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DEPARTMENT OF THE NAVY -- NAVAL HISTORY AND HERITAGE COMMAND

Tsunami (Tidal Wave) Disasters and the U.S. Navy

Related Resources:

Injury and Destruction of Vessels by Earthquakes, Report of the Secretary of the Navy, December 1868
Reports of USS Powhatan and USS Wateree, 1868
<Vessels Lost and Salvaged, Report of the Secretary of the Navy, 1916
U.S. Navy Relief Efforts after the Indian Ocean Tsunami, 26 December 2004
A Sampling of U.S. Naval Humanitarian Operations by Adam Siegel


In contrast to   These waves can reach 90 feet (30 m) in height and the larger tsunamis have caused great destruction and loss of life across entire ocean basins.

The word tsunami is composed of the Japanese words "tsu" (which means harbor) and "nami" (which means wave).  The term "tidal wave" was often erroneously used to describe the same phenomenon, particularly because of the sudden tide-like retreat of water from the coast as the tsunami wave closed the shore.  But tsunami waves are not the same as astronomical tide waves, nor are they caused by the normal gravitational influences of the moon, sun, and the planets.  Thus, the Japanese word tsunami or “harbor wave” is a more inclusive term and has been internationally adopted because it covers all forms of impulse wave generation.

By far, the most destructive tsunamis are generated from large, shallow earthquakes with an epicenter or fault line near or on the ocean floor.  These usually occur in regions of the earth along active tectonic plate boundaries, particularly along the Pacific Ocean's “Ring of Fire” – a circle of active tectonic plate boundaries stretching from Indonesia to Japan, to the Aleutian Islands, to the west coast of North America and south all the way to Chile – but also in the Atlantic and Indian Oceans as well.  Not all earthquakes generate tsunamis, since it usually takes an earthquake with a Richter magnitude exceeding 7.5 to produce a destructive tsunami.  On 26 December 2004 a megathrust earthquake (9.0 Richter scale) occurred along the India-Burma plates was such an event, in which an estimated 750 miles (1,200 km) of fault line slipped 60 feet (20 m) and vertically raised the Burma plate a few meters.  The resulting shockwave caused massive waves that killed an estimated 160,000 people in Indonesia, Thailand, India, Sri Lanka, the Maldives, and other locations in the Indian Ocean basin, making it the most lethal tsunami in recorded history.

The first historical reference to a tsunami is the 15th century B.C. volcanic explosion of Thera [Santorini] Island in the Greek archipelago, which produced a massive wave that caused widespread damage on Crete and other Aegean Islands.  This event may have contributed to the decline of Minoan civilization and is most likely the source of Plato's parable of Atlantis.  Japanese records report multiple tsunamis over the last two millenia, with tens of thousands of people killed.  A quake and tsunami in England's Bristol Channel in 1609 destroyed whole villages on both shores, killing thousands.  Following an earthquake under the Iberian peninsula in 1755, perhaps 90,000 people died in Lisbon, Portugal, from quake damage, fires and a tsunami that killed survivors clustered on shore.  In 1883, the island volcano of Krakatoa in the Sunda Strait exploded, sending huge tsunami waves crashing into Java and Sumatra and killing over 36,000 people.

The Navy's experience with damaging tsunamis was rare at first, partly owing to the small size of the early sailing navy and the low frequency of large tsunami-producing earthquakes.  On 18 November 1867, however, a magnitude 7.5 earthquake occurred in the harbor of St. Thomas, swept the side-wheel steamer DeSoto from her moorings, snapping both chains, and throwing the ship into the iron pilings of a new wharf.  Fortunately, the next wave lifted the ship off the wharf and carried her back to deep water with only minor damage.  The side-wheel steamer Susquehanna, in the same harbor, escaped without damage.  Less fortunate was the screw sloop-of-war Monongahela, which was anchored off Frederickstadt, St. Croix.  A massive wave lifted the ship over the warehouses along the shore and into one of the streets of the town.  The ship came back with the returning sea and was left on a reef at the water's edge, with five of her crew lost.  Recovery efforts eventually refloated the screw sloop on 10 May 1868.

A short time later, an 8.5 magnitude quake struck northern Chile on 13 August 1868, killing over 25,000 people.  At the port of Arica, the storeship Fredonia and the steam gunboat Watereefelt the shock of the quake and soon thereafter found themselves sitting on the harbor bottom amidst flopping fish when the sea receded as part of the tsunami wave surge.  The tsunami hit moments later, breaking Fredonia into pieces and killing 27 members of her crew, leaving only 5 survivors.  The wave also carried Wateree 500 yards above the high water mark, but only one sailor from the gunboat was drowned.  As refloating and repairing Wateree would have been impossibly expensive, the gunboat was sold where she lay in November 1868 and her hulk was later reportedly used as an inn.  In an early example of what is now called humanitarian relief operations, two other ships of the South Pacific Squadron, the side-wheel steamer Powhatan and the screw sloop Tuscarora, carried surgeons, nurses and supplies from Calao and Valparaiso to Arica and other stricken locations along the coast.

