Slope dynamic response to earthquakes: Insight from the 2009 L’Aquila earthquake

Long term accelerometric monitoring of a tectonically and geomorphologically active site in Central Italy (Caramanico Terme) is used to study the dynamic response of slopes to seismic shaking. By combining the 2009 Mw 6.3 L’Aquila earthquake data with results based on lower magnitude events recorded earlier, it is shown that a valuable assessment of site response properties can be obtained by averaging weak motion data, provided the latter are sufficiently dif-ferentiated in terms of azimuth location, distance, energy and source characteristics. The case of directional amplification affecting a slope prone to deep-seated landsliding is described to offer some practical indications on how to estimate the presence and significance of site effects on slopes susceptible to seismic failures. For the monitored slope we estimate that amplifications of shaking energy, expressed through Arias intensity, vary on average from 2 to 16, if calculated relatively to sites on soft soil or rock, respectively