Originally published March 10, 2011 at 10:27 p.m., updated March 11, 2011 at 3:51 p.m.
A massive tsunami triggered by one of the largest earthquakes ever recorded smashed into Japan's eastern coast Friday, killing hundreds of people as it swept away boats, cars and homes. Officials were racing to prevent dangerous overheating at a nuclear power plant north of Tokyo. (Story continues below.)
Tsunami waves hit Hawaii hours later and warnings blanketed the entire Pacific, as far away as South America, Canada, Alaska and the entire U.S. West Coast.
The magnitude 8.9 earthquake rocked Japan at 2:46 p.m. local time — the biggest temblor to hit the country since officials began keeping records in the late 1800s. Dozens of cities and villages along a 1,300-mile stretch of coastline were shaken by violent tremors that reached as far away as Tokyo, hundreds of miles from the epicenter.
The seismic shaking unleashed a tsunami up to 30 feet high in some places, and more than 50 aftershocks followed, many of them magnitude 6.0 or greater.
Police said 200 to 300 bodies were found in the northeastern coastal city of Sendai in Miyagi prefecture, the city closest to the quake's epicenter. An additional 178 people were confirmed killed and nearly 600 were missing.
Police also said more than 900 people were injured. Japan's coast guard reported that it was searching for about 80 dock workers swept out to sea from a shipyard in Miyagi.
"The earthquake has caused major damage in broad areas in northern Japan," Prime Minister Naoto Kan said at a news conference.
Nuclear Power Plant Damage Prompts Evacuations
The massive quake caused a power outage that disabled a cooling system at a nuclear power plant 150 miles north of Tokyo, triggering the country's first-ever state of emergency for a nuclear facility.
Japan's nuclear safety agency said pressure inside one of six boiling water reactors at the Fukushima Daiichi plant had risen to 1.5 times the level considered normal. Nearly 3,000 people in Fukushima prefecture were ordered to evacuate the area, and residents were told to stay at least two miles away from the nuclear plant.
Japanese officials say that when the quake struck, the nuclear reactor in the plant's core shut down automatically, NPR's Jon Hamilton reported. But leftover radioactive materials will continue to produce intense heat for a day or two, so it's essential that pumps keep circulating cool water to prevent the core from melting.
The pumps lost their main power in the earthquake. And the backup system of diesel generators failed to kick in, perhaps because of damage from the tsunami.
That left only a battery backup, which is designed to operate for perhaps eight hours.
U.S. officials say they are working with the Japanese government to get a new power source in place before the reactor's core becomes dangerously hot.
Meanwhile, officials were considering the possibility of releasing slightly radioactive vapor to reduce pressure on the system.
Chief Cabinet Secretary Yukio Edano said the amount of radioactive element in the vapor would be "very small" and would not affect the environment or human health. "With evacuation in place and the ocean-bound wind, we can ensure the safety," he said at a televised news conference early Saturday.
Ippo Maeyama of Japan's Defense Ministry said dozens of troops trained for chemical disasters had been sent to the Fukushima plant in case of a radiation leak, along with four vehicles designed for use in atomic, biological and chemical warfare.
Officials said there was no risk of a radiation leak. Nuclear power plants like the one at Fukushima are designed to contain nuclear material even if the cooling system fails.
When the quake struck, the reaction in the core automatically shut down, officials said. But pumps used to circulate water to cool the 460-megawatt No. 1 reactor lost power and a back-up system of diesel generators also failed to kick in, leaving only a battery-powered system designed to operate for about eight hours.
Without pumps to circulate the coolant, it burns off more quickly. U.S. Secretary of State Hillary Clinton said Air Force planes carrying more coolant were en route to Japan.
Japan, which relies on nuclear power for nearly a third of its electricity generation, closed at least three other plants as a precaution after the reports of damage at Fukushima and another facility, according to the International Atomic Energy Agency.
In Miyagi prefecture, the turbine building of another nuclear power plant caught fire. Public broadcaster NHK showed footage of a large ship being swept away and ramming directly into a breakwater in Kesennuma city.
Airport Swamped, Hundreds Of Houses Swept Away
Japanese TV images from Sendai showed highways buckling and older wooded structures flattened by the force of the shaking. As the tsunami wave swept ashore, Sendai airport was instantly inundated. The wave washed through a fish market near the shoreline, picking up an entire parking lot full of cars and sweeping them into the sea.
In one town alone on the northeastern coast, Minami-soma, some 1,800 houses were destroyed or badly ravaged, a Defense Ministry spokeswoman said.
In Tokyo, video images showed a large building on fire and billowing smoke in the Odaiba district. The tremor bent the upper tip of the iconic Tokyo Tower, a 1,093-foot steel structure inspired by the Eiffel Tower in Paris.
Buildings shook violently and workers poured into the street for safety as the temblor hit, but there were few reports so far of collapsed buildings — a sign that stringent building codes may have averted a far greater disaster.
