Sand volcanoes induced by the April 6th 2009 Mw 6.3 L'Aquila earthquake: a case study from the Fossa area

This paper presents the study of some liquefaction features occurred near the Fossa village due to the April 6, 2009, Mw 6.3 L'Aquila earthquake (Central Italy). Our investigation is based on trenching and coring campaigns as well as sedimentological analyses and datings. The geometrical elements of the sand volcanoes on the surface, of the dike used to rise up and of the probable sandy source at depth are presented. A sandy pockets level found at less than 1 m of depth, interpreted as possible evidence for a paleo-liquefaction event is discussed. Sedimentologic and morphoscopic analyses both provided the necessary elements and parameters to link the ca. 4 m deep sandy layers to the 2009 sand blows on the ground surface as well as to the paleo-liquefaction layer and defined the main characteristics of the deposits sealing the sands that experience liquefaction at depth. Finally a tentative correlation between the paleo-liquefaction layer and the 1461 AD or the 1703 AD local earthquakes is suggested based on the available age constraints.