11 March 2011- Massive 8.9 Earthquake Hits Japan & Causes Tsunami Of Japan -Pray ForJapan
A powerful earthquake has struck off Japan's north-eastern coast, shaking buildings in Tokyo and forcing people out of their homes. Japan issued its most serious tsunami warning, saying a wave as high as 20 ft could strike the coast near Miyagi prefecture.The massive 8.8 magnitude quake struck about 382 kilometers northeast of Tokyo.
I saw this and had to upload it. This is very tragic with what just happened. I hope it goes all well for them in japan!!! No copyright intended. This is just to spread the word of the disaster happening in Japan.
Pray For Japan !!!!!
Breaking News - A magnitude 8.9 earthquake slammed Japan's northeastern coast Friday, unleashing a 13-foot (4-meter) tsunami that swept boats, cars, buildings and tons of debris miles inland. Fires triggered by the quake burned out of control up and down the coast.
The quake struck at 2:46 p.m. and was followed by five powerful aftershocks within about an hour, the strongest measuring 7.1. The U.S. Geological Survey upgraded the strength of the first quake to a magnitude 8.9, while Japan's meteorological agency measured it at 8.4.
11 March 2011- Massive 8.9 Earthquake Hits Japan & Causes Tsunami Of Japan -Pray ForJapan !!!
duminică, 13 martie 2011
Tsunami Of Japan - The most-powerful earthquake in Japan
The most-powerful earthquake in Japan's recorded history struck off the country's northeast coast on Friday, leaving hundreds of people dead, injured or missing.
The 8.9-magnitude earthquake triggered a deadly tsunami that washed far inland, swamping towns, sweeping away a train and sparking massive fires that burned through the night.
The exact death toll was not immediately clear, but there were reports that 200 to 300 bodies were found in the northeastern coastal city of Sendai alone. Another 547 are missing and 798 people were injured, police said.
Kaoru Ishikawa, the Japanese ambassador to Canada, told CBC News that officials haven't determined how many people had died after the devastating quake and tsunami.
"We are trying indeed to check what's going on, but unfortunately the scope of the casualties we don't know yet," he said.
Local media are reporting that the death toll is expected to climb and could pass 1,000.
The offshore quake struck at 2:46 p.m. local time at a depth of 24 kilometres about 125 kilometres off the coast, according to the U.S. Geological Survey.
Massive fires triggered by the quake were burning in many communities, and at least one oil refinery was ablaze, officials said.
A state of emergency was declared near a damaged nuclear power plant, prompting the government to order that about 3,000 people leave the area.
The 8.9-magnitude earthquake triggered a deadly tsunami that washed far inland, swamping towns, sweeping away a train and sparking massive fires that burned through the night.
The exact death toll was not immediately clear, but there were reports that 200 to 300 bodies were found in the northeastern coastal city of Sendai alone. Another 547 are missing and 798 people were injured, police said.
Kaoru Ishikawa, the Japanese ambassador to Canada, told CBC News that officials haven't determined how many people had died after the devastating quake and tsunami.
"We are trying indeed to check what's going on, but unfortunately the scope of the casualties we don't know yet," he said.
Local media are reporting that the death toll is expected to climb and could pass 1,000.
The offshore quake struck at 2:46 p.m. local time at a depth of 24 kilometres about 125 kilometres off the coast, according to the U.S. Geological Survey.
Massive fires triggered by the quake were burning in many communities, and at least one oil refinery was ablaze, officials said.
A state of emergency was declared near a damaged nuclear power plant, prompting the government to order that about 3,000 people leave the area.
What Is A Tsunami For Japan ?
What Is A Tsunami For Japan ?
Tsunamis are a source of severe damage and loss of life in Japan. These occurrences are not just contemporary experiences but have been happening over several hundred years. Given the data, it can be concluded that tsunamis are a permanent physical characteristic of Japan. They can hit anywhere in Japan, but they are most common on the Pacific coast. In particular, high-energy tsunamis are frequently experienced in the Sanriku region in the northeast part of the main island of Honshu. Two tsunamis, however, hit the Sea of Japan coast in 1983 and 1993, which underscores the need for vigilance in this area as well.
Given Japan's location, it is safe to say that the tsunamis are not a temporary characteristic. Japan is located in the "Ring of Fire" - an area known for its large earthquakes that result in deadly tsunamis. In less than a day, these tsunamis can travel from one side of the Pacific to the other. Because Japan is surrounded by water, the tsunami threat is immediate. Another reason why Japan is linked to tsunamis is because of plate tectonics. It is located near the colliding margins of four tectonic plates - the Eurasian, the North American, the Pacific, and the Philippine. These plates move very rarely and when they do it is not much. Therefore, Japan will be near this collision center for a long time coming. 80% of the world's tsunamis appear to be generated by undersea earthquakes around the Pacific Rim. Japan is hit by nearly all of them. This is not likely to change.
