Siren is a site response analysis program that calculates the soil response, attributable to specified movement in the bedrock. This is achieved by modelling the soil as a non-linear one dimensional soil column with an earthquake motion input at its base.
Properties are assigned to the bedrock and the soil is modelled as a non-linear stress-strain curve which incorporates hysteresis effects. Excitation is assumed to apply at the bedrock level and an explicit time integration scheme is used to calculate the soil response with time.