00:00On March 11, 2011, the Earth itself was knocked sideways.
00:03At 2.46 p.m., a 9.0 magnitude earthquake struck Japan, the most earthquake-proof nation on Earth,
00:09and shook the entire country for six straight minutes. The quake was so powerful it shifted
00:13the planet's rotation axis by 7 inches and moved the Japanese archipelago 2.5 kilometers to the east.
00:19Yet here is the strangest part, the earthquake itself killed fewer than 200 people.
00:23So how did nearly 20,000 lives disappear? The water withdrew first, receding far too fast,
00:29far too far. Then a 40-meter wall of water raced across 800 kilometers of coastline.
00:34That day, the living were not enough to carry the dead. And 100 kilometers away,
00:39a nuclear power plant had just lost all power. Everyone was running. But 50 people turned and
00:44walked back toward the sea. When that wall of water hit, it was not a single wave.
00:49The entire sea surface was lifted and pushed forward as one mass. In one town,
00:53a 24-year-old announcer named Endo kept broadcasting into his microphone,
00:57a tsunami is approaching. Moved to higher ground immediately. Colleagues told him to flee.
01:02He stayed. The water swallowed the three-story disaster center, and 42 staff were lost.
01:08His voice was the last living sound many of the town's 17,000 people ever heard.
01:12But that same voice drove 7,000 others to run uphill, and survive.
01:16Japan should not have lost this badly. It was the world's benchmark for earthquake engineering.
01:21Buildings were built to the highest seismic standards. Schools ran evacuation drills every year.
01:27The coastline was lined with concrete breakwaters. The port of Kamaishi had built a seawall that took
01:3230 years to finish, reaching 63 meters below the seabed, the deepest in the world, a Guinness World Record.
01:37On the day of the tsunami, that world-class wall was snapped like a twig by the force of the
01:41water.
01:42Why did it fail? Because this earthquake was outside the historical record.
01:46At the Japan Trench, the Pacific Plate is being forced beneath the North American Plate at about
01:508 centimeters a year. For centuries, the plates locked, building up enormous strain.
01:55Then, on that day, the accumulated energy of hundreds of years released all at once.
02:00The seafloor was shoved 50 meters sideways and thrust 16 meters upward. Gravity dropped that
02:05displaced column of water back down, and that is where the 40-meter wave came from.
02:09Not wind. Not tide. The earth itself had flipped the ocean.
02:14A 2013 study revealed a deeper cause. The research vessel Chikyu drilled an 820-meter hole into the
02:20Japan Trench and found a layer of clay less than 5 meters thick. This clay had almost no friction.
02:25Once the fault began to slip, the two plates slid past each other with almost no resistance,
02:29all the way down. A 5-meter layer of clay triggered a magnitude 9 earthquake,
02:34releasing the energy of 600 million Hiroshima bombs detonated at once.
02:37Science explained why the quake was so large. But it did not explain why human failure proved
02:42deadlier than the disaster itself. 1400 years earlier, in 869 AD, a massive earthquake known
02:48as the Jogun Quake had struck the same waters, its tsunami flooding the plains more than 4 kilometers
02:52inland. By 2011, geologists had already assembled teams, dug trenches along the coast, and built models.
02:59Their conclusion was written clearly, the northeastern waters were capable of producing
03:03another quake of the same magnitude. That research was submitted for review in March 2011,
03:08just days before the earthquake arrived first. The warnings were even clearer inside the nuclear
03:12industry. In 2008, an engineer at Tokyo Electric ran a fresh tsunami simulation.
03:17The result, the Fukushima Daiichi plant could face a tsunami up to 15.7 meters high.
03:23The plant's seawall was only 5.7 meters. The report reached the company's vice president,
03:28who rejected the reinforcement plan, the data, he said, needed more study. That report sat suppressed
03:33for three years. It was finally submitted to regulators on March 7, 2011. Four days later,
03:39the sea came. A 15 meter wall of water poured over the 5 meter seawall and flooded the plant's basement,
03:45where the emergency generators had been placed. The cooling systems lost power. The reactor cores
03:50overheated, and the fuel rods reacted with seawater at high temperature, generating hydrogen.
03:54On March 12, Unit 1 exploded. On the 14th and 15th, Units 3 and 4 followed. The cores began to
04:01melt
04:02down, and radioactive gas leaked into the air. The plant was spinning out of control. Japan's
04:07prime minister later admitted he considered evacuating the entire Tokyo region. Standing
04:11inside the plant was a 56-year-old man named Yoshida, the site manager. Tokyo Electric Headquarters
04:17ordered a stop to the seawater injection, arguing the salt water would corrode the equipment and ruin
04:21the reactors beyond reuse. Yoshida called over the man in charge of the pumps and said,
04:25headquarters want us to stop. I will say we stopped. But you keep pumping. He obeyed on the
04:31surface and defied the order in secret. The physicist Michio Kaku later said that was the
04:35single decision that prevented a full meltdown and total loss of control of the site,
04:38because they kept flooding the core with seawater. If Yoshida had truly obeyed that day,
04:43many nuclear experts believe the contamination could have blanketed all of eastern Japan,
04:46on the scale of Chernobyl. Now for the contrast. On the same day, in the same earthquake, closer to
04:52the epicenter, there was another nuclear plant, Anagawa, run by Tohoku Electric. All three of its
04:57reactors shut down safely. Nothing went wrong. In fact, the plant became a shelter, more than 3,000
05:04local residents who lost their homes moved in and stayed for three months. Why did it survive?
05:08Because of a man who had died 25 years earlier. His name was Hirai, a former president of Tohoku
05:14Electric. In 1968, when Anagawa was being designed, everyone said a 12 meter seawall was enough.
05:20He alone insisted on raising it to 14.8 meters, nearly five times the standard of the time.
05:25He pored over ancient records, studied the Jogun quake, and concluded the northeast would face
05:30another one. People thought he was overreacting. But his insistence persuaded the management.
05:35On March 11, 2011, the tsunami that reached Anagawa measured 13 meters. The wall stood at 14.8.
05:42A margin of 1.8 meters separated safety from catastrophe. Hirai died in 1986,
05:48he never lived to see his judgment vindicated. But the wall he insisted on building kept that promise for him.
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