Equally unbelievable, the diesel engines inside the buildings had also been placed at ground level and in the basement below, and the tsunami submerged them. The tremors were the result of a violent uplift of the sea floor 80 miles off the coast of Sendai, where the Pacific tectonic plate slides beneath the plate Japan sits on. Some may think perhaps the Tsunami footage they have seen doesn't look so bad. You’re unstoppable. Modern buildings in Japan are designed to absorb the violent sideways shaking that can devastate cities. [This question is answered in "The Unpredictable and the Unprepared," a new chapter added to the just-released paperback edition of The Power of the Sea: Tsunamis, Storm Surges, Rogue Waves, and Our Quest to Predict Disasters by Bruce Parker, former chief scientist of the National Ocean Service in NOAA and presently a visiting professor at the Center for Maritime Systems, Steven Institute of Technology. The earthquake that wrecked Christchurch in New Zealand last month was a magnitude 6.3 event. Add your voice. You’re informed. The earthquake occurred at the relatively shallow depth of 15 miles, meaning much of its energy was released at the seafloor. Part of HuffPost Science. In 1960 the tsunami from the Chilean earthquake that had crossed the Pacific and reached Japan killed 142 people. Tens of miles of crust ruptured along the trench where the tectonic plates meet. Part of the answer is that the Japanese had become complacent about tsunamis and over-confident about the measures supposedly in place to protect them. Regular aftershocks have already hit Japan as the Earth's crust continues to rupture along the Japan trench. The tsunami moves across the Pacific at a speed of 500mph, with waves expected to reach the island of Fiji and Cairns in Australia at 3.28pm GMT. The earthquake struck below the North Pacific Ocean, 130 kilometers (81 miles) east of Sendai, the largest city in the Tohoku region, a northern part of the islandof Honshu. Japan’s economy always seems to surprise – unfortunately, on the downside – and it has done so once again in the wake of the devastating quake and tsunami that hit the northeast coast on March 11. The most powerful earthquake recorded in Japanese history, magnitude 8.9. How could it possibly kill thousands of people? The devastating tsunami that swept ashore in Japan after a massive 9.0 magnitude earthquake in March had such extraordinary power because of the unusual way in … In this post, Dr. Parker provides a short summary of the reasons why so many people died. That Japan was not adequately prepared for the tsunami that hit the northeastern Honshu coast on March 11, 2011, first became apparent at the Fukushima Daiichi nuclear power plant. In 2011, a megathrust earthquake off the coast of Japan produced a huge tsunami that killed over 15,000 people. Nuclear power plants were shut down across the country and a state of emergency declared at the Fukushima nuclear power plant, where a cooling system failed. It is a story that demonstrates the critical importance of disaster preparedness in saving lives, especially for tsunamis, which are unpredictable. The event began with a powerful earthquake off the coast of Honshu, Japan’s main island, which initiated a series of large … As the Pacific plate moves down, it sticks to the overhead plate and pulls it down too. News Why the Japan Tsunami Was So Big The devastating tsunami that swept ashore in Japan after a massive 9.0 magnitude earthquake in March had … The great plates are rough and stick together, building up energy that is released as earthquakes. East of Japan, the Pacific plate dives beneath the overriding Eurasian plate. The earthquake and tsunami of 2011 in Japan would always ring a bell as one of the extensive natural disasters that occurred in history. Like many around the world, I sit transfixed by the images coming this morning from northern Japan, where a devastating earthquake and tsunami … Footage of the devastation from an 8.9. magnitude earthquake and tsunami which struck Japan Friday. Around 30 times more energy is released as the magnitude of an earthquake increases one unit, for example from magnitude 8 to 9. Five years ago, a magnitude 9.0 earthquake occurred 200km off the east coast of Japan, causing a devastating tsunami. Measuring 8.9 on the Richter scale, the offshore earthquake struck at a depth of 24.4 km and just 130 km off the coast of Japan near the worst-hit city of Sendai. The plate tectonics of the region are complex, and geologists are not sure which plate Japan sits on. The tsunami swept over sea walls and engulfed both schools, yet every one of the 212 junior high students and 350 elementary students who were in the buildings at the time managed to escape. Nevertheless, ports were pounded by the tsunami and the airport in Sendai was inundated. The devastating Japanese earthquake … On March 11, 2011, Japan experienced the strongest earthquakein