BENEATH the Japanese archipelago lies a mythical catfish, brutish and capricious. For most of the time, its head is pinned down by a granite keystone, held in place by the Shinto god of the earth. But occasionally, the god drops his guard. Then the fish thrashes, convulsing the earth. In mid-afternoon on March 11th a massive earthquake erupted, 24 kilometres (15 miles) down, off the north-east coast of Japan's main island. A tsunami followed. Cars, ships and buildings were swept away. People in Tokyo 370 kilometres away poured out of buildings as high-rises swayed. An anxious roar went up in the shopping district of Omote-Sando as the first of the aftershocks struck. After wreaking damage along low-lying parts of the coast, the tsunami rolled across the Pacific, testing the Pacific-wide early-warning system set up after the Boxing Day tsunami in 2004. Shares and the yen both fell.
This 8.9-magnitude quake has been described as the biggest on record in tremor-prone Japan. NHK, the national broadcaster, has uncertain reports on the number of dead and missing, but the combined totals are believed to be in the hundreds. The broadcaster says whole villages in parts of Japan's north-eastern Pacific coast were swept away by a tsunami reaching seven metres high. Images showed waves churning through hamlets in the flat farming communities near the sea, carrying ships, buses and houses far inland. In Ishinomaki, Miyagi prefecture, a ship with 100 people abroad was washed away. Their whereabouts are unknown. One giant wave washed through an airport in Sendai, the capital of Miyagi, leaving 1,300 people stranded on upper floors within.
Japanese are drilled from childhood to deal with quakes. Coping with the chaos of the real thing is another matter. Bullet-train services were immediately halted. A huge fire blazed at an oil refinery on Tokyo's outskirts and at least 50 fires have been reported elsewhere, including at factories belonging to Nissan and Sumitomo Metal. In Japan the fires caused by earthquakes, rather than the quakes themselves, are usually the main killers. But modern industries bring other earthquake-related concerns. At about 10pm local time, Yukio Edano, the chief cabinet secretary, issued a nuclear emergency warning for the Fukushima First Nuclear Power Plant in Fukushima prefecture. He said people within a 3km radius were being ordered to evacuate, while those living between 3km and 10km away were instructed to stay in their houses. He denied, though, that there was radioactive leakage.
The opposition Liberal Democratic Party, which has been doing its level best in recent weeks to topple the government of Naoto Kan, the prime minister, now says it will co-operate fully, including supporting special spending measures.
Tsunami warnings continue to be broadcast repeatedly on the television. Across Japan, millions braced for a miserable night of uncertainty. Electricity firms reported that in northern Japan, many homes were without power or phone lines; in the same area, snow is falling, and TV images showed people in evacuation shelters huddling in blankets. Tokyo got off relatively lightly, though most public transport ground to a halt, forcing commuters to walk often huge distances home. Shelves in the capital's convenience stores were almost bare, with long lines of people attempting to buy snacks and drinks.
But it is worth bearing in mind that this is not the huge earthquake that seismologists say is long overdue in Tokyo. That is expected to ripple up from Shizuoka in the south. Tokyo sits above two faultlines and near another. Just south-west of the city, the Philippine Sea plate dives down under the Eurasian continental plate; right under the city, the Pacific plate dives under that.
Early estimates of damage from this earthquake are necessarily crude. The 6.8-magnitude Hanshin earthquake that struck Kobe in 1995 killed 6,400. The cost was put at Y10 trillion ($100 billion). Industrial production dipped only briefly. The stockmarket fell by 8% in the week following the quake, but rose later. Tohoku, the north-east region of Honshu island where today's quake struck hardest, accounts for 8% of the country's GDP. The area is less densely populated than around Kobe, and less industrial. The quake, though very much larger, may prove less damaging, though horrific enough for all that.
See also our correspondents' account of the reaction to the earthquake in Tokyo.