Earthquake waves go through water, too, not just land.
When the waves hit the shore, they often make the damage much worse.
Volcanoes can erupt when earthquakes hit. That happens under the ocean more than on land. When one plate is pushed under another, an earthquake happens. Also, deep trenches form on the seafloor. Some of the hot rock below the Earth’s crust gets forced out. That’s when an eruption takes place.
Subduction happens when one plate is pushed under another. Some of the Earth’s crust gets pulled into the mantle. Also, some of the soft, hot rock in the mantle gets pushed up. That stuff turns into new crust.