On several occasion, tsunamis various meters high have swept across Japan, washing whole villages into the sea. Inhabitants of Japan have learned to deal with this, however. The Japan Meteorological Agency is able to contact the people minutes after an earthquake is reported. This can give the people some warning to leave their homes and rush to the mainland. Leaving no hope for their homes, at least they can save their own lives.
Read a paper that describes national coastal conditions and trends, and why Japan is so vulnerable to natural disasters such as tsunamis - Vulnerability and Adaption to Sea-Level Rise in Japan
Read about the Tsunami Engineering Division - This Disaster Control Research Center studies tsunamis from the engineering point of view and have made numerous efforts to develop a numerical simulation technique in order to help control tsunami disasters.
Read another paper about the Japanese coastal zone environment and ways to prevent its natural disasters - A Theory of Integrated Coastal Zone Management in Japan
Tsunamis are a source of severe damage and loss of life in Japan. These occurrences are not just contemporary experiences but have been happening over several hundred years. Given the data, it can be concluded that tsunamis are a permanent physical characteristic of Japan. They can hit anywhere in Japan, but they are most common on the Pacific coast. In particular, high-energy tsunamis are frequently experienced in the Sanriku region in the northeast part of the main island of Honshu. Two tsunamis, however, hit the Sea of Japan coast in 1983 and 1993, which underscores the need for vigilance in this area as well.
Given Japan's location, it is safe to say that the tsunamis are not a temporary characteristic. Japan is located in the "Ring of Fire" - an area known for its large earthquakes that result in deadly tsunamis. In less than a day, these tsunamis can travel from one side of the Pacific to the other. Because Japan is surrounded by water, the tsunami threat is immediate. Another reason why Japan is linked to tsunamis is because of plate tectonics. It is located near the colliding margins of four tectonic plates - the Eurasian, the North American, the Pacific, and the Philippine. These plates move very rarely and when they do it is not much. Therefore, Japan will be near this collision center for a long time coming. 80% of the world's tsunamis appear to be generated by undersea earthquakes around the Pacific Rim. Japan is hit by nearly all of them. This is not likely to change.
On several occasion, tsunamis various meters high have swept across Japan, washing whole villages into the sea. Inhabitants of Japan have learned to deal with this, however. The Japan Meteorological Agency is able to contact the people minutes after an earthquake is reported. This can give the people some warning to leave their homes and rush to the mainland. Leaving no hope for their homes, at least they can save their own lives.
Read a paper that describes national coastal conditions and trends, and why Japan is so vulnerable to natural disasters such as tsunamis - Vulnerability and Adaption to Sea-Level Rise in Japan
Read about the Tsunami Engineering Division - This Disaster Control Research Center studies tsunamis from the engineering point of view and have made numerous efforts to develop a numerical simulation technique in order to help control tsunami disasters.
Read another paper about the Japanese coastal zone environment and ways to prevent its natural disasters - A Theory of Integrated Coastal Zone Management in Japan
Historical Tsunamis in Japan
Historical Tsunamis in Japan
1. Chart of Japanese Tsunamis
Chart of Japanese Tsunamis
The 1700 Cascadia Earthquake
On January 6, 1700, at about 9:00 p.m. Pacific Standard Time, a gigantic earthquake occurred sixty to seventy miles off the Pacific Northwest coast. The quake violently shook the ground for three to five minutes and was felt along the coastal interior of the Pacific Northwest. A tsunami formed, reaching about 33 feet high along the coast, and then traveled across the Pacific Ocean and hit the east coast of Japan.
The earthquake ruptured what is known as the Cascadia subduction zone - the area of overlap between two of the tectonic plates that make up the earth's surface. These plates are the Juan de Fuca and the North American. The Cascadia subduction zone extends from Vancouver Island, British Columbia south to cape Mendocino in Northern California. The earthquake dropped the entire Pacific Northwest ocean coastline three to six feet.
The tsunami traveled across the Pacific Ocean for some 10 hours and at midnight on January 27, 1700, local time, it hit the east coast of Japan. By then the tsunami was only 6-10 feet high but it still did significant damage.
The very existence of this magnitude 9 earthquake was unknown just twenty years ago. An early breakthrough came in 1987 when U.S. Geological Survey geologist Brian Atwater reported geological traces of giant earthquakes along Washington's Pacific coast. These traces included groves of trees that were killed when an earthquake lowered forests into the salt water. Another important clue was reported a few years later when the earthquake was dated to the decades between 1680 and 1720. This clue came from radiocarbon tests by Minze Stuiver of the University of Washington. Meanwhile in Japan, several researchers were following these developments. They consulted their nation's archives of old writings about earthquakes and tsunamis. For the period between 1680 and 1720 they found one orphan tsunami that could have come from Cascadia. That tsunami occurred in January of 1700. Finally, a final clue was found in the groves of killed trees on the Washington coast. Using annual growth rings in the trees, David Yamaguchi of Seattle and Gordon Jacoby of Columbia University showed that the trees lived through the 1699 growing season but were dead by the following spring - exactly the dates expected if the earthquake occurred in January 1700.
