[SSS14-10] Plate coupling variation of the Nankai trough megathrust zone revealed by GNSS-A observation
Recently, Yokota & Ishikawa (2020) analyzed GNSS-A data up to 2018 statistically and revealed the existence of slow slip around the shallow side of strong coupling regions estimated by Nishimura et al. (2018). However, the crustal velocities used to estimate the plate coupling is mean values without considering transient variation such as slow slip. Because the mean velocity of the site including the slow slip period becomes slower, it is trivial that the slow slip area overlaps with the weakly fixed area.
To investigate the relationship between the slow slip area and the strong coupling region more properly, it is necessary to estimate start and end time of slow slip events accurately. With the current ability of GNSS-A observation, this is difficult task because of the fewness of the observation frequency and the shortness of the observation period. In this presentation, we report how accurate the temporal variation of velocity field and plate coupling can be detected.