Another ship loss took place on 29 August 1916, when successive tsunami-like waves rolled into the harbor of San Domingo City, Dominican Republic.  The armored cruiser Memphis (formerly the U.S.S Tennessee) was wrenched from her anchorage and lifted toward shore, repeatedly slamming into the harbor bottom.  The cruiser eventually came to rest only 40 feet from the shoreline.  Three sailors were washed overboard and drowned; seven were killed from burst steam pipes in the cruiser; and thirty men drowned after their small boats capsized in the waves.


  The 20th century saw thirteen Pacific-wide tsunamis, all of which swept across the entire basin, reflected off distant shores, and set the entire ocean in motion.  One of the most destructive of these tsunamis was generated by a 7.8 magnitude earthquake near Unimak Island in the Aleutian Islands on 1 April 1946.  A huge wave over 100 feet high (35 m) completely overwhelmed the U.S. Coast Guard's Scotch Cap lighthouse on Unimak, destroying the steel-reinforced concrete building and crushing all five crewmen.  Five hours later, heavy waves slammed into Hilo Bay on the island of Hawaii, destroying the waterfront there as well as at Laupahoe Point, and killing 165 people.


Pacific Tsunami Warning Center in Hawaii.  The center was designed to collect earthquake sensor data and quickly promulgate tsunami warnings, allowing the timely evacuation of coastal settlements in response to distant seismic events.



On 22 May 1960, a magnitude 8.6 earthquake took place off the coast of south central Chile, killing 2,300 people.  The resulting Pacific-wide tsunami struck the Hawaiian Islands, parts of Japan, and elsewhere.  Hilo was again severely damaged, with waterfront buildings destroyed and 61 people killed.  In response to the widespread damage in Chile, the dock landing ship Catamount (LSD 7) departed San Francisco, Calif., on 23 June with a cargo of 12 landing craft and spare parts.  The ship arrived in Valparaiso on 11 July.  Embarking Chilean sailors to man the landing craft, Catamount fueled and got underway that same night for Talcahuano to deliver engine spares on the next day.   The dock landing ship proceeded south to Puerto Montt on 14 July, where the landing craft were used to ferry supplies ashore, all the wharves having been destroyed by the tsunami.  Catamount's crew trained Chilean boat crews until 17 July before the ship sailed for home.


A third huge Alaskan earthquake took place on 28 March 1964 when a magnitude 8.4 event shook a 500 by 100 mile area extending from Valdez to the Trinity Islands southwest of Kodiak Island.  Vertical crust displacement averaged six feet, producing destructive tsunamis in Alaska, British Columbia, California, and Hawaii, which killed 120 people.  Alaska's fishing industry and many seaports were heavily damaged, as were ports stretching from Vancouver, B.C., south to California, with Crescent City hit especially hard.  The Kodiak Island waterfront was also struck by waves which washed away 158 houses and carried fishing boats hundreds of meters inland.  In response, Navy P-3A Orion patrol aircraft and C-54 Skymaster cargo planes flew emergency supplies up from Moffett Field.  The seaplane tender Salisbury Sound (AV 13) also got underway from NAS Whidbey Island, Washington, and arrived at Naval Station Kodiak on 31 March.  The tender linked her electrical generators to the naval station's power lines, provided clean water for residents, took care of laundry and meal services, and offered hot showers and warm bunks for workers who had previously been sleeping in unheated barracks.  Working parties from the ship helped fix the power plant, repaired the airfield radar system, and joined in the general cleanup operation until departing on 10 April.


The 1960 and 1964 efforts by the Navy to help tsunami victims illustrate the more general practice of seafarers providing humanitarian assistance to victims of storms, shipwrecks and other maritime disasters.  Although the practice of government-sponsored rescue efforts did not become widespread until the 19th century, when public and private lifesaving organizations developed coastal rescue services, navies the world over have a long tradition of helping disaster victims.  For example, at the same time Catamount was preparing to sail for Chile in 1960, seven helicopters from Helicopter Antisubmarine Squadron 4 from the aircraft carrier Yorktown (CVS 10) rescued 53 merchant seamen from the British freighter Shun Lee which was breaking up on Pratas Reef, 500 miles north of Manila, Philippines.


Other Navy humanitarian assistance efforts have included earthquake relief efforts in Morocco in March 1960, typhoon relief operations in the Philippines in July 1972 and hurricane relief operations in Central America in November 1998, as well as hundreds of other disaster relief activities, rescues at sea, emergency medical aid, and refugee assistance. Following the 26 December 2004 earthquake and tsunami in the Indian Ocean, the U.S. Navy rushed ships, aircraft and supplies to assist in relief efforts.