How GPS seismology become possible

Speaker: Jiun Ting Lin

Date: 2013/11/28

Abstract

       Application of the high-rate GPS become popular for the seismology used. Unlike other instruments, for example, accelerometer is difficult to convert the acceleration measurements unambiguously to displacement. These problems are compounded for long periods or when the accelerometer experiences strong or permanent displacements. Broadband seismometer is more sensitivity and have better resolution for the ground motion, but may clip during the strong motion. However GPS provides truly displacements and unsaturated measurements, even in the permanent offsets and the kinematic ground motion.
        Recently an increasing number of continuously GPS receivers are operating at seismic frequencies. In order to apply GPS to the seismology used, it is important to reduce systematic errors, such as the multipath effect. By applying aspect repeat time adjustment (ARTA) method, most of the multipath effect error may be eliminated.
      On the other hand, time resolution is also an important information for the capability of capture dynamic ground motion. Modern receiver technology now enables sampling of GPS observations at very high sampling rates of 10 to 50 Hz. However, the higher sampling rate does not necessarily mean higher corresponding observations. The dynamic characteristics of the high rate observations will be limited by the bandwidth of the signal tracking loops. An ideal testing environment is trying to find out the dynamic range of the different instruments.
      Both of the environment noise and the dynamic response of the instrument distorted the GPS signal. It is important to correct the signal to real ground observations, in order to apply the GPS signal to the seismology used.

References

Ebinuma, T., & Kato, T. (2012). Dynamic characteristics of very-high-rate GPS observations for seismology. Earth, planets and space, 64(5), 369-377.

Larson, K. M., Bilich, A., & Axelrad, P. (2007). Improving the precision of high‐rate GPS. Journal of Geophysical Research: Solid Earth (1978–2012), 112(B5).