How do tsunamis form and how is this different from volcanoes?

Underwater earthquakes cause the sea floor to move violently . Undersea volcanoes cause explosions under the water . Both of these events create huge waves that spread across the surface of the ocean . Tsunamis speed outward away from their source in all directions Most tsunamis are caused by earthquakes on converging tectonic plate boundaries. ... However, tsunamis can also be caused by landslides, volcanic activity, certain types of weather, and—possibly—near-earth objects (e.g., asteroids, comets) colliding with or exploding above the ocean.