Destructive tsunamis have occurred in all of the world's oceans and seas. In the second half of the 20th Century, Pacific-wide, destructive tsunamis occurred in 1946, 1952, 1957, 1960, and 1964. Many more tsunamis occurred in inland seas around the periphery of the Pacific Ocean, which were extremely destructive locally and claimed thousands of lives. Such localized tsunamis occurred in 1975, 1983, 1985, 1992, 1993, 1995, 1998, 1999 and 2001.
1st April, 1946, Aleutian Earthquake and Tsunami
The Aleutian Islands Earthquake occurred near Unimak Island in Alaska's Aleutian Island Chain and was followed by a Pacific-wide tsunami. This earthquake had a magnitude of 7.8 on the Richter scale, with its epicenter at 52.8 degree N, 163.5 degree W, and focal depth of 25 km. A gigantic wave of 35 meters destroyed completely the U.S. Coast Guard's Scotch Cap lighthouse on Unimak and killed all five of its occupants. The lighthouse was a steel-reinforced concrete structure standing about 30 meters above sea level. The tsunami caused 165 casualties and about 26 million dollar in damages. The tsunami is known as the April Fools Day Tsunami in Hawaii as people took the tsunami warning as an April Fool prank.
The 4 November, 1952, Kamchatka Earthquake and Tsunami
A strong earthquake (magnitude 8.2) off the coast of Kamchatka Peninsula generated a great destructive Pacific-wide tsunami. Its waves struck the Kamchatka Peninsula, the Kuril Islands and other areas of Russia's Far East, causing considerable damage and loss of life. The tsunami was widely observed and recorded in Japan, but there was no loss of life or damage there. There was considerable damage in the Hawaiian Islands and some damage in Peru and Chile. The tsunami was recorded or observed throughout the islands of the Pacific. In New Zealand waves reached height of 1m, and in Alaska, in the Aleutian Islands and in California waves of up to 1.4 meters were observed. The largest waves outside the generating area were observed in the Hawaiian Islands. Fortunately, no human lives were lost in Hawaii from this tsunami, but damages were extensive, ranging from $800,000- $1,000,000. In the Hawaiian island chain, the tsunami waves destroyed boats and piers, knocked down telephone lines, and caused extensive beach erosion.
The north shore of the Island of Oahu experienced higher waves of up to 4.5 meters. On the south shore of the island, tsunamis waves were powerful enough to throw a cement barge in the Honolulu Harbor into a freighter. The island of Hawaii experienced drag up to 6.1 meters. In Hilo, a small bridge connecting Coconut Island to the shore was destroyed by one of the tsunami waves lifting it off its foundation, then smashing it down. The effects of the tsunami in the generating area in Kamchatka, varied significantly. From Kamchatka Peninsula to Kronotsky Peninsula, the wave heights ranged from 0 to 5 meters. From Kronotsky Peninsula to Cape Shipursky the heights ranged from 4-13 meters. The highest wave of 13 meters was the third as observed at Olga Bay, where it caused considerable damage. Travel time of the first tsunami wave to Olga Bay was approximately 42 minutes after the earthquake. From Cape Shipursky to Cape Povorotny, the tsunami waves ranged from 1 to 10 meters and caused considerable loss of life and damage. At Avachinskaia Bay the tsunami height was 1.2 meters and its travel time was about 30 minutes. From Cape Povorotny to Cape Lopatkka the waves ranged from 5 to 15 meters. At Khodutka Bay a cutter was thrown 500 meters back from shore. On the West coast of Kamchatka Peninsula, the maximum tsunami run up at Ozernoe was 5 meters. At Alaid Island of the Kuril Island group, run up was 1.5 meters, while at Shumshu Island it ranged from 7-9 meters. At Paramushir Island, the waves ranged from 4-18.4 meters. At Severo - Kurilsk on Paramushir Island, the second wave was the highest reaching maximum run up of 15 meters. It destroyed most of the town and caused considerable loss of life. At Onekotan Island tsunami run up was 9 meters, while at Shiashkoton Island it was 8 meters and at Iturup Island 2.5 meters. Waves of up to 2 meters were observed at the Komandorsk Islands and at Okhotsk. At Sakhalin - Korsakov a 1-meter tsunami wave was observed.