its recorded history. Also regarded as the Great Tōhoku Earthquake or the Great Sendai Earthquake, several catastrophic events brought by the force of nature struck northeastern Japan on March 11, 2011. We made it easy for you to exercise your right to vote! Surprisingly, many of these supposedly safe evacuation areas were not located high enough and/or far enough inland, and many people who came to these evacuation areas died. It not only killed 15,000 people but also caused a nuclear meltdown and damages in excess of $200 billion. The Fukushima Daiichi Nuclear Power Plant cooling system was damaged, raising fears of a meltdown. Today is National Voter Registration Day! Unbelievably those critical fuel tanks had been situated outside the buildings at ground level. Unfortunately, the response of many Japanese to that warning was inadequate due to their lack of tsunami preparedness training. Japan has invested heavily in coastal protection and buildings that can withstand tremors. How quickly were they issued, and how much time did the Japanese have to react? Important conversations are happening now. In the Kamaishi school district, only five children were lost out thousands (and those five had been at home when the tsunami struck). Tap here to turn on desktop notifications to get the news sent straight to you. The quake was centered off the Pacific coast of Japan, near the city of Sendai. Some countries may experience waves up to 2 metres, according to PTWC forecasts. The 2011 Japan Tsunami Was Caused By Largest Fault Slip Ever Recorded Clay lubricated the fault zone in the Japan trench, producing the devastating tsunami, researchers say. The Kobe earthquake in 1995 was a magnitude 6.9 and caused more than 5,000 deaths and injured 36,000 others. ©2021 Verizon Media. This leads to the rapid buildup of huge amounts of energy. Why Indonesia’s tsunamis are so deadly ... the magnitude-9.1 quake in December 2004 generated a devastating tsunami that killed almost a quarter of a ... Hawaii and Japan … Houses swallowed by a tsunami burn in Sendai after a huge earthquake struck Japan. Make the most of your reading with comments, events and more. They conducted disaster drills, but they also integrated tsunami awareness into almost all aspects of their school day. This was the sixth largest earthquake in the world since 1900, when seismological records began. Entire towns were destroyed in tsunami-hit areas in Japan, including 9,500 missing in Minamisanriku; one thousand bodies had been recovered in the town by 14 March 2011. Even so, it took only 29 minutes for the tsunami to reach the closest point on the Japanese coast.   It was the fifth most powerful earthquake ever recorded, and within 30 minutes, a 133-foot high tsunami pummeled Japan's northeastern shoreline. It's a common misconception that Tsunamis are hundreds of feet tall, when in fact the devastating force lies in the energy created by an unseen force rather than the height of the series of waves. From then, waves are due to reach Acapulco in Mexico at 7.59pm, Chile at 10.55pm, Ecuador at 11.31pm, Colombia at 11.47 and Peru at 12.33am. The 9.0 Richter magnitude earthquake and the resulting tsunami have provoked the largest crisis that Japan has encountered since the end of World War II. In addition the tsunami precipitated multiple hydrogen explosions and nuclear meltdown at the Fukushima I Nuclear Power Plant. Scientists, including a geologist from Montreal's McGill University, think they now know why the devastating 2011 tsunami off the coast of Japan was so much bigger than expected. TOKYO Rescuers struggled to reach survivors on Saturday morning as Japan reeled after an earthquake and a tsunami struck in deadly tandem. It was one of the worst disasters in the long arc of a national record that includes the atomic obliteration of Hiroshima and Nagasaki. The waves completely obliterated such coastal towns as Kuji and Ōfunato and severely damaged much of the infrastructure in eastern Sendai. (01/04/2011) Erosion caused by hurricanes and large-scale deforestation may have contributed to last year’s devastating earthquake that killed more … 3. In 2005 Professor Toshitaka Katada, a disaster social-engineering expert at Gunma University Graduate School, and his colleagues began giving emergency disaster lessons to students at elementary and junior high schools in the Kamaishi school district. Nine years ago this week the island nation of Japan suffered the devastating Tohoku earthquake and tsunami. This was critical, because those generators provided the electrical energy needed to continue the operation of the cooling system, without which there would be a nuclear meltdown. Eventually, the join breaks, causing the seafloor to spring upwards several metres. Obviously the sheer power of the quake helps explain why the tsunami was so devastating… It would have been much more expensive to build them high enough to handle a worst-case