How Tsunami Occurs A tsunami typically occurs when there is a sudden movement along faults in the Earth’s lithospheric plates, often due to an undersea earthquake. These plates, which make up the Earth’s outer shell, shift and collide at their boundaries. When stress builds up and is released along a subduction zone—where one lithospheric plate is forced beneath another—this displacement causes a large volume of water to be abruptly pushed upward, generating tsunami waves. These waves travel acr

Video shows eruption that caused tsunami waves