What is the difference between a GTSM Strain Meter and a Seismometer?
The GTSM Strain meters are continuously measuring the changes in borehole shape (deformation) regardless of the rate of change. Seismometers typically have a weight suspended on a spring. When a seismic wave moves through the instrument, the weight moves relative to the instrument and the output signal is proportional to the velocity of the particles in the rock. For this reason, seismometers are excellent at recording high frequency earthquake data. Strain meters can also measure these waves, but do so by directly measuring the change of position of the borehole wall. This deformation can be very slow for many earth signals, such as the strain on the earth resulting from lunar and solar tides or from slow earthquakes. This is where the GTSM strain meter has a definite advantage.
