In order to make the broadband kinematic rupture modcling more realistic with respect to dynamic modeling. Physical constraints are added to the rupture parameters. To improve the slip velocity function (SVF) modeling, an evolution of the k-2 source model is proposed, which consists to decompose the slip as a sum of sub-events by band of k. This model yields to SVF close to the solution proposed by Kostrov for a crack, while preserving the spectral characteristics of the radiated wavefield, i.e. a ω2 model with spectral amplitudes at high frequency scaled to the coefficient of directivity Cd. To better control the directivity effects, a composite source description is combined with a scaling law defining the extent of the nucleation area for each sub-event. The resulting model allows to reduce the apparent coefficient of directivity ta a fraction of Cd, as weil as ta reproduce the standard deviation of the new empirical attenuation relationships proposed for Japan. To make source models more realistic, a variable rupture velocity in agreement with the physics of the rupture must be considered. The followed approach that is based on an analytical relation between the fracture energy, the slip and the mpture velocity. leads to higher values of the peak ground acceleration in the vicinily of the fault. Finally, to better account for the interaction of the wavefield with the geological medium, a semi-empirical methodology is developed combining a composite source model with empirical Green functions, and is applied ta the Yamaguchi, Mw 5.9 earthquake. The modeled synthetics reproduce satisfactorily weil the observed main characteristics of ground motions.