Seismic sources
Weight dropper FFWD-GX II
Free fall of a 360 kg hammer from a height of 4 m with a tool mounted on an IVECO Daily truck.
The tool is equipped with a locking mechanism preventing the rebound of the weight when it hits the base plate.
Under favourable conditions investigation depths of 4500 m have been attained.
Weight dropper BISON EWG III
The fall of a 250 kg steel piston is accelerated by elastic rubber slings. The drop height is 0.8 m. The tool is mounted on a 4×4 GAZ truck.
Under favourable conditions investigation depths of 3000 m have been attained.
Weight dropper VAKIMPAK
The weight is a 50 kg hammer striking upon an anvil in an airtight cylinder. The fall is accelerated by the vacuum produced when the hammer is lifted. The drop height is 1.6m, the total weight is 750 kg.
Under favourable conditions investigation depths of 900 m have been attained.
Weight droppper SAWD
The weight of 15 kg is accelerated by a spring. The SAWD is equipped with a small hydraulic weight lifting unit driven by an electric motor. In order to save battery power the lifting of the weight can be assisted manually. Very handy in rough terrain, the total weight is 150 kg.
Explosives
30 g until 1 kg
Sledgehammers
5 until 12 kg
Shear beam
GeoExperts shear beam for the generation of SH-waves. The 70 kg beam is encased at the ends with steel plates. Beam to ground coupling is improved by several spikes driven into the ground and/or by loading the axle load of vehicle wheels. Using an 8 kg sledge hammer to strike alternately both ends of the beam produces SH-wave trains of opposite polarities, which are used for the identification of the refracted s-wave arrival times.
Seismic recording systems
Smart System by Seismic Instruments
- 18 x 20 channels: 10Hz digital geophones for hybrid seismic surveying
- 6 x 20 channels: 4.5Hz digital geophones for multichannel analysis of surface waves (Rayleigh MASW)
- Central remote unit for data recording using a standard PC
- Seismic Instruments (Austin, USA)
SUMMIT Compact by DMT GmbH & Co. KG
- 10 × 24 channels: 10Hz and 20Hz geophones (24 bit delta sigma technology)
- 4 x 24 channels: shear wave geophones for multichannel analysis of surface waves (Love MASW) and S-waves refraction tomography
- DMT GmbH & Co. KG (Essen, Germany)