We are living on a geologically active planet. Earthquakes and tsunamis have always been occurring. The largest number of earthquakes occur around the rim of the Pacific Ocean associated with a series of volcanoes and deep-ocean trenches known as the "Ring of Fire".
As a result, the largest source region for tsunamis is in the Pacific Ocean with 71% of all occurrences.
Within the main Pacific Ocean basin, tsunamis generated in the tropics, while locally devastating, tend to weaken rapidly with distance.
However, tsunamis generated in the North Pacific Ocean and along the Pacific Coast of South America often travel throughout the Pacific leaving death and destruction in their wake.
The remaining occurrences of tsunamis happen in the Mediterranean Sea (15%), Caribbean Sea and Atlantic Ocean (7%), Indian Ocean (6%), and finally the Black Sea (1%). Of all tsunamis, 83% are produced directly by earthquakes.
Landslides/rockslides (or icefalls) into water or landslides under the ocean surface can generate sufficient displacement of water to produce tsunamis as well.
One such rockfall occurred on July 9, 1958 in Lituya Bay, Alaska. An earthquake triggered a 40 million cubic yard rock fell at the head of the bay.
Due to the confines of the bay, the resulting tsunami wave reached a height of 1,720 feet (520 meters) on the opposite side of the inlet. Down the inlet itself, the initial wave reached a height of 600 feet (120 meter) moving toward the ocean at 100 mph (160 km/h).
This was not the only time this type of event occurred in this bay. There are at least four other instances of a landslide causing a tsunami in Lituya Bay (1936, 1900, 1874, 1854).
While the magnitude of the 1959 tsunami event has not been matched since it occurred over 50 years ago, 6% of all worldwide tsunamis are generated by earthquake induced landslides.
While also rare, volcanoes can produce devastating tsunamis. One of the most deadliest tsunami events was generated by the Krakatoa volcano eruption in 1883.
|227,899||2004||N. Sumatra||Indian||9.1M Earthquake|
|50,000||1755||Portugal, Lisbon||Atlantic||8.5M Earthquake|
|31,000||1498||Japan, Enshunada Sea||Pacific||8.3M Earthquake|
|27,122||1896||Japan, Sanriku||Pacific||8.3M Earthquake|
|25,000||1868||Chile, Northern||Pacific||8.5M Earthquake|
|18,482||2011||Japan, Honshu Island||Pacific||9.0M Earthquake|
|14,524||1792||Japan, Shimabara Bay, Kyushu Island||Pacific||6.4M Earthquake|
|13,486||1771||Japan, Ryukyu Island||Pacific||7.4M Earthquake|
|8,000||1586||Japan, Ise Bay||Pacific||8.2M Earthquake|
|6,800||1976||Phillippines, Moro Gulf||Pacific||8.0M Earthquake|
|5,233||1703||Japan, Off SW Boso Peninsula||Pacific||8.2M Earthquake|
|5,000||1707||Japan, Nankaido||Pacific||8.4M Earthquake|
|5,000||1687||Puro, South Peru||Pacific||8.5M Earthquake|
|5,000||1611||Japan, Sanriku||Pacific||8.1M Earthquake|
|5,000||1605||Japan, Nankaido||Pacific||7.9M Earthquake|
|5,000||365||Greece, Crete||Mediterranean||8.0M Earthquake|
|4,800||1746||Peru, Lima||Pacific||8.0M Earthquake|
|4,000||1792||Russia, Kamchatka||Pacific||9.0M Earthquake|
|4,000||1792||Pakistan, Makran Coast||Indian||8.0M Earthquake|
|3,022||1933||Japan, Sanriku||Pacific||8.4M Earthquake|
|3,000||1854||Japan, Nankaido||Pacific||8.4M Earthquake|