Article on the 1700 tsunami - "Rememberance of Waves Past"
December 31, 1703 - Genroku
The Genroku Earthquake is thought to have been an interplate earthquake whose focal region extended from Sagami Bay to the tip of the Boso Peninsula as well as the area along the Sagami Trough in the open sea southeast of the Boso Peninsula. It generated strong ground motion over a wide area centered in the southern Kanto region. Reports on the damage theorized that ground motion corresponded to a seismic intensity of 6 on the Richter scale. This earthquake then resulted in a tsunami that hit the coastal areas of Japan and the Boso Peninsula. The tsunami caused more than 6,500 fatalities on the peninsula. In Awa, Japan, however, the tsunami was reported to have killed more than 100,000 people - possibly the most destructive tsunami ever.
3.June 15, 1896 - Honshu, Japan
On June 15, 1896, nearly 22,000 Japanese lost their lives due to one of the most devastating tsunamis in Japanese history.
The earthquake occurred on the evening of the Boy's Festival Day (Tango-no-sekku) on the lunar calendar, and many people had gathered indoors for the parties. This delayed evacuation and is the reason cited for the drowning deaths of thousands. The tsunami, which was generated by the earthquake off the coast of Sanriku, Japan, attained a height of 25 meters and instantly swept away all houses and people when it reached land.
One hundred years after this earthquake, two researchers became determined to figure out its source. Yuichiro Tanioka of the Department of Geological Science of the University of Michigan, and Ann Arbor and Kenji Satake of the Seismotectonics Section of the Geological Survey of Japan, Tsukuba, developed a model using a modern computer simulation. The results of their research indicate that the source of the earthquake was very close to the Japan trench. They estimated that the fault that generated the earthquake had a width of 50 kilometers, and the movement along the fault was 5.7 meters. The earthquake ruptured beneath an accretionary wedge, a relatively shallow area. If a substantial occurs in the same area in the future, a resulting tsunami could be unusually large, like the 1896 event.
4. September 1, 1923 - Kanto
The morning of Saturday, September 1, 1923, was very hot with strong gusts of wind that followed rain. Soon it was almost noon and the area around Sagami Bay, Japan began to shake in what amounted to a magnitude 8.3 earthquake. A section of the fault under the bay was measured to have been displaced nearly 240m, and although no surface faults appeared, new ridges 180 to 300 ft tall appeared on the sea floor in line with a pre-existing volcanic chain. The ground was uplifted and hundreds of landslides were triggered. This Kanto Earthquake generated a tsunami approximately 30-40ft high which crashed unto shore about 5 minutes later. Many were killed, houses were destroyed, and nearly 45% of the population was left unemployed. In all, seven prefectures were affected by the tsunami. These were Tokyo, Kanagawa, Shizuoka, Chiba, Saitama, Yamanashi, and Ibaraki. The greatest destruction occurred at Yokohama, which at the time was the premier commercial port of Japan. An unusual characteristic of the Great Kanto Earthquake was the dramatic upheaval and depression of the ground. The earth was uplifted as high as 24ft, substantially changing the shape of the shoreline.
No less ferocious in nature than the earthquake itself was the conflagration that followed. When it struck, coal or charcoal cooking stoves were in use throughout Toyko and Yokohama in preparation for the noon-time meal and fires sprang up everywhere within moments of the quake. Fire-induced wind spawned numerous cyclones, which further spread the flames. The uplifting and depression of the land also resulted in landslides. Towns were buried by a massive mudflow, killing hundreds.
The combination of the earthquake and tsunami created massive destruction. The total number of houses partially or completely destroyed numbered in excess of 694,000. In addition to houses, the list of damage includes buildings, dams, tanks, tunnels, sewers, towers, canals, retaining walls, and lighthouses. Telephone and telegraph systems were demolished leaving the people completely cut off from the outside world. Streets were choked with rubble making them impassible by automobile.
5. December 21, 1946 & March 4, 1952
The Nankai Earthquake of December 21, 1946, was an interplate earthquake with a source region in an area along the Nankai Trough. The seismic ground motion from this earthquake is estimated to have corresponded to a seismic intensity of 6 in JMA scale. A tsunami generated by this earthquake caused significant damage in many areas. The tsunami height was 4 to 7 meters along the Pacific coast. It did reach as high as 11m in some places, however. This tsunami caused damage through the reversed flow in the Kizugawa River and the Ajigawa River in Osaka. There were a total of 1,443 dead or missing, 3,842 injured, and 9,000 houses completely collapsed. There were a total of forty aftershocks of magnitude 5 or larger accompanying this earthquake that lasted until April of 1947, resulting in crustal deformation of the land.
