Answer:
Large shallow earthquakes generate the most destructive tsunamis where their epicentre is on a fault line along the ocean floor.
Tectonic subduction and tectonic plate boundaries are the areas most likely to cause tsunamis. Collision of these tectonic plates in these areas of high seismicity cause large earthquakes as the plates move past each other, tilting, offsetting or displacing large areas of ocean floor from just a few kilometres up to 1,000 or more. These abrupt, large, vertical displacements of ocean floor disturb the ocean surface and generate destructive tsunamis as the water is displaced.
The earthquake lifts or lowers the seabed. A tsunami can be generated when the earthquake causes a sudden vertical deformation of the seafloor, thus displacing the overlying water from its equilibrium position. When thrust faults move abruptly a tsunami can be generated when associated with destructive or convergent plate boundaries. This is because of the vertical component of movement and abrupt displacement. Movement on normal faults will also cause displacement of the seafloor but, if the land moves from side to side, not much will happen to the water. Due to the size of such events they are usually too small to generate a large tsunami. On the contrary, if the land moves up or down, it displaces a large body of water. Since water seeks to level itself, this displaced water will attempt to adjust itself in the form of waves.
