This presentation will outline numerical simulations of tsunami propagation and field measurements of the evidence left behind by the massive tsunami in 2004 to identify and interpret the factors that have contributed to the significant spatial variability of the level of tsunami impact along the coastal belt of the eastern and southern provinces of Sri Lanka. The model results considered in the present analysis include the distribution of the amplitude of the tsunami and the pattern of wave propagation over the sea bed off the east and south coasts whilst the field data examined comprise the maximum water levels measured at or near the shoreline, the horizontal inundation distances and the number of housing and other buildings damaged. It will be shown that some large-scale features of the ocean bathymetry off the east and south coasts significantly influenced the nearshore transformation of tsunami waves, and consequently, the spatial variation of the tsunami heights approaching the coastline. Such information concerning the spatial distribution of the severity of the tsunami hazard is essential in formulating coastal land use plans, mitigation measures as well as in planning of evacuation of people during tsunami warnings.