BROADBAND SOURCE MODEL FOR THE 2009 L'AQUILA, ITALY, EARTHQUAKE

The 2009 L'Aquila, Italy, earthquake (Mw 6.3) caused severe damage to the city of L'Aquila and tens of villages of the Abruzzo region, killing over 300 people. The mainshock was followed by a significant aftershock activity that extended more than 30 km in northwest-southeast direction. This earthquake provided an unprecedented for a normal faulting event amount of seismological records. During the mainshock, several of the near-fault stations located on the hanging wall of the causative fault experienced ground shakings that exceeded the level prescribed by the design spectra (e.g., Eurocode8) in the period up to 1 s. We studied the source process of the 2009 L'Aquila earthquake in both low- and broadband frequency ranges. The low-frequency (0.05-0.5 Hz) source model was determined by the waveform inversion of the near-field strong motion data, resulting in a slip distribution characterized by an asperity located about 8 km southeast from the hypocenter. The broadband (0.2-10.0 Hz) source characteristics were further determined by employing the empirical Green's function method. Here we discuss the comparison of the derived source characteristics and their influence on the spatial variability of the observed ground motions.