Geophysical methods for the assessment of the ejection of sand due to the liquefaction in the mirabello area

The principal effects of the earthquake (ML 5.9) happened at May 20th, 2012 in Emilia Romagna (Northern region of Italy) were the ruptures and the ejection of sand due to the liquefaction of sand layers present in the subsurface. This study has pointed out the ability of the geophysical high resolution techniques to map the shallow subsurface extent of both fractures and, under certain conditions, the liquefied sand bodies too. In fact while Ground Penetrating Radar investigations detected the fractures in the upper part, seismic reflection profiling gets the possibility to trace back these fractures at greater depths. The results achieved in a test site, a paleo-river bed of the Reno river in Mirabello, permit geologists to obtain proper characterization of the subsurface of the damaged buildings and engineers to aid in formulating appropriate site-specific solutions.