The 9 March, 1957, Aleutian Earthquake and Tsunami
On March 9, 1957, an 8.3 magnitude earthquake occurred south of the Andreanof Islands, in the Aleutian Islands of Alaska. It happened in the same general area as that of April 1, 1946, and generated a Pacific-wide tsunami. Although no lives were lost, there was massive destruction of property in the Hawaiian Islands, with damage estimated at approximately $5 million. The waves were particularly high on the north shore of the island of Kauai where they reached a maximum height of 16 meters, flooding the highway and destroying houses and bridges. This was twice the height of the 1946 tsunami. At Hilo, Hawaii, the tsunami run up reached 3.9 m and there was damage to numerous buildings along the waterfront. Within Hilo Bay, Coconut Island was covered by 1 m of water and the bridge connecting it to the shore, as in 1952, was again destroyed.
The 22 May, 1960, Chilean Earthquake and Tsunami
The largest earthquake ( magnitude 9.5 on moment magnitude scale) of the 20th century occurred on May 22, 1960, off the coast of south central Chile. It generated a Pacific-wide tsunami, which was destructive locally in Chile and throughout the Pacific Ocean. The tsunami killed an estimated 2,300 people in Chile. There was tremendous loss of life and property in the Hawaiian Islands, in Japan and elsewhere in the Pacific. Destructive waves in Hilo, Hawaii, destroyed the waterfront and killed 61 people. Total damage was estimated at more than $500 million (1960 dollars).
The 27 March, 1960, Great Alaska Earthquake and Tsunami
This earthquake is also known as the Good Friday earthquake as it happened on the day of Good Friday at 5:36 P.M. AST (03:36 3/27 UTC), and had a moment magnitude of 9.2 and was 8.4 on Richter scale. It was the most powerful earthquake ever recorded in the U.S. and North America. The epicenter of the earthquake was 61.05, -147.48, 20 km north of Prince William Sound, 125 km (78 miles) east of Anchorage and 64 km (40 miles) west of Valdez.
The powerful earthquake caused some parts of Alaska to be liquefied, causing great damage to property and leading to landslides. The earthquake caused areas to be lifted by 15 m (50 feet) in certain areas, while many other areas subsided greatly. In addition to many local tsunamis generated within the Prince William Sound, vertical crustal displacements averaging 1.8 m (6 ft.) over an area of about 300,000 square kilometers (115,000 square miles) extending in the Gulf of Alaska's continental shelf, generated a Pacific-wide tsunamis. Its waves were very destructive in southeastern Alaska, in Vancouver Island (British Columbia), and in the U.S. States of Washington, California and Hawaii. The tsunami killed more than 120 people and caused more than $106 million in damages, making it the costliest ever to strike the Western United States and Canada. Five of Alaska's seven largest communities were devastated by the combination of earthquake and tsunami wave damage. Alaska's fishing industry and most seaport facilities were virtually destroyed. Tsunami waves at Kodiak Island washed away a total of 158 houses and buildings within two blocks of the waterfront. Fishing boats were carried hundreds of meters inland. The 1964 tsunami waves caused also extensive damage in Vancouver Island (British Columbia), and in the states of Washington, California and Hawaii, in the U.S.. The waves affected the entire California coastline, but were particularly high from Crescent City to Monterey ranging from 2.1 - 6.3 meters (7-21 feet). California was hit hardest, where waves reaching as much as 6 meters (20-21 feet) destroyed half of the waterfront business district. At Santa Cruz Harbor, the tsunami waves reached as high as 3.3 meters (11 feet) causing some damage. There was extensive damage in San Francisco Bay, the marinas in Marin County and at the Noyo, Los Angeles and Long Beach harbors. Estimated losses in California were between $1,500,000 and $2,375,000 (1964 dollars), while at Crescent City tsunami damage was estimated at $7,414,000.