Submarine earthquake
Date Event Location Estimated moment magnitude ( M w )
March 11 , 2011 2011 Tōhoku earthquake The epicenter is 130 kilometers ( 81 mi ) off the east coast of the Oshika Peninsula , Tōhoku , with the hypocenter at a depth of 32 km ( 20 mi ) 9.1
December 26 , 2006 2006 Hengchun earthquakes The epicenter is off the southwest coast of Taiwan , in the Luzon Strait , which connects the South China Sea with the Philippine Sea 7.1
December 26 , 2004 2004 Indian Ocean earthquake The epicenter is off the northwestern coast of Sumatra , Indonesia 9.1
May 4 , 1998 A part of the island of Yonaguni was destroyed by a submarine earthquake
May 22 , 1960 1960 Valdivia earthquake The epicenter is off the coast of South Central Chile 9.5
December 20 , 1946 1946 Nankaido earthquake The epicenter is off the southern coast of Kii Peninsula and Shikoku , Japan 8.1
December 7 , 1944 1944 Tōnankai earthquake The epicenter is about 20 km off the coast of the Shima Peninsula in Japan 8.0
November 18 , 1929 1929 Grand Banks earthquake The epicenter is at Grand Banks , off the south coast of Newfoundland in the Atlantic Ocean 7.2
June 15 , 1896 1896 Sanriku earthquake The epicenter is off the Sanriku coast of northeastern Honshū , Japan 8.5
April 4 , 1771 The epicenter is near Yaeyama Islands in Okinawa , Japan 7.4
January 26 , 1700 1700 Cascadia earthquake The epicenter is offshore from Vancouver Island to northern California ~9.0
List of major submarine earthquakes
The following is a list of major submarine earthquakes since the 17th century .
A submarine, undersea, or underwater earthquake is an earthquake that occurs underwater at the bottom of a body of water, especially an ocean. They are the leading cause of tsunamis. The magnitude can be measured scientifically by the use of the moment magnitude scale and the intensity can be assigned using the Mercalli intensity scale. Understanding plate tectonics helps to explain the cause of submarine earthquakes. The Earth's surface or lithosphere comprises tectonic plates which average approximately 50 miles in thickness, and are continuously moving very slowly upon a bed of magma in the asthenosphere and inner mantle. The plates converge upon one another, and one subducts below the other, or, where there is only shear stress, move horizontally past each other (see transform plate boundary below). Little movements called fault creep are minor and not measurable. The plates meet with each other, and if rough spots cause the movement to stop at the edges, the motion of the plates continue. When the rough spots can no longer hold, the sudden release of the built-up motion releases, and the sudden movement under the sea floor causes a submarine earthquake. This area of slippage both horizontally and vertically is called the epicenter, and has the highest magnitude, and causes the greatest damage. As with a continental earthquake the severity of the damage is not often caused by the earthquake at the rift zone, but rather by events which are triggered by the earthquake. Where a continental earthquake will cause damage and loss of life on land from fires, damaged structures, and flying objects; a submarine earthquake alters the seabed, resulting in a series of waves, and depending on the length and magnitude of the earthquake, tsunami, which bear down on coastal cities causing property damage and loss of life.