Japan continues to be rattled by aftershocks, but the biggest shock for the country now that the 8.9 quake is over and day has broken in Japan may be in assessing the damage from the monster trembler and the subsequent tsunami.
Hours after the buildings stopped shaking, fires still burned and Tokyo remained largely paralyzed with phone and train service halted -- though as Saturday wore on train service began to come back. Nuclear plants were disabled and thousands of people were urged to evacuate because of high radiation levels.
The official death toll from Friday's earthquake and tsunami stands at 413, while 784 people were missing and 1,128 were reported injured according to the Associated Press.
However, many observers feared the numbers of dead and injured would soar as searchers gained access to the hardest hit areas.
Between 200 to 300 bodies were seen in Sendai, the coastal region hit hardest by the quake, though damage to roads and fear of more tsunamis reportedly kept officials from getting at them.
Japanese government officials were telling local media they were certain the death toll would rise to more than 1,000.
Many in Tokyo spent the night in their cars trying to get home because the highways were all closed and cars clogged the city's streets. Store shelves were stripped bare by shoppers and thousands more spent the night in their offices.
In the Shibuya area in the heart of Tokyo, a bank was filled with sleeping people.
It was harder to assess damage outside the capital because of cut phone communications. Much of the town of Kesennuma near Miyagi, burned during the night with no apparent hope of being extinguished, public broadcaster NHK said.
Japan's coast guard was searching for 80 dock workers on a ship that was swept away from a shipyard in Miyagi.
President Obama called the tsunami "catastrophic" and said help was on the way. The United States has one aircraft carrier in Japan and another is on the way, and a ship is also en route to Marianas Islands for assistance, Obama said.
In addition, a USAID Disaster Assistance Response Team is assembling to go to Japan, and the Pentagon is sending some P-3 Orion maritime surveillance aircraft to support the Japanese government by providing aerial reconnaissance over quake-damaged areas.
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The earthquake, the fifth largest in recorded history and the largest ever to hit Japan, struck about 2:46 p.m. local time. It triggered a tsunami that unleashed a menacing stew of debris with objects as large as ships, cars and houses coursing over the countryside and into towns, crushing buildings and everything in its path. Eerily, fires burned in the watery mess as it flowed along.
So far, there are no reports of American fatalities in Japan, but anxious posts on Facebook by Americans living there reveal the devastation in the hard-hit Sendai area.
One woman affiliated with a missionary school in Sendai sent a Facebook message to friends and family saying she and all of the 40 member staff at the MeySen School are luckily safe.
"We are all ok. Lots of messes, think fish tanks and china cabinets," Carrie Elizabeth Barnes Broman told friends in a message. "MeySen is housing staff and students' families in the school. ... No electricity or gas obviously - water available depending on building."
Randy Castle, an American man working in Japan, said his hotel lobby was full of people overnight who couldn't make it home from work.
"It started and it lasted a good five minutes, lots of shaking and very scary. I'm on the 11th floor, just down the street from the Tokyo tower," Castle said.
The Tokyo tower, a famed landmark in Japan, is now bent.
"It was a lot of swaying, you could hear the building creaking in it ... you could see the shades shaking back and forth," Castle said. "The people that I work with here in Tokyo, it was normal for them, but shortly after that it started to get scary the longer it went."
"We were just hanging out in Shibuya [Tokyo] today and walking down the street and all of a sudden felt like we were on a boat and looked up and tall buildings were going crazy, looking like they were going to tip over," said Kevin Williams, an American vacationing in Tokyo.
It's the strongest earthquake the world has seen since the 9.1 magnitude Indian Ocean quake in 2004, which triggered a massive tsunami. The combination of the quake and tsunami left 230,000 people dead.
The Japan quake hit at 2:46 p.m. local time in Japan, and lasted an astonishing five minutes. To put that in perspective, the devastating earthquake in Northridge, Calif., in 1994 lasted just six seconds.
"The bigger the earthquake, the larger the size of the fault that has to rupture to make it happen…you're seeing waves generated along a huge fault," Dr. Kate Hutton, a seismologist at the California Institute of Technology, said.
At least 80 aftershocks above magnitude 5.0 -- and some as large as 7.4 -- have struck Japan, reversing the path of rivers, washing away boats and cars, and leaving buildings shaking like jelly.
There are reports of a missing train full of dozens of commuters in the earthquake region and a boat ripped from the docks of Miyagi with 80 workers on board being swept out to sea in the tsunami.
"We have to watch for chemical explosions, gas leaks, fires ... the agony is just beginning," Dr. Michio Kaku, a physicist, said. "Earthquakes take place in stages. ... We are only in act one. We have yet to go to act two."
A "nuclear emergency" was declared at the Fukushima Daiichi power plant after a power outage disabled the cooling system at one reactor and pressure built up. Nearly 3,000 people were evacuated from the region surrounding the plant.
Later, the company in charge of the plant and another plant nearby reported four more reactors had cooling system failures, the Associated Press reported.
Kaku, a physicist who also has family in Japan, said that the tsunami struck in the pivotal "Ring of Fire," an arc of earthquake and volcanic zones stretching around the Pacific. The region is where 90 percent of the world's earthquakes occur.
ABC Radio and the Associated Press contributed to this report.