According to the Japan Meteorological Agency, the March 4, 1952 Tokachi-oki Earthquake corresponded to a seismic intensity of 8.1. The maximum tsunami height reached 3 to 4m on the Pacific coast f eastern Hokkaido. It caused 28 deaths, injured 287, and destroyed 8,534 houses. 6. May 26, 1983
A tsunami occurred on May 26, 1983, at the middle of the East Sea and propagated across the basin and caused substantial damages along the coasts of Japan and Korea. The tsunami, generated by a magnitude 7.9 earthquake destroyed 700 boats and 59 houses for a total of $800 million in property damage in Japan. 104 people drowned in Japan and 3 in Korea. The earthquake itself damaged 5,100 houses and ended several lives. As a result of the combination of earthquake and tsunami, a process of liquefaction occurred. Liquefaction happens in areas where unconsolidated materials are saturated with water. Under these conditions, what had been a stable soil turns into a fluid that is not capable of supporting buildings or other structures.
Liquefaction
July 12, 1993
Over the years, the Japanese people have grown accustomed to the numerous tsunami occurrences. They know that they cannot control the forces of nature, but they can become prepared. On the night of July 12, 1993, their preparations faced a brutal test. A magnitude 7.8 earthquake in the Sea of Japan generated a tsunami that struck various parts of the small island of Okushiri.
Simulation of the 1993 tsunami
Five minutes after the main shock the Japan Meteorological Agency issued a warning over television and radio that a major tsunami was on its way. By then, 10- to 20-meter waves had struck the coastline nearest the sources, claiming a number of victims before they could flee. However, 1,200 people escaped the waves when they ran inland after feeling the shaking.
The $600 million in property losses were attributed to the tsunami. This tsunami causes spectacular localized damage, especially on the southwestern shores of Hokkaido and on Okushiri Island. Numerous fires, fueled by above-ground kerosene and propane tanks, broke out following the tsunami, adding to the property loss and misery. The tsunami stripped plants and grasses from the hillside leaving debris in the overhead utility wires. Vertical runup measurements varied between 15 and 30m over a 20km portion of the southern part of Okushiri Island, with several 10m values on the northern portion. As of July 21, 185 fatalities were confirmed, with 120 attributed to the tsunami. The death toll was expected to rise, as missing persons were included among the fatalities.
Article on the July 12, 1993 tsunami - Okushiri, Japan
Recent Destructive Tsunamis
1. Chart of Japanese Tsunamis
| | | |
| Aug-10-1901 | Japan (Sanriku) | 18 |
| Jul-07-1905 | Japan (Fukushima) | 41 |
| Jan-12-1914 | Japan (Seikaido) | 35 |
| Sep-01-1923 | Japan (Tokaido) | 2,144 |
| Mar-07-1927 | Japan (South-West Honshu) | 325 |
| Mar-02-1933 | Japan (Sanriku) | 3,000 |
| May-29-1938 | Japan (Hokkaido) | 1 |
| Aug-02-1940 | Japan (Hokkaido) | 7 |
| Nov-18-1941 | Japan (Seikado) | 2 |
| Dec-21-1946 | Japan (Nankaido) | 1,997 |
| Mar-04-1952 | Japan (Southeast Hokkaido) | 33 |
| May 16-1968 | Japan Trench | 52 |
| May-26-1983 | Japan (Noshro) | 103 |
| Jul-12-1993 | Japan | 120 |
The 1700 Cascadia Earthquake
On January 6, 1700, at about 9:00 p.m. Pacific Standard Time, a gigantic earthquake occurred sixty to seventy miles off the Pacific Northwest coast. The quake violently shook the ground for three to five minutes and was felt along the coastal interior of the Pacific Northwest. A tsunami formed, reaching about 33 feet high along the coast, and then traveled across the Pacific Ocean and hit the east coast of Japan.
The earthquake ruptured what is known as the Cascadia subduction zone - the area of overlap between two of the tectonic plates that make up the earth's surface. These plates are the Juan de Fuca and the North American. The Cascadia subduction zone extends from Vancouver Island, British Columbia south to cape Mendocino in Northern California. The earthquake dropped the entire Pacific Northwest ocean coastline three to six feet.
The tsunami traveled across the Pacific Ocean for some 10 hours and at midnight on January 27, 1700, local time, it hit the east coast of Japan. By then the tsunami was only 6-10 feet high but it still did significant damage.
The very existence of this magnitude 9 earthquake was unknown just twenty years ago. An early breakthrough came in 1987 when U.S. Geological Survey geologist Brian Atwater reported geological traces of giant earthquakes along Washington's Pacific coast. These traces included groves of trees that were killed when an earthquake lowered forests into the salt water. Another important clue was reported a few years later when the earthquake was dated to the decades between 1680 and 1720. This clue came from radiocarbon tests by Minze Stuiver of the University of Washington. Meanwhile in Japan, several researchers were following these developments. They consulted their nation's archives of old writings about earthquakes and tsunamis. For the period between 1680 and 1720 they found one orphan tsunami that could have come from Cascadia. That tsunami occurred in January of 1700. Finally, a final clue was found in the groves of killed trees on the Washington coast. Using annual growth rings in the trees, David Yamaguchi of Seattle and Gordon Jacoby of Columbia University showed that the trees lived through the 1699 growing season but were dead by the following spring - exactly the dates expected if the earthquake occurred in January 1700.
Article on the 1700 tsunami - "Rememberance of Waves Past"
December 31, 1703 - Genroku
The Genroku Earthquake is thought to have been an interplate earthquake whose focal region extended from Sagami Bay to the tip of the Boso Peninsula as well as the area along the Sagami Trough in the open sea southeast of the Boso Peninsula. It generated strong ground motion over a wide area centered in the southern Kanto region. Reports on the damage theorized that ground motion corresponded to a seismic intensity of 6 on the Richter scale. This earthquake then resulted in a tsunami that hit the coastal areas of Japan and the Boso Peninsula. The tsunami caused more than 6,500 fatalities on the peninsula. In Awa, Japan, however, the tsunami was reported to have killed more than 100,000 people - possibly the most destructive tsunami ever.
| Date (UTC) | Time (UTC) | Source Location | Magnitude | Source Type | Max Runup in AOR (m) |
| June 15, 1896 | 10:32:00 | 39.5N 144.0E | 7.2 | Earthquake | 1.5 |
The earthquake occurred on the evening of the Boy's Festival Day (Tango-no-sekku) on the lunar calendar, and many people had gathered indoors for the parties. This delayed evacuation and is the reason cited for the drowning deaths of thousands. The tsunami, which was generated by the earthquake off the coast of Sanriku, Japan, attained a height of 25 meters and instantly swept away all houses and people when it reached land.
One hundred years after this earthquake, two researchers became determined to figure out its source. Yuichiro Tanioka of the Department of Geological Science of the University of Michigan, and Ann Arbor and Kenji Satake of the Seismotectonics Section of the Geological Survey of Japan, Tsukuba, developed a model using a modern computer simulation. The results of their research indicate that the source of the earthquake was very close to the Japan trench. They estimated that the fault that generated the earthquake had a width of 50 kilometers, and the movement along the fault was 5.7 meters. The earthquake ruptured beneath an accretionary wedge, a relatively shallow area. If a substantial occurs in the same area in the future, a resulting tsunami could be unusually large, like the 1896 event.
4. September 1, 1923 - Kanto
The morning of Saturday, September 1, 1923, was very hot with strong gusts of wind that followed rain. Soon it was almost noon and the area around Sagami Bay, Japan began to shake in what amounted to a magnitude 8.3 earthquake. A section of the fault under the bay was measured to have been displaced nearly 240m, and although no surface faults appeared, new ridges 180 to 300 ft tall appeared on the sea floor in line with a pre-existing volcanic chain. The ground was uplifted and hundreds of landslides were triggered. This Kanto Earthquake generated a tsunami approximately 30-40ft high which crashed unto shore about 5 minutes later. Many were killed, houses were destroyed, and nearly 45% of the population was left unemployed. In all, seven prefectures were affected by the tsunami. These were Tokyo, Kanagawa, Shizuoka, Chiba, Saitama, Yamanashi, and Ibaraki. The greatest destruction occurred at Yokohama, which at the time was the premier commercial port of Japan. An unusual characteristic of the Great Kanto Earthquake was the dramatic upheaval and depression of the ground. The earth was uplifted as high as 24ft, substantially changing the shape of the shoreline.
No less ferocious in nature than the earthquake itself was the conflagration that followed. When it struck, coal or charcoal cooking stoves were in use throughout Toyko and Yokohama in preparation for the noon-time meal and fires sprang up everywhere within moments of the quake. Fire-induced wind spawned numerous cyclones, which further spread the flames. The uplifting and depression of the land also resulted in landslides. Towns were buried by a massive mudflow, killing hundreds.
The combination of the earthquake and tsunami created massive destruction. The total number of houses partially or completely destroyed numbered in excess of 694,000. In addition to houses, the list of damage includes buildings, dams, tanks, tunnels, sewers, towers, canals, retaining walls, and lighthouses. Telephone and telegraph systems were demolished leaving the people completely cut off from the outside world. Streets were choked with rubble making them impassible by automobile.
5. December 21, 1946 & March 4, 1952
The Nankai Earthquake of December 21, 1946, was an interplate earthquake with a source region in an area along the Nankai Trough. The seismic ground motion from this earthquake is estimated to have corresponded to a seismic intensity of 6 in JMA scale. A tsunami generated by this earthquake caused significant damage in many areas. The tsunami height was 4 to 7 meters along the Pacific coast. It did reach as high as 11m in some places, however. This tsunami caused damage through the reversed flow in the Kizugawa River and the Ajigawa River in Osaka. There were a total of 1,443 dead or missing, 3,842 injured, and 9,000 houses completely collapsed. There were a total of forty aftershocks of magnitude 5 or larger accompanying this earthquake that lasted until April of 1947, resulting in crustal deformation of the land.
According to the Japan Meteorological Agency, the March 4, 1952 Tokachi-oki Earthquake corresponded to a seismic intensity of 8.1. The maximum tsunami height reached 3 to 4m on the Pacific coast f eastern Hokkaido. It caused 28 deaths, injured 287, and destroyed 8,534 houses.
A tsunami occurred on May 26, 1983, at the middle of the East Sea and propagated across the basin and caused substantial damages along the coasts of Japan and Korea. The tsunami, generated by a magnitude 7.9 earthquake destroyed 700 boats and 59 houses for a total of $800 million in property damage in Japan. 104 people drowned in Japan and 3 in Korea. The earthquake itself damaged 5,100 houses and ended several lives. As a result of the combination of earthquake and tsunami, a process of liquefaction occurred. Liquefaction happens in areas where unconsolidated materials are saturated with water. Under these conditions, what had been a stable soil turns into a fluid that is not capable of supporting buildings or other structures.
Liquefaction
July 12, 1993
Over the years, the Japanese people have grown accustomed to the numerous tsunami occurrences. They know that they cannot control the forces of nature, but they can become prepared. On the night of July 12, 1993, their preparations faced a brutal test. A magnitude 7.8 earthquake in the Sea of Japan generated a tsunami that struck various parts of the small island of Okushiri.
Simulation of the 1993 tsunami
Five minutes after the main shock the Japan Meteorological Agency issued a warning over television and radio that a major tsunami was on its way. By then, 10- to 20-meter waves had struck the coastline nearest the sources, claiming a number of victims before they could flee. However, 1,200 people escaped the waves when they ran inland after feeling the shaking.
The $600 million in property losses were attributed to the tsunami. This tsunami causes spectacular localized damage, especially on the southwestern shores of Hokkaido and on Okushiri Island. Numerous fires, fueled by above-ground kerosene and propane tanks, broke out following the tsunami, adding to the property loss and misery. The tsunami stripped plants and grasses from the hillside leaving debris in the overhead utility wires. Vertical runup measurements varied between 15 and 30m over a 20km portion of the southern part of Okushiri Island, with several 10m values on the northern portion. As of July 21, 185 fatalities were confirmed, with 120 attributed to the tsunami. The death toll was expected to rise, as missing persons were included among the fatalities.
Article on the July 12, 1993 tsunami - Okushiri, Japan
Recent Destructive Tsunamis
| Location | Date | Damage (in Millions) | Earthquake Magnitude | Max Runup | Deaths |
| Nicaragua | September 1992 | Extensive | 7.2 | 9.7 | 170 |
| Indonesia | December 1992 | Extreme | 7.5 | 26.0 | 1000 |
| Japan Sea | July 1993 | 600 | 7.8 | 31 | 185 |
| Indonesia | June 1994 | 2.2 | 7.2 | 14 | 250 |
| Kuril Islands | October 1994 | Local | 6.8 | ? | 1 |
| Alaska | November 1994 | 21 | Landslide | 10 | 1 |
| Philippines | November 1994 | 25 | 7.0 | 10 | 62 |
History Of Tsunamis In Japan
History Of Tsunamis In Japan
Ring of Fire
The Pacific Ocean is the world's largest ocean, covering more than one-third of the total surface area of our planet. It is surrounded by a series of mountain chains, deep ocean trenches, and island arcs, sometimes called a "Ring of Fire." The great size of the Pacific Ocean and the large earthquakes associated with the "Ring of Fire" combine to produce deadly tsunamis. In less than a day, these tsunamis can travel from one side of the Pacific to the other. However, people living near areas where large earthquakes occur may find that the tsunami waves will reach their shores within minutes of the earthquake. For these reasons, the tsunami threat to Japan can be be immediate.
