- from Earthquakes
Earthquake waves go through water as well as land.
When the waves hit the shore, they often do more damage than the quake alone.
Volcanoes can erupt when earthquakes hit. It happens more often under the ocean than on land. Deep trenches form on the seafloor when one plate is forced under another, causing an earthquake. Some of the hot liquid rock below Earth’s crust gets pushed out, and an eruption takes place.
When one plate is forced underneath another, the process is called subduction. Some of the Earth’s crust is pulled into the mantle. Some of the soft, hot rock in the mantle is pushed up and becomes new crust.