To detect seismic signal accurate in the underground geophone anchors were developed at GFZ. This geophone anchors base on real rock anchors used in mining and tunnel construction. Depending on the application the geophone anchors are one to three meters long. The head is composed of three geophones aligned in x-, y- and z-direction to detect the seismic waves spatial. The anchors are screwed into a tubing with a thread insert. Only this tubing is bonded to the rock. Therefore the geophone anchor can be retrieved and reused. The anchors are also licensed to the Herrenknecht AG.