[SSS14-P24] Rupture Process of the M5.5 Orkney Earthquake Using Strainmeters at Very Close Distance
Keywords:South Africa, inversion, Close, induced earthquake, strain meter
We try to model rupture process of the M5.5 mainshock using the nearfield strainmeters and surface strong motion meters data using a multi-time window method (Yoshida et al. (1996)). For the analysis, we used a horizontal stratified structures obtained by H. Ogasawara (2018 Msc) and A. Mangongolo (2014). The strain Green functions that include near-field terms and static off-sets were calculated using a finite difference method. Since the absolute timing of the strainmeters is not accurate, we decided set the starting point of rupture using a hypocenter determined by data from the 17 surface strong motion meters.
As a result of the analysis, large slip on the fault occurred in the northern region and the rupture propagated bilaterally upwards to the north and downwards to the south. This result is consistent with the absence of observed faulting in the mine tunnels and the inclination of aftershock distribution from north to south.