MONITORING OF TECTONIC STRESS ACCUMULATION IN THE CRUST USING NATURAL AND ARTIFICIAL SEISMIC SOURCES

Abstract

The purpose of this study is to monitor temporal variation in propagation properties of seismic waves, which correspond to crustal deformation in the Tokai region of Japan. There are two approaches that have been studied to investigate the temporal variation of the seismic waves in the Tokai region of Japan. One is a method using a newly developed artificial seismic source named ACROSS, which stands for Accurately Controlled, Routinely Operated Signal System. The work has already been done for the area using this approach. The second approach is a method using ambient noises which are continuously detected by seismometers. This is called seismic interferometry. We can reconstruct Green's function between two seismic stations by calculating cross-correlation of ambient noises between them and thus we can monitor temporal variation of seismic velocity from the continuously calculated Green's functions. In the present dissertation report, I applied this technique of seismic noise interferometry to calculate the long term variation of the perturbation in seismic velocity in the Tokai region of Japan. Finally, the results from both the approaches are compared and discussed.