See Figure 1. The rock holds this new shape. The rock movement pushes and pulls a column of water from the floor to the surface of the sea. See Figure 1. The buckled floor has moved an entire column of water into a trough-first waveform.
Waves emanate from the disturbance just as they do when a rock hits a lake.
The local tsunami travels trough-first. They travel in widening circles across the oceans of Earth for thousands of miles nearly as fast as a jet airliner. When the waves hit the shore, they hit hard with almost all of their initial energy. The wave pattern changes upon reaching shallow waters near the shore. See Figure 2.