High-rate GNSS techniques for the detection of large seismic displacements

Measurement of co-seismic strong-motion displacements at sub-second temporal resolution is of great importance for earthquake studies. We have investigated the usage of high-rate sampled Global Navigation Satellite System (GNSS) data to measure seismic motion by implementing an industrial robot simulating the displacements close to an earthquake epicenter. The robot arm is tracked by GNSS signals. Two baselines-400 m and 60 km-from the robot to reference stations are used to process the observed GPS data. Both methods give similar (within 0.5 mm) Root Mean Square (RMS) differences between the estimated and the commanded coordinates. The RMS differences are 3.5 mm in the east component, 5.6 mm in the north component, and 8.1 mm in the vertical component.