The L’Aquila 2009 earthquake: an application of the European Macroseismic Scale to the damage survey in the epicentral area

Abstract

On April 6, 2009 a Mw 6.3 earthquake heavily damaged the city of L'Aquila, its suburbs and several localities along the Aterno valley. The extent of the damage was the result of several factors, among which the high vulnerability of the ancient buildings but in some cases also of the modern ones, the structure of the urban centres and the site effects deriving from local critical geological conditions. We present the results of the macroseismic investigation carried out in the epicentral area by using the European Macroseismic Scale (EMS), a more suitable scale than the Mercalli-Cancani-Sieberg (MCS) one in evaluating rather complex damage scenarios. The maximum intensity has been estimated for Onna (IX EMS), the historical centre of L’Aquila, and for Castelnuovo, Pettino and S. Elia (VIII-IX EMS). On the whole, some 30 localities within an area that extends for 35 km in a NW-SE direction suffered significant damage (VII-VIII EMS). Finally, we discuss the differences in the intensity assessment deriving from the interpretation of the MCS and EMS scales.