Technical Report NTB 87-29

Reflection and Tubewave Analysis of the Seismic Data from the Stripa Cross hole Site

Reflection and tubewave analysis has been made using existing seismic crosshole data. The purpose of the work was to test if crosshole data are suitable for analysis by reflection and tubewave analysis methods.

The data from the crosshole research program (radar, seismics and hydraulics) in the Stripa phase II Project resulted in the construction of a model. The results from the present study were compared to this model.

It was found that the existing data set used for tomographic analysis could only be used to a limited extent, as reflection analysis requires denser detector coverage. Nevertheless two reflectors were detected. The positions of the reflectors were compared to the existing crosshole model and proved to correlate well.

For the tubewave analysis almost all crosshole seismic data could be used. By comparing the results with previous hydraulic tests, it was found that tubewave sources and hydraulically conductive zones are in concordance. All previously defined zones but one could be detected.