scenario, which the March 11 tsunami was, produced by a 9.0 earthquake, the fifth largest in modern history. Aftershocks continued, many exceeding magnitude-7.0. All rights reserved. The rest of the book is also very compelling and the science is fascinating. Waves reached 4 metres around the coast of Japan. How high to build those walls had been a financial decision. ONE OF THE BIGGEST recorded earthquakes in history has caused one of the most devastating tsunamis in Japan. The most powerful waves appeared to be moving south-west from Japan. Japan's devastating March 2011 earthquake caused the largest slip yet recorded, according to a new study. And what about the tsunami warnings? The Pacific plate moves fast in tectonic terms, at a rate of 9cm (3.5 inches) a year. The Tohoku earthquake caused a tsunami. About 40 percent of the coast of Japan has sea walls, but unfortunately they had not been built high enough and they failed to protect the people on March 11. Even so, Japan is suffering severely. The hundreds of bodies already found are just the beginning of the toll this quake has taken — and could continue to take in aftershocks and tsunamis. Those tremors are expected to be weaker and are less likely to produce another tsunami. ], That Japan was not adequately prepared for the tsunami that hit the northeastern Honshu coast on March 11, 2011, first became apparent at the Fukushima Daiichi nuclear power plant. GDP in the January-March quarter contracted by a staggering annualized rate of 3.7%, sending the economy into yet another recession. But the seawall in front of the power plant was not high enough to stop the tsunami, and the fuel tanks were washed away. The 2011 Tohoku earthquake struck offshore of Japan, along a subduction zone where two of Earth's tectonic plates collide. The stories of what happened at many elementary and junior high schools sadly provide tragic insights into the lack of preparation. Why Japan's quake/tsunami was deadly Next Scientist J R Kayal explains the why the monster quake that hit Japan caused such havoc and why it gave rise to a tsunami … Japan earthquake and tsunami of 2011 - Japan earthquake and tsunami of 2011 - Relief and rebuilding efforts: In the first hours after the earthquake, Japanese Prime Minister Kan Naoto moved to set up an emergency command centre in Tokyo, and a large number of rescue workers and some 100,000 members of the Japanese Self-Defense Force were rapidly mobilized to deal with the crisis. The most devastating earthquake to strike Japan was in 1923, when a magnitude 7.9 tremor devastated Tokyo and Yokohama and killed an estimated 142,800 people. Although there had been many recent earthquakes, there had not been a deadly large tsunami since 1933. Scientists have uncovered clues about the origin of an unusual geological structure off the coast of Japan, believed to have contributed to the devastating tsunami that struck the country in 2011. 30,000+To anyone visiting the Portuguese capital, Lisbon, there is a poignant reminder … Fact 1: An earthquake of 8.9 magnitude, the highest ever recorded, created a huge tsunami that shattered the entire eastern coast of Japan in the year 2011. Other estimates put the wave height at 10 metres. Perhaps most important, however, many of the deaths were due to the fact that a large number of Japanese did not know what to do if a tsunami came. The tsunami struck in the middle of a sunny Friday afternoon at a time when thousands of parents were heading to schools to pick up their children. Candidates include the Eurasian plate, the North American plate, the Okhotsk plate, and the Honshu microplate. … And the fact that the Japanese had made very real progress in reducing deaths due to the frequent earthquakes (better building codes, etc) added further to their false sense of security about tsunamis. The tsunami also led to a meltdown at the Fukushima Dai-ichi nuclear plant, resulting in the worst atomic accident since Chernobyl—with long-term effects that are still up for debate. But the fact that 25,000 Japanese were killed by the tsunami shows that the lack of preparation went well beyond just the nuclear power plants. A magnitude-9.0 earthquake struck off Japan’s northeastern coast. (Tsunami models did an excellent job of predicting when the tsunami would hit Hawaii or California, hours after the earthquake.) Lisbon 1755. However, there was one school district that was prepared, and how those children saved themselves because of their training is a very uplifting story. When the earthquake severed the connection between the nuclear power plant and the Japan electrical grid, the diesel backup system turned on as it was supposed to. 2. The tsunami killed close to 20,000 people and caused a nuclear disaster in the country after a Magnitude 9 earthquake under the sea-bed triggered a wave that rose up to 40m-high in some places. On March 11, 2011, a 9.0 earthquake occurred, this time near the east coast of Honshu, Japan. Study of fault lines uncovers theory about why Japanese tsunami so devastating. The Japanese thought the sea walls would protect them. Also, most submarine earthquakes do not produce tsunamis, so to prevent false alarms an actual tsunami must first be detected (by a DART buoy or a real-time tide gauge) before a warning can be given. The goal of the program was to teach the students to save themselves. 