GEOTECHNICAL AND GEOPHYSICAL DESCRIPTION OF EURO-SEISTEST, USING FIELD, LABORATORY TESTS AND MODERATE STRONG MOTION RECORDINGS

EURO-SEISTEST is a European test site established in the Mygdonian basin, near Thessaloniki, in Northern Greece. Its aim is to allow detailed and well documented studies in many fields of engineering seismology, earthquake engineering, soil dynamics and seismology. Theoretical and experimental seismic ground response analysis along the valley is one of the most important tasks of the project. The very detailed knowledge of the geological and geotechnical structure of the site as well as numerous data from a continuous seismological and geodetical survey and dense semi-permanent and permanent instrumentation, offer the possibility of conducting detailed empirical and theoretical studies on the effects of surface geology on seismic ground motion. EURO-SEISTEST is a unique test site for checking the reliability of existing theoretical models of site effects, to develop new ones, and to interpret the physics of seismic ground response. The paper presents: (a) the general layout of the test site, (b) the main results of the extensive geophysical and geotechnical surveys, to determining the geometry and the dynamic properties of soil formations, and (c) the validation of valley's structure with instrumental estimates of the site effects along the valley. Emphasis is given to comparisons and correlations between results derived from different methods of seismic prospection (refraction, surface wave inversion, borehole seismics) and geotechnical in situ tests. In order to better constrain the structure of the valley and the dynamic properties of the soil formations, specific criteria and procedures are developed for soil characterisation.