fig. 12. Frequency distribution of the seismic vibration measured simultaneously at two points, which were separated by only 4 m. The point P is the drilling point determined by GTZ dowser Hans Schrter.

The results gained from these specially arranged experiments are not at all sufficient to establish a clear correlation between the three indicated types of physical signals and dowsing reactions. Nevertheless, it must be considered as well documented that certain geological anomalies of the underground can be perceived by means of the dowsing technique and that different dowsers reach a degree of agreement which cannot yet be explained by conventional reasoning.