The complete characterization of earthquake ground motion includes the length of the interval of strong shaking as well as the amplitude and frequency content of the time series. There are relatively few published equations available for the prediction of strong-motion duration from earthquakes, which may in part be a consequence of the fact that the duration of shaking has generally not been considered in structural engineering. Recognizing that there are many applications for which an estimate of the duration of ground motion is needed, this study presents new empirical predictive equations for a number of definitions of strong-motion duration using the records from the Next Generation of Attenuation (NGA) global database of accelerograms from shallow crustal earthquakes. The equations can be used to estimate ground-motion durations from shallow crustal earthquakes of magnitude between M w 4.8 and 7.9 at distances up to 100 km from the source.

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On April 6, 2009 an earthquake of Magnitude 6.2 (M w ) struck the Abbruzzo region of Italy causing widespread damage to buildings in the city of L'Aquila and surrounding areas. This paper summarizes field observations made by the Earthquake Engineering Field Investigation Team (EEFIT) after the event. The paper presents an overview of seismological and geotechnical aspects of the earthquake as well as a summary of the observed damage to buildings and infrastructure. A brief overview of the earthquake casualties is also reported.

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