Technical Report NTB 87-30
Crosshole InvestigationsShort and Medium Range Seismic Tomography
Seismic tomographic tests were conducted as a part of the Crosshole Investigations program of the Stripa Project. The aim has been to study if it is possible to detect by seismic tomography major fracture zones and determine their dimensions and orientation. The analysis was based on both compressional (P) and transversal (S) waves. The Young's modulus has been also calculated for a sub-set of measurements as a cross check for the P and S wave velocities.
The experimental data was collected at the crosshole site in the Stripa mine during 1984 – 1985. A down-thehole impact source was used together with triaxial detectors and a digital seismograph. Five tomographic sections were obtained. The number of records per section was approx. 250. Measurements were done down to 200 m depth in all boreholes.
The main conclusion of this report is that it is possible to detect major fracture zones by seismic tomography. Their position and orientation can also be estimated.
