Microtremor measurements is an efficient alternative method, which will be used for detecting both stratigraphy in terms of the stiffness (detailed Vs profile) and resonant frequency. Special temporary arrays of broadband instruments will be installed at different locations in the test site area to record permanent ambient noise and to analyse it. Both results (stratigraphy-stiffness and resonant frequency) will be compared with results from seismic prospecting and transfer functions from earthquakes as well as from more conventional geotechnical data (borehole lodging, in-situ and laboratory tests). Refined study will be also performed in order to approach the wavefield of microtremor and consequently the validity of the horizontal to vertical component (H/V) method in site effects studies (estimation of the predominant frequency).