In current design practice, geotechnical earthquake engineers are often responsible for providing the appropriate design ground motions for structural analysis, studying the effects of earthquakes and elaborating methods to mitigate these effects. A site response analysis is required to investigate the complex interaction between the seismic waves and the local site conditions. Morphology, stratigraphy, water conditions and soil properties have a high influence not only on the characteristics of the earthquake (for example in terms of duration, peak acceleration and frequency content) but also on the modelling strategy.