The Source, Path and Site Effects for ML 6.0, 2016 Amatrice Earthquakes

Abstract

The strong ground motions recorded by Italian Strong Motion Network (RAN) in ML 6.0 2016 Amatrice earthquake and 42 aftershocks (4.0≤M≤6.5) at 65 stations are used to analyze the source spectra, seismic path attenuation, and site effects using the generalized inversion techniques (GIT). Ground motion with PGA greater than 2 gal are chosen, and each station recorded at least 20 earthquakes, and there are at least 18 station recording ground motions in each earthquake. Using the GIT, the source spectra and site amplification effect are separated from the Fourier spectra of observed 1840 sets of ground motion records. The larger earthquakes have similar source spectra with peaks at 1.0 Hz and 3.0 Hz. The smaller earthquakes also have similar source spectra with higher frequency or corner frequency at 10.0 Hz. The site effects at most sites are larger than 1 meaning the sites are soil condition. The peaks at station GUMA is around 1 Hz, and station NRC, NCR and AMT have relatively stiffer soil condition with peaks at around 4-10 Hz.