Seismic Response Spectra of the 24th August 2016 Amatrice Earthquake

The severe seismic events affecting urban areas may have disastrous consequences if buildings are designed without appropriate seismic standards. On 24 August 2016, an earthquake of a magnitude Mw 6.0 caused severe damages, casualties, and collapses in four regions of Central Italy. Due to the high level of observed ground motion and not regular damage distribution, in-depth studies have been conducted on the Amatrice earthquake. In this context, the paper investigates the seismic demand affecting the buildings of the Amatrice during the earthquake focusing on evaluating if the registered seismic actions exceed design spectra. Processing both accelerations acquired by the National Accelerometric Network (RAN) stations and Osservatorio Sismico delle Strutture (OSS) operated by the Italian Dipartimento della Protezione Civile (DPC) and considering available results on site amplification, conclusions on the return period of the seismic event are derived. Moreover, an interpolation method has been introduced to define an Amplification function (Af) to use the information contained in microzoning maps evidencing the enormous amplified elastic demand induced by the peculiar site of Amatrice. Finally, the computed elastic response spectra were compared with the elastic demand spectra provided by the Italian Building Standard (DMIT 2018) in three different manners: (i) taking the response spectra of the registration components directly at AMT and AMTS, (ii) evaluating through realistic de-amplification effects these components at the bedrock, and (iii) considering a realistic average of the two registration AMT and AMTS corrected by possible underestimation errors occurred at AMTS.