In order to provide more insight into land propagation of T phases, signal analysis of these phases recorded inland has been carried out. We found that the wave train is composed mainly of Pg and Sq waves which reach the seismic station from different azimuths. With the hypothesis that the signal is the sum of discrete arrivals due to different rays crossing the continental slope at different locations, synthetic seismograms of T waves are computed taking into account the variation of the conversion point along the slope. The transmission of energy from the ocean to the continental crust is mainly due to diffraction effects. The duration and the amplitude of the T phase, which are two criteria used to evaluate tsunami risk, are greatly influenced by the shape of the continental slope.