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Spectral Analysis of Surface Waves (SASW) / Multichannel Analysis of Surface Waves (MASW)

The Geotechnical Laboratory has equipment to perform Spectral Analysis of Surface Waves (SASW) and Multichannel Analysis of Surface Waves (MASW). The SASW/MASW tests are used to develop shear wave velocity profiles in situ. The test setup comprises a Geode Seismograph, a Zero db preamp gain, a striker plate, a hammer, software to record and analyze the data, and cables manufactured by Geometrics, and 24 rotating coal GS-11D geophones manufactured by Geospace Technologies.

The Geode Seismograph is a small, lightweight, versatile, and flexible seismograph. The Geode seismic modules has 24 channels, weighs only 8 lbs, and interconnects using inexpensive digital network cable. The Geode will run all day on a small 12v battery and sleeps when not in use.

Geode architecture and Geometrics software lets you build seismic recording systems from 3 to 1000 channels with multiple lines and built-in roll capability. The low power Geodes even have an on-board hardware correlator that can be used for swept sources and MiniSosie (pseudo-random) surveys and compress data before transmission.

For light-duty applications, you can run the Geode from your laptop to view, record, and process your data. The software interfaces to the Geode as a simple high-speed network device, eliminating the need for special drivers and cards.

Place a Geode module out on the line close to the geophones or well head and eliminate long, expensive analog cables. Never hassle with poor connections and bad roll box contacts when doing a reflection survey. And when you are not using the Geode for exploring, use it for monitoring earthquakes, quarry blasts or vibration from heavy equipment.

The GS-11D is a high output, rotating coil geophone designed and built to withstand the shocks of rough handling. The precision springs of this field proven geophone are computer designed and matched to optimize performance specifications even under the most extreme conditions.

Gold plated contacts assure positive electrical connections. The Geo Space manufacturing process includes checking all geophone operating parameters with the ATS, an automated computerized test system.

Natural frequencies are 4.5, 8, 10 and 14 Hz, with standard coil resistance of 380 ohms. The PC-21 Land Case is used with the GS-11D geophone.

For more information about the Geode Seismograph please click here

For more information about the Geospace G-11D Geophones please click here