How does a landslide cause a tsunami?

Here is my final version of how does a landslide cause a tsunami?

Landslides that cause tsunamis are called submarine landslides because these landslides take place underwater.

Submarine landslides usually happen in a continental shelf or an underwater trench. Landslides happen here because these areas have large slopes. These areas can have slumping rock, unconsolidated sediment, or weaknesses in the rock areas. Most landslides occur from earthquakes which cause a landslide.

Submarine landslides happen when there is a great mass of land underwater that slides or gets displaced from its original position and falls onto the seabed. The land mass then takes up the space that the water previously had which makes the water rise and make waves.

The size of the waves depends upon the volume of the material moved, the depth pf the submergence and the speed of the landslide. The speed of the landslide depends on how the landslide occurred. Earthquake caused landslides travel very fast because it is a quick break away from the original land mass. Landslides they happen from gradual breakaway travel slower because it is a very slow breakaway.