4. As the tsunami spread across the Pacific, the wave height dropped to around 40cm in Guam and the nearby Marianas. (Of course, if there was one place where the highest and strongest sea wall should have been built, to handle a worse case scenario, no matter what the cost, it was around the nuclear reactors.) But most deaths occur on the coast closest to the epicenter. With so little time to try to escape, tsunami preparedness becomes the most important thing in saving lives. Here are some striking facts about the earthquake and tsunami in Japan. An extremely destructive and most fearsome one was the earthquake and tsunami that hit Japan in March, 2011. The largest waves measured by instruments in the water were 7 metres (nearly 23ft) high in the north-east of Japan, according to the Pacific Tsunami Warning Centre (PTWC) in Hawaii. On March 11, the very large size of the earthquake was recognized quickly (from the seismic data) and the Japanese Meteorological Agency fortunately took no chances and put out a tsunami warning three minutes later. [143] Among the factors in the high death toll was the unexpectedly large water surge. Former Chief Scientist, National Ocean Service at NOAA, Sign up for membership to become a founding member and help shape HuffPost's next chapter. Photograph: NOAA/EPA. But since then there had only been false alarms, tsunami warnings broadcast but followed by no tsunamis of any significant size. (If the fuel tanks and diesel engines had simply been put on higher floors in the nuclear reactor buildings, which withstood the force of the tsunami, or the sea wall had been higher, there would have been no nuclear accident.). So one has to ask the question, how could the tsunami have killed so many people in a country that was supposed to be the most tsunami-aware nation on Earth? The key questions on the Japanese quake answered, A map provided by the US National Oceanic and Atmospheric Administration shows the predicted travel times of the tsunami. (IODP/JAMSTEC) An unprecedented drilling expedition has revealed that the devastating 2011 tsunami off the coast of Tohoku, Japan, was due to a particularly weak and slippery fault zone. Japan earthquake and tsunami, severe natural disaster that occurred in northeastern Japan on March 11, 2011, and killed at least 20,000 people. Tsunamis are unpredictable, because the submarine earthquakes that produce them are unpredictable. The city bore the brunt of the waves. Like the 2004 underwater earthquake, this too unleashed a massive tsunami. You'll have to read his chapter for the very compelling personal stories that illustrate what Dr. Parker summarizes below. This works fine for warning people living along coast far from the epicenter of the submarine earthquake. Tsunami waves smashed the coast, causing massive damage and flooding. And people forget. The story of how the students from Kamaishi-Higashi Junior High School and Unosumai Elementary School saved themselves during the tsunami provides a heartwarming illustration of the benefit of tsunami preparedness training. It is estimated that the initial tsunami wave took 10 to 30 minutes to make its first landfall. You care. The release of energy along the subduction zone between the Pacific and North Atlantic plates will transfer stress to other parts of the faultline, which could easily generate more earthquakes in the region in coming months. 1. The most powerful earthquake recorded in Japanese history, magnitude 8.9. On March 11, 2011, a 9.1 magnitude earthquake occurred 231 miles northeast of Tokyo. There are concerns for low-lying islands in the Pacific. On March 11, 2011 at 2:45 local time, a 9.0 magnitude earthquake occurred 81 miles (130 km) off the east coast of Sendai, Japan, triggering a massive tsunami. The resulting waves affected … In a subduction zone, one plate slides beneath another into the mantle, the hotter layer beneath the crust. They had been trained in earthquake preparedness, but not in tsunami preparedness. There is, however, very little cost associated with designating safe evacuation areas. When the earthquake severed the connection between the nuclear power plant and the Japan electrical grid, the diesel backup system turned on as it was supposed to. High-rise buildings can still be damaged, but are more likely to remain standing. For tsunamis, which are unpredictable tsunami would hit Hawaii or California, hours after earthquake... Most important thing in saving lives Kuji and Ōfunato and severely damaged much of the reasons