How Tsunamis Form from Earthquakes, Volcanoes, and Landslides
John Rafferty, associate editor of Earth sciences at Encyclopædia Britannica, discusses the formation of tsunamis.
Encyclopædia Britannica, Inc.
-
Contunico © ZDF Studios GmbH, MainzLearn about Eurasian beavers.
-
© MinuteEarth (A Britannica Publishing Partner)The role of the Rocky Mountain locust (Melanoplus spretus) in the Grasshopper Plague of 1874–75 (which is also known as the Great North American Locust Plague), and the insect's mysterious disappearance that followed.
-
Created and produced by QA International. © QA International, 2010. All rights reserved. www.qa-international.comThe big-bang theory proposes that the universe expanded from a highly compressed state.
-
Encyclopædia Britannica, Inc.The eruption of Paricutín lasted for nine years and produced one of the world's youngest volcanoes. Ash and lava began spewing from an open field in 1943 in Michoacán state, Mexico, and buried nearby settlements and farmland and displaced local people. The result was a new cinder cone volcano. This video, produced in the 1970s, includes footage taken during the eruption.
-
Encyclopædia Britannica, Inc.Lava flowing toward the sea from Kilauea volcano, Hawaii, takes two recognizable forms: fast-flowing ropy lava called pahoehoe and thick blocky lava called aa.
-
Encyclopædia Britannica, Inc.Learn about the ancient Roman city of Pompeii, which was buried in volcanic ash when Mount Vesuvius erupted in 79 ce.
-
Encyclopædia Britannica, Inc.Learn about the different kinds of volcanic eruptions.
News •
Strong earthquake shakes central Japan, shattering store windows and injuring at least 22
• Nov. 8, 2026, 2:23 AM ET (AP)
Medieval Humans Partly Caused Two Catastrophic Lake Tsunamis, And We Could Easily Do It Again, Scientists Warn
• Nov. 3, 2026, 8:02 PM ET (ScienceAlert)
Rescuers search for survivors after deadly earthquake in China’s Tibet region
• Oct. 23, 2026, 5:51 PM ET (AP)
Powerful earthquake in China’s Tibet region collapses hundreds of homes and kills at least 16 people
• Oct. 23, 2026, 1:25 AM ET (AP)
Transcript
The tsunamis that we're most familiar with are caused by underwater earthquakes, volcanoes, or landslides. A part of the crust falls away or is suddenly thrust upward and that displaces the water. Very similar to if you would throw a rock into a calm lake. So that rebounding effect is going to create waves that move out in all directions. Now, the deeper the water the less you're going to see that wave at the surface, until that wave reaches the--reaches the shoreline.
Large tsunamis can approach 30 meters, or 100 feet, in height, and they can push inland up to several miles. There are smaller ones that cause very little damage or no damage because the--the run-up onto the shore is just not that significant.
Large tsunamis can approach 30 meters, or 100 feet, in height, and they can push inland up to several miles. There are smaller ones that cause very little damage or no damage because the--the run-up onto the shore is just not that significant.
Last Modification: