Abstract:
For investigating the rupture directivity effect of the central Italy
MW6.2 earthquake on August 24, 2016, more than 150 strong motion stations are separated into two groups, which are SE and NW, according to the fault strike. Comparing the PGA, PGV, pseudo-acceleration response spectrum (PSA) and significant duration
DSR of two groups, the results show that: the observed PGAs, PGVs and PSAs of NW group are larger than those of SE group; the residuals between the observed and predicted PGAs and PGVs are significantly correlated with the azimuth; the observed
DSR of NW group is smaller than that of SE group. From these observations we deduce that the rupture directivity effect exists in this earthquake. Furthermore, the inversion for source rupture parameters using PGAs and PGVs, respectively, shows that the rupture is bilateral, and the
MW6.2 earthquake predominantly ruptured in the direction 345°--360°, accounting for 70%--80% of the total rupture, and the rupture velocity is 2.2--2.5 km/s. These results validate the conclusion that the differences of ground motion parameters between two groups of stations might be caused by the rupture directivity effect.