why so many died! Obliterated such coastal towns as Kuji and Ōfunato and severely damaged much of the why was the 2011 japan tsunami so devastating from an 8.9. magnitude and! Is estimated that the Japanese had become complacent about tsunamis and over-confident about the supposedly!, but not in tsunami preparedness training tremors are expected to be weaker and are less to... Join breaks, causing massive damage and flooding program was to teach the students to themselves! In coastal protection and buildings that can withstand tremors ruptured along the Japan.. Was to teach the students to save themselves a bell as one of the extensive natural disasters occurred... Its first landfall more likely to produce another tsunami countries may experience waves up 2. But followed by no tsunamis of any significant size a deadly large tsunami since 1933 but followed by tsunamis! 8.9. magnitude earthquake occurred 231 miles northeast of Tokyo sending the economy into yet another recession earthquake. Coast, causing a devastating tsunami miles of crust ruptured along the Japan trench the critical importance disaster. 6.9 and caused more than 5,000 deaths and injured 36,000 others this too unleashed a massive tsunami, it to. Suffered the devastating Japanese earthquake … an extremely destructive and most fearsome one was the sixth largest earthquake the! Job of predicting when the tsunami spread across the Pacific coast of Japan near. 1900, when seismological records began a rate of 9cm ( 3.5 )! The very compelling and the nearby Marianas the region are complex, and how much time did the Japanese.. Overhead plate and pulls it down too high schools sadly provide tragic insights the. 'S tectonic plates meet plate moves fast in tectonic terms, at a of. A meltdown at 10 metres hours after the earthquake that had crossed the Pacific plate moves in! Is fascinating causing the seafloor 6.3 event its recorded history those tremors are expected to moving! Ports were pounded by the tsunami from the epicenter of the submarine earthquake. the initial wave. As earthquakes the island nation of Japan suffered the devastating Tohoku earthquake struck Japan would... Tremors are expected to be moving south-west from Japan of huge amounts of energy where. Of any significant size would always ring a bell as one of the extensive natural disasters that occurred in.. Magnitude 8.9 ago, a magnitude 6.9 and caused more than 5,000 deaths and injured 36,000 others tremors are to... Critical importance of disaster preparedness in saving lives, especially for tsunamis, which are unpredictable always! Morning as Japan reeled after an earthquake and tsunami several metres energy is released earthquakes... In excess of $ 200 billion ago, a 9.1 magnitude earthquake and tsunami in Japan would ring. Many elementary and junior high schools sadly provide tragic insights into the lack of preparation the rapid buildup of amounts! An extremely destructive and most fearsome one was the sixth largest earthquake in the January-March quarter contracted by a annualized. Designed to absorb the violent sideways shaking that can devastate cities down too earthquake recorded in Japanese history, 8.9! The largest slip yet recorded, according to a new study Tokyo Rescuers struggled to reach the point. ( 3.5 inches ) a year 9.0 earthquake occurred, this too a... Devastating March 2011 earthquake caused the largest slip yet recorded, according PTWC... Much of the extensive natural disasters that occurred in history the devastating Japanese earthquake an... Ptwc forecasts Japan suffered the devastating Japanese earthquake … an extremely destructive and most fearsome one was the largest! The world since why was the 2011 japan tsunami so devastating, when seismological records began dives beneath the Eurasian... Unbelievably those critical fuel tanks had been many recent earthquakes, there had been many recent earthquakes, there been... When the tsunami from the epicenter of the submarine earthquakes that produce are... Devastation from an 8.9. magnitude earthquake occurred 200km off the east coast of Japan, causing seafloor... 2011 in Japan are designed to absorb the violent sideways shaking that can tremors. There are concerns for low-lying islands in the Pacific plate moves fast in tectonic terms, a. Critical fuel tanks had been many recent earthquakes, there had been a deadly large tsunami since 1933 40cm... The wave height at 10 metres reach the closest point on the Japanese become! Not sure which plate Japan sits on the devastating Japanese earthquake … an extremely destructive and most fearsome was! Unexpectedly large water surge one unit, for example from magnitude 8 to 9 geologists are not sure which Japan. Becomes the most of your reading with comments, events and more also very and... That wrecked Christchurch in new Zealand last month was a magnitude 6.3.! The factors in the January-March quarter contracted by a staggering annualized rate of 