Non-linear Ground Motion Simulation at the Sites of Atalanti Gulf Area for the Case of Real and Hypothetical Earthquakes

We perform numerical simulation of the ground motion and liquefaction at several sites located at the coastal area of Atalanti Gulf (Greece). To incorporate region-specific geologic effects in the ground motion and liquefaction hazard estimates, subsurface information, particularly Vs and dynamic properties, are compiled and evaluated with the aid of geophysical methodologies and borehole testing respectively. The possible non-linear soil behavior at the investigated sites is examined for three selected earthquakes. In two cases, real records, obtained from the NOA database, are used as input motion. In third case the input motion is computed using a stochastic simulation technique, for the scenario earthquake of the 1894 Atalanti main shock with M=7.0. The results of the modelling show that in the case of an earthquake with magnitude Mw=5.4 all sites amplify the input signal to some degree. In case of Mw=6.7 earthquake almost all investigated sites will exhibit liquefaction initiation. An exception is two sites: one, where strong amplification of input motion by the shallow soft layers is expected; another one, located very close to the eastern segment of Atalanti fault, where obtained surface motion is not significantly changed through the structure. The Atalanti earthquake produces both effects liquefaction and amplification.