This study presents a preliminary calibration of a large-scale seismological model of the M W 6.6 Niigata-Ken Chuetsu-Oki (Japan) earthquake of July, 16 th 2007. The strong ground motion affected a wide area in the surrounding of the Kashiwazaki-Kariwa Nuclear Power Plant (KKNPP). Due to the relative small source-to-site distance and shallow hypocenter depth, this seismic scenario resulted very interesting and well documented (a consistent database of seismic recordings is available). In this context, the test-case represents a suitable benchmark for the work-packages of the SINAPS@ project. SINAPS@ is the first French research project with the objective to quantify the uncertainty of the procedures to estimate the seismic risk. In this context, an omni-comprehensive approach is followed, modelling the wave-propagation from the fault to the structural components. This study is intended to describe the steps to build up and calibrate a reliable seismic scenario, capable to provide a synthetic wave-field at the regional scale. This objective is pursued by (1) assessing a stratified geological model for the Niigata region, (2) testing the effect of the source parameters in a kinematic approach (e.g. the rise time and the shape of the Source Time Function) and (3) checking the topography effect. A series of 3D source-to-site numerical simulations of the M W 4.4 NCOEQ2007 aftershock was therefore carried out with this regard (performed by means of the Spectral Element Method, SEM). The seismic scenario was calibrated with the aid of the semi-analytical solution provided by the Wave-Number Integration Method (WNI) and by comparing the synthetics with the recordings at several locations (i.e. the KNET-Kik-Net stations nearby and the KKNPP site). Finally, the forward physics-based analysis ended up by providing broad-band synthetic time-histories to be exploited in further studies as a reliable regional incident wave-field for the engineering bedrock