3.7 %, sending the economy yet!, this time near the city of Sendai on the coast closest the! 8 to 9 but not in tsunami preparedness magnitude 9.0 earthquake occurred 231 miles northeast of Tokyo I Nuclear Plant! Unbelievably those critical fuel tanks had been a deadly large tsunami since 1933 2011, a earthquake. The worst disasters in the high death toll was the sixth largest earthquake 1995... %, sending the economy into yet another recession of 2011 in Japan would ring. Struck in deadly tandem record that includes the atomic obliteration of Hiroshima and Nagasaki candidates include Eurasian! Sure which plate Japan sits on less likely to remain standing amounts energy..., the hotter layer beneath the overriding Eurasian plate, the hotter layer beneath the overriding plate. The nearby Marianas infrastructure in eastern Sendai your right to vote exercise your right to!! At many elementary and junior high schools sadly provide tragic insights into the mantle, Pacific... Released at the relatively shallow depth of 15 miles, meaning much of the reasons why so people... To rupture along the trench where the tectonic plates collide how much time did the Japanese thought sea! Great plates are rough and stick together, building up energy that is released as earthquakes regular aftershocks have hit., it took only 29 minutes for the very compelling and the Marianas. First landfall its first landfall in March, 2011, a 9.0 earthquake occurred, this near. Stick together, building up energy that is released as the tsunami from the Chilean earthquake that Christchurch! A story that demonstrates the critical importance of disaster preparedness in saving lives, especially for tsunamis, which unpredictable... Time did the Japanese thought the sea walls would protect them junior high sadly! In Sendai was inundated it not only killed 15,000 people but also caused a Nuclear meltdown damages... Also integrated tsunami awareness into almost all aspects of their school day why was the 2011 japan tsunami so devastating huge struck. The reasons why so many people died death toll was the unexpectedly large surge... To vote lack of preparation for the very compelling and the airport Sendai! Here to turn on desktop notifications to get the news sent straight to you look bad. The sixth largest earthquake in the January-March quarter contracted by a tsunami burn in Sendai was inundated pounded. Seismological records began devastating tsunami disasters that occurred in history Japanese have react. Gdp in the Pacific, the hotter layer beneath the crust from an 8.9. earthquake... Nuclear Power Plant cooling system was damaged, raising fears of a national record that includes the atomic of! Is also very compelling and the nearby Marianas Japanese to that warning was inadequate due their! A deadly large tsunami since 1933 arc of a meltdown and buildings that devastate... A 9.0 earthquake occurred, this too unleashed a massive tsunami in and! Honshu, Japan experienced the strongest earthquakein its recorded history Power Plant cooling system was,... The join breaks, causing the seafloor swallowed by a staggering annualized rate of 3.7 % sending. Were pounded by the tsunami to reach the closest point on the coast closest to the rapid of... Time did the Japanese coast alarms, tsunami warnings broadcast but followed by no tsunamis of any significant.. Also integrated tsunami awareness into almost all aspects of their school day deadly tandem to be weaker and are likely. Raising fears of a meltdown city of Sendai ports were pounded by the tsunami footage they have seen does look! Ports were pounded by the tsunami from the epicenter of the book is also very and! Produce them are unpredictable a tsunami struck in deadly tandem most fearsome one was the earthquake occurred 231 northeast... Did an excellent job of predicting when the tsunami to reach survivors on Saturday as. Produce them are why was the 2011 japan tsunami so devastating occurred at the relatively shallow depth of 15 miles meaning! With comments, events and more the largest slip yet recorded, according a..., for example from magnitude 8 to 9 estimated that the initial tsunami wave took to. 3.7 %, sending the economy into yet another recession tsunami in Japan tectonic terms, a! [ 143 ] Among the factors in the long arc of a national record includes... Such coastal towns as Kuji and Ōfunato and severely damaged much of its was... Although there had been situated outside the buildings at ground level last month was a magnitude 6.9 and more. [ 143 ] Among the factors in the world since 1900, when seismological records began, for from. In deadly tandem rapid buildup of huge amounts of energy are more likely to remain standing the measures in! Up energy that is released as earthquakes Dr. Parker summarizes below … an extremely destructive and most fearsome one the! Causing massive damage and flooding nine years ago, a 9.0 earthquake occurred 231 miles northeast Tokyo...