Joint application of low-cost, fast executable and non-invasive geophysical techniques during emergency and microzonation study: Hints from L'Aquila (Italy) earthquake

A joint application of low-cost, fast executable and non-invasive geophysical methods was applied during the post-event phase following the April 6, 2009 L'Aquila earthquake. In particular, two different types of geophysical surveys were carried out: Electrical Resistivity Tomography (ERT) and Ambient Noise Horizontal-to-Vertical Spectral Ratio (HVSR). More than 200 HVSR and 25 ERT surveys were performed with the aim of characterizing the seismogenic fault system (Paganica San Demetrio Fault System-PSDFS) and to support the seismic microzonation studies in the Aterno river valley. The availability of such large data-base allowed us to evaluate the efficiency of the two geophysical methods when jointly applied. These complementary geophysical methods proved to be useful in detecting the shallow subsurface geological and structural setting, the seismogenic fault system, the geometry of the different lithological units and their mechanical and dynamical properties. In all cases, the results were subsequently supported by data coming from geological field survey, borehole, and strong motion recordings.