Osamu Akiya, 46, was working in Tokyo at his office in a trading company when the quake hit. It sent bookshelves and computers crashing to the floor, and cracks appeared in the walls.
"I've been through many earthquakes, but I've never felt anything like this," he said. "I don't know if we'll be able to get home tonight."
Tokyo airports closed and all public transportation was shut down. NHK said more than 4 million buildings were without power in the city and its suburbs.
As night fell and temperatures hovered just above freezing, tens of thousands of people remained stranded in Tokyo. The streets were jammed with cars, buses and trucks trying to get out of the city.
The city set up 33 shelters in city hall, on university campuses and in government offices, but many planned to spend the night at 24-hour cafes, hotels and offices.
"Normally, we're used to building shaking, but this just went on and on and on," Lucy Craft reported for NPR from Tokyo. She said she was in the building in Tokyo that houses Japan's Diet, or parliament, when the quake struck.
"The subways were stopped, most of the transportation links are halted now; the highways are closed; trains are not running. It's difficult to make phone calls," Craft said. "The country has just come to a screeching halt."
She said Japan spends huge amounts of money on disaster prevention and resistance. But even for a country used to earthquakes, this one was of horrific proportions.
Nations Stand Ready To Send Aid
The quake struck at a depth of six miles, about 80 miles off the eastern coast, according to the U.S. Geological Survey. The area is 240 miles northeast of Tokyo.
"The energy radiated by this quake is nearly equal to one month's worth of energy consumption" in the United States, USGS Scientist Brian Atwater told The Associated Press.
Edano, the Cabinet secretary, said the Defense Ministry was sending troops to the quake-hit region. A utility aircraft and several helicopters were on the way.
U.N. spokeswoman Elizabeth Byrs, speaking in Geneva, Switzerland, said 35 international search-and-rescue teams were on alert and would be dispatched immediately if Japan requested assistance.
Obama expressed his condolences and offered U.S. aid to Japan.
"Our hearts go out to our friends in Japan and across the region, and we're going to stand with them as they recover and rebuild from this tragedy," he said at a Friday afternoon news conference in Washington.
The president said the U.S. was sending an aircraft carrier to Japan and another ship to the Marianas Islands to assist as needed. The Defense Department also was working to account for all military personnel stationed in Japan, and the State Department was trying to account for all American citizens there.
Obama said he was heartbroken by the tragedy in Japan and that it was "a reminder of just how fragile life can be."
Earlier, he said U.S. officials were monitoring tsunamis in the Pacific and that he had ordered FEMA to be ready to assist Hawaii and any other affected U.S states and territories.
California's Gov. Jerry Brown has declared a state of emergency in four counties struck by tsunami waves.
Scientists say the tsunami surge will continue for about the next 10 hours.
Brown says the surge is causing extreme peril in Santa Cruz, San Mateo, Humbolt and Del Norte counties where waves have caused millions of dollars of damage. They've wiped out docks and damaged boats and washed onlookers off the shore.
One man is still missing.
Here in Southern California, there's little trace of the surge.
Local experts told KPBS that big tsunami waves are unlikely to hit San Diego's coast because of our distance from Japan and the geography of our ocean floor.
Nevertheless, local authorities have asked people to stay vigilant.
Early today, hundreds of people flocked to the beach along the county's 73-mile coastline. Many stood on the cliffs debating whether they'd seen the surge or not. Others got bored and left.
Local Japanese-American leaders announced that the Buddhist Temple of San Diego will hold a memorial service for quake victims at 7 p.m. on Saturday.
In Hawaii, where vulnerable areas were evacuated, waves about 3 feet high hit the islands of Oahu and Kauai at about 8:30 a.m. ET. Water rushed ashore in Honolulu, swamping Wakiki Beach but stopping short of the area's high-rise hotels. There were no immediate reports of damage.
The tsunami warning extended to a number of Pacific, Southeast Asian and Latin American nations, including Japan, Russia, Indonesia, New Zealand and Chile. In the Philippines, authorities said they expect a 3-foot high tsunami.
A History Of Killer Quakes
The area of Japan devastated by Friday's quake had been hit by several temblors in recent days, including a magnitude 7.3 event Wednesday.
Japan's worst previous quake was in 1923 in Kanto, a 7.9-magnitude temblor that killed 143,000 people, according to the USGS. A 6.9-magnitude quake in Kobe city in 1995 killed 6,400 people.
Japan lies on the "Ring of Fire" an arc of earthquake and volcanic zones stretching around the Pacific where about 90 percent of the world's quakes occur, including the one that triggered the Dec. 26, 2004, Indian Ocean tsunami that killed an estimated 230,000 people in 12 nations. A magnitude-8.8 temblor that shook central Chile last February also generated a tsunami and killed 524 people.
With reporting from NPR's Louisa Lim in Beijing; Lucy Craft in Tokyo; Lisa Schlein in Geneva; and Jon Hamilton in Washington. Material from The Associated Press was used in this story.