Peak and integral seismic parameters of L’Aquila 2009 ground motions: observed versus code provision values

Abstract

The M w 6.3 L'Aquila earthquake of April 6, 2009 hit a wide area of the Abruzzo region (Central Italy). The epicentre of the main shock was very close to the urban centre of L'Aquila, the regional capital, with an epicentral distance less than 10 km. It was the strongest earthquake ever recorded in Italy which has provided ground motion recordings from accelerometric stations located in close proximity to the epicentre. Because of this, several remarkable results can be achieved by analysing the strong motion recorded signals in terms of peak (PGA, PGV and PGD) and integral (Housner Intensity, I H ) seismic parameters. Additionally, an alternative time-domain representation of recorded signals has been used to furnish a rapid comparison of traces recorded at different stations and along different directions. Some comparisons between the response spectra derived from the recordings and the elastic demand spectra provided in the new seismic Italian code have also been performed. PGA recorded values are very high and generally higher than code values for seismic actions with return period T R = 475 years. In some cases, this also happens for seismic actions with T R up to 2,475 years. With regard to I H , recorded values are generally higher for T R = 475 years, whilst they are remarkably lower for T R = 2,475 years. Accurate analyses have been carried out in the article to better understand the above differences and their significance and implications.

Frequency variation in site response as observed from strong motion data of the L’Aquila (2009) seismic sequence

“…The main information about the selected events is reported in Table 4. According to the spectral analyses shown in the previous sections, we rotated the accelerometric time series in the horizontal plane to obtain the maximum PGA In order to synthesize the results, we report only the parameters recorded along the direction for which the I H is maximum, being I H a parameter better correlated to the energy content of an earthquake rather than PGA to analyze the response of soils and buildings (see e.g., Masi et al 2010). It is worth noting that while the maximum PGA value was recorded at AQV during the mainshock, the M = 5.6 aftershock recorded at MI05 has a PGA larger than the mainshock at the remaining RAN stations.…”

The Role of Site Effects at the Boundary Between Seismology and Engineering: Lessons from Recent Earthquakes

“…For l'Aquila event, the difference between the observed recordings and code provision was mainly due to the choice of parameters used rather than in a bias in base hazard estimates or insufficient description of site effects . After correcting for soil class according with Vs30, Masi et al (2011) showed that Housner Intensity provided much better results than PGA (Fig. 5.6), and was well correlated with site seismic hazard obtained from the long series of macroseismic data available.…”

Seismic hazard from instrumentally recorded, historical and simulated earthquakes: Application to the Tibet–Himalayan region

“…For validation or confirmation of PSHA using observed ground-motion records, a control period of consecutive observations is necessary (e.g., Albarello and D'Amico, 2008;Beauval et al, 2008;Miyazawa and Mori, 2009;Stirling and Gerstenberger, 2010;Mezcua et al, 2013; see also a review in Stein et al, 2012, anddiscussion in Iervolino, 2013). However, the direct comparison of ground-motion records obtained during a single earthquake with the probabilistic seismic hazard model allows analyzing the consistency of the model and the observations available (e.g., Crowley et al, 2010;Masi et al, 2011;Meletti et al, 2012;Sokolov et al, 2004). The comparison may result not only in compilation of new hazard maps and consequently in new seismic Fig.…”