Micro Seismic systems are used in the laboratory to study rock fracture phenomena, and to model the behaviour of large-scale real-world seismic systems. Micro Seismic systems use ultrasonic transducers in place of real-world seismic sources and geophones. An ultrasonic transmitter acts as the signal source, and responses are measured via ultrasonic receivers, at sample rates up to around 20 MSa/sec, and for time periods up to around 1ms.
The MIcro Seismic Data Acquisition System automates the collection of micro seismic rock fracture data from an array of 8 ultrasonic receivers and an array of 8 ultrasonic transmitters. Each transmitter is pulsed sequentially in a user-specified order, and 8 ultrasonic receiver responses are captured simultaneously for each transmitter pulse. The receiver responses are acquired at 10 MSa/sec for a user-specified period up to 1 msec. One complete measurement cycle consists of 64 captured signals – 8 signals for each of the 8 transmitters.
Signals can be averaged to reduce noise, and cycles can be repeated according to a user-specified schedule to follow the development of a fracture over time. Data for each measurement cycle is logged to disk as a TDMS file, and the time and frequency profiles for each of the 64 signals in the last recorded cycle are available for viewing while the experiment is in progress.
NI PXI Chassis, PXI Controller and PXI I/O Modules, Femto Amplifiers, Krohn Hite Amplfier.