TOKYO -- Small earthquakes rock Tokyo all the time. So when the floor started swaying Friday, as I stopped to buy cough drops at a subway kiosk, I hardly blinked.
The shopkeeper off-handedly remarked there was a quake. I shrugged in acknowledgment.
But as tremors grew more violent and the walls began to sway and signs began to bounce off the ceiling like yo-yos and the whole concourse became enveloped in a groaning, banging clatter -- we shot each other nervous looks, as if to say, "This is long-awaited Big One!"
That's when people started running from the station. Some of them screaming.
It turned out to be the Big One. But not for Tokyo. The epicenter was hundreds of miles to the north, off the Pacific coast. Still, the 8.9-magnitude earthquake, the biggest to ever hit Japan, was the worst the capital has seen in many people's memories -- and triggered near panic.
Within minutes of the first hit, thousands of people were pouring onto the street to avoid being crushed in their offices. Many wore company-issued hardhats that are part of the crisis kits here.
Subway and train lines were immediately shut down. Streets were impassable with traffic, sirens blared, empty taxis were impossible to find. Elevators were dysfunctional. And falling glass, building tiles, sign posts and electric wires made venturing far on foot hazardous.
By Saturday night, life had returned to normal, more or less, despite constant aftershocks. There were never any power outages or major structural damage in this city that 12 million call home.
But train and mobile phone service was still spotty. And fires and suspended production at oil refineries have triggered fuel shortages and lines at gasoline stations around Tokyo.
Meanwhile, runs on ATMs and supermarkets made it hard to get food or the cash to buy it. Bread, crackers, instant noodles, canned fish, bottled water -- anything nonperishable -- had disappeared from the shelves. Milk? Forget about it.
Stores were still bare Monday, as Tokyo residents braced for a round of rolling blackouts. The local utility, Tokyo Electric Power Co., was shutting down parts of the grid to conserve electricity because so many of its power plants were off line.
Most notably, its nuclear plants that were on the brink of meltdown.
Fear of nuclear disaster quickly superseded that of killer quakes or tsunamis, for people in Japan's largest city, which is only 150 miles from the dysfunctional reactors.
And the race against time to cool the reactors before they belch forth a radioactive cloud is 24-7 TV news here -- with some stations offering advice on how to best shield yourself from harm. Helpful hint: Wear a surgical mask and cover all exposed skin. Take showers often.
Reports say there is a 70 percent chance of an aftershock with a magnitude of 7.0 or greater in the coming days. That could further hinder rescue efforts and work on the nuclear plants.
Tokyo still lives in the shadow of the devastating 7.9-magnitude earthquake that wiped out huge swaths of the capital in 1923 and claimed some 140,000 lives. Scientists estimate a quake of that magnitude targets the capital area on a 70-year cycle. And we are long overdue.
So we are still waiting for the Big One in Tokyo. But this most recent disaster offers an ugly preview of the chaos and destruction that it will unleash.