Many subduction-zone volcanoes in the "Ring of Fire" also cause tsunamis. Here volcanism is associated with subduction of the Pacific seafloor. As oceanic plates sink, they carry sediments and oceanic crust containing abundant water to great depths. The presence of water contributes to the high gas content and explosive nature of volcanoes that make up the "Ring of Fire."
90% of the world's earthquakes and 81% of the world's largest earthquakes occur along the Ring of Fire. The next most seismic region (5�6% of earthquakes and 17% of the world's largest earthquakes) is the Alpide belt which extends from Java to Sumatra through the Himalayas, the Mediterranean, and out into the Atlantic. The Mid-Atlantic Ridge is the third most prominent earthquake belt.
The Ring of Fire is a direct consequence of plate tectonics and the movement and collisions of crustal plates.
The eastern section of the ring is the result of the Nazca Plate and the Cocos Plate being subducted beneath the westward moving South American Plate.
A portion of the Pacific Plate along with the small Juan de Fuca Plate are being subducted beneath the North American Plate. Along the northern portion the northwestward moving Pacific plate is being subducted beneath the Aleutian Islands arc.
Further west the Pacific plate is being subducted along the Kamchatka - Kurile Islands arcs on south past Japan. The southern portion is more complex with a number of smaller tectonic plates in collision with the Pacific plate from the Mariana Islands, the Philippines, Bougainville, Tonga, and New Zealand.
Indonesia lies between the Ring of Fire along the northeastern islands adjacent to and including New Guinea and the Alpide belt along the south and west from Sumatra, Java, Bali, Flores, and Timor.
The December 2004 earthquake just off the coast of Sumatra was actually a part of the Alpide belt. The famous and very active San Andreas Fault zone of California is a transform fault which offsets a portion of the East Pacific Rise under southwestern United States and Mexico. The motion of the fault generates numerous small earthquakes, at multiple times a day, most of which are too small to be felt.
Major volcanic areas in the Ring of Fire
Plate Tectonics
Another reason why Japan is continuously hit by tsunamis is because of plate tectonics. On several occasions, tsunamis various meters high have swept across Japan, washing whole villages into the sea. Such events are not infrequent around the tectonically active Pacific Ocean basin. Most tsunamis are caused by submarine earthquakes. Thus, they are most common in the Pacific Ocean, where earthquakes occur frequently in the subduction zones that form the "Ring of Fire." The central most reason why tsunamis hit Japan, however, is because Japan is precariously situated near the colliding margins of four tectonic plates - the Eurasian, the North American, the Pacific, and the Philippine. The subduction of these plates create high levels of seismic activity, leading to more tsunamis.
This Dynamic Earth is a great website that describes the background of the plate tectonics theory, how it developed, and also information for a deeper understanding of the concept. It includes great information and even cool pictures!! Please try it!!
How do we detect tsunamis?
Japan Meteorological Agency
The Japan Meteorological Agency (JMA) is a unique agency in the government of Japan. It is responsibile for issuing tsunami forecasts by analyzing seismic data from the nationwide observation network on a real-time basis, 24 hours a day and 7 days a week. In order that authorities of the national government and local governents can take emergency response to reduce tsunami disasters properly and immediately, the JMA issues tsunami warning/advisory three minutes after an earthquake occurrence if a tsunami is anticipated to have been generated by it. The JMA is using the empirical relationship between an earthquake location/magnitude and tsunami generation for its tsunami forecast at present. Tsunamis can sometimes propogate far from epicenters. The tsunamis originally caused near the American continent can travel across the Pacific Ocean and hit the Japanese archipelago. JMA issues tsunami forecasts for such long-propogated tsunamis for the purpose of mitigating these disasters, in co-operation with the Pacific Tsunami Warning Center (PTWC) in Hawaii, which exchanges information on tsunamis among pan-Pacific countries.
Go to the Japan Meteorological Agency website
Another description of the JMA at www.goin.nasda.go.jp/GOIN/JMA/
Ring of Fire
The Pacific Ocean is the world's largest ocean, covering more than one-third of the total surface area of our planet. It is surrounded by a series of mountain chains, deep ocean trenches, and island arcs, sometimes called a "Ring of Fire." The great size of the Pacific Ocean and the large earthquakes associated with the "Ring of Fire" combine to produce deadly tsunamis. In less than a day, these tsunamis can travel from one side of the Pacific to the other. However, people living near areas where large earthquakes occur may find that the tsunami waves will reach their shores within minutes of the earthquake. For these reasons, the tsunami threat to Japan can be be immediate.
Many subduction-zone volcanoes in the "Ring of Fire" also cause tsunamis. Here volcanism is associated with subduction of the Pacific seafloor. As oceanic plates sink, they carry sediments and oceanic crust containing abundant water to great depths. The presence of water contributes to the high gas content and explosive nature of volcanoes that make up the "Ring of Fire."
Pacific Ring of Fire
90% of the world's earthquakes and 81% of the world's largest earthquakes occur along the Ring of Fire. The next most seismic region (5�6% of earthquakes and 17% of the world's largest earthquakes) is the Alpide belt which extends from Java to Sumatra through the Himalayas, the Mediterranean, and out into the Atlantic. The Mid-Atlantic Ridge is the third most prominent earthquake belt.
The Ring of Fire is a direct consequence of plate tectonics and the movement and collisions of crustal plates.
The eastern section of the ring is the result of the Nazca Plate and the Cocos Plate being subducted beneath the westward moving South American Plate.
A portion of the Pacific Plate along with the small Juan de Fuca Plate are being subducted beneath the North American Plate. Along the northern portion the northwestward moving Pacific plate is being subducted beneath the Aleutian Islands arc.
Further west the Pacific plate is being subducted along the Kamchatka - Kurile Islands arcs on south past Japan. The southern portion is more complex with a number of smaller tectonic plates in collision with the Pacific plate from the Mariana Islands, the Philippines, Bougainville, Tonga, and New Zealand.
Indonesia lies between the Ring of Fire along the northeastern islands adjacent to and including New Guinea and the Alpide belt along the south and west from Sumatra, Java, Bali, Flores, and Timor.
The December 2004 earthquake just off the coast of Sumatra was actually a part of the Alpide belt. The famous and very active San Andreas Fault zone of California is a transform fault which offsets a portion of the East Pacific Rise under southwestern United States and Mexico. The motion of the fault generates numerous small earthquakes, at multiple times a day, most of which are too small to be felt.
Major volcanic areas in the Ring of Fire
- In South America the Nazca plate is colliding with the South American plate. This has created the Andes and volcanoes such as Cotopaxi and Azul.
- In Central America, the tiny Cocos plate is crashing into the North American plate and is therefore responsible for the Mexican volcanoes of Popocatepetl and Paricutun (which rose up from a cornfield in 1943 and became a instant mountains).
- Between Northern California and British Columbia, the Pacific, Juan de Fuca, and Gorda plates have built the Cascades and the infamous Mount Saint Helens, which erupted in 1980.
- Alaska's Aleutian Islands are growing as the Pacific plate hits the North American plate. The deep Aleutian Trench has been created at the subduction zone with a maximum depth of 25,194 feet (7679 meters).
- From Russia's Kamchatka Peninsula to Japan, the subduction of the Pacific plate under the Eurasian plate is responsible for Japanese islands and volcanoes (such as Mt. Fuji).
- The final section of the Ring of Fire exists where the Indo-Australian plate subducts under the Pacific plate and has created volcanoes in the New Guinea and Micronesian areas. Near New Zealand, the Pacific Plate slides under the Indo-Australian plate.
Plate Tectonics
Another reason why Japan is continuously hit by tsunamis is because of plate tectonics. On several occasions, tsunamis various meters high have swept across Japan, washing whole villages into the sea. Such events are not infrequent around the tectonically active Pacific Ocean basin. Most tsunamis are caused by submarine earthquakes. Thus, they are most common in the Pacific Ocean, where earthquakes occur frequently in the subduction zones that form the "Ring of Fire." The central most reason why tsunamis hit Japan, however, is because Japan is precariously situated near the colliding margins of four tectonic plates - the Eurasian, the North American, the Pacific, and the Philippine. The subduction of these plates create high levels of seismic activity, leading to more tsunamis.
This Dynamic Earth is a great website that describes the background of the plate tectonics theory, how it developed, and also information for a deeper understanding of the concept. It includes great information and even cool pictures!! Please try it!!
How do we detect tsunamis?
Japan Meteorological Agency
The Japan Meteorological Agency (JMA) is a unique agency in the government of Japan. It is responsibile for issuing tsunami forecasts by analyzing seismic data from the nationwide observation network on a real-time basis, 24 hours a day and 7 days a week. In order that authorities of the national government and local governents can take emergency response to reduce tsunami disasters properly and immediately, the JMA issues tsunami warning/advisory three minutes after an earthquake occurrence if a tsunami is anticipated to have been generated by it. The JMA is using the empirical relationship between an earthquake location/magnitude and tsunami generation for its tsunami forecast at present. Tsunamis can sometimes propogate far from epicenters. The tsunamis originally caused near the American continent can travel across the Pacific Ocean and hit the Japanese archipelago. JMA issues tsunami forecasts for such long-propogated tsunamis for the purpose of mitigating these disasters, in co-operation with the Pacific Tsunami Warning Center (PTWC) in Hawaii, which exchanges information on tsunamis among pan-Pacific countries.
Go to the Japan Meteorological Agency website
Another description of the JMA at www.goin.nasda.go.jp/GOIN/JMA/
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