The destruction wrought by the 9.0 Sendai Earthquake and Tsunami is truly appalling. Untold lives have been lost. Thousands of square kilometres were obliterated by the water which swept up to 20km inland.
The death toll officially stands at 1,000-2,000 but it must really be much higher. One town alone reports 10,000 of its 23,000 residents missing while several cities with populations in the tens of thousands were subjected first to shaking, then tsunami, and finally fires.
There is still no comprehensive picture of the damage done to these cities and how much of their populations managed to escape before the tsunami hit. Some 500,000 people are in emergency shelters and power is out to 10% of homes in the country.
One 60 year old man was rescued from the roof of his house, which had been swept 15km out to sea. The tsunami caused damage as far away as Crescent City, California, where the harbour was wrecked and one spectator drowned.
Some coastal areas are now below sea-level while towns and rural areas remain submerged by stagnant tsunami water.
Amazing before and after shots of the tsunami damage.
Cooling problems have been reported at six nuclear reactors. One appears to have partially melted down and a hydrogen explosion blew away its outer containment building although the inner containment does not seem to have been breached and radiation release has been minimal. A second reactor appears to be on the verge of meltdown.
The most affected region is not near Japan’s economic heartland, nonetheless the economic cost will be huge. Estimates of physical damage run from US$100 billion to $1 trillion but it is impossible to really know. As we know from Christchurch there will be an immediate economic hit followed by increased activity due to the rebuilding.
However, the scale of this event means the insurance pay-outs and liquidation of Japanese savings to fund that rebuilding will affect the global economy. As capital is sent or repatriated to Japan less will be available to others, meaning investment and borrowing costs will rise. The yen should gain in value as it did after Kobe, while countries that have capital sucked out of them (possibly including New Zealand) will see their currencies fall. The hit to the global economy should also see a ‘flight to quality’, dampening demand for our dollar, which means higher returns for exports and higher prices for international commodities (oil, milk etc)
The quake has been upgraded to 9.0 on the Richter scale. That means it released about 2 exajoules of energy, which is 474 megatonnes, nearly five times the largest ever man-made explosion – the Tsar Bomba – and 11,000 times more powerful than the Christchurch earthquake.
Apparently, the maximum ground acceleration from the quake was a lot less than Chch2 (0.35g vs 2g), which meant buildings would have been less likely to be knocked over but shaking went on for five minutes and the repeated stressing would have created severe damage. The huge cracks in roads are evidence of that.
Japan moved around 8 feet closer to North America and moved downwards about 2 feet due to the movement of the plates. The means the Earth’s mass is now slightly more concentrated around its axis. Like an ice skater bringing here arms in to spin faster, conservation of angular momentum means the Earth’s spin has sped up making a day 1.6 milliseconds shorter. Interestingly (for certain values of ‘interesting), this actually makes a day closer to 24 hours long. See there are 86,400 seconds in 24 hours. The STI unit for seconds is set as 9,192,631,770 periods of the cesium atom and that hasn’t changed but, because events like this earthquake change the speed of Earth’s rotation, there were about 86,400.002 seconds in an average day prior to the quake. Now, it will be much closer to 86,400, possibly meaning fewer ‘leap seconds‘. Every geosynchronous satellite will also have to be moved slightly inwards.
There orbits will also have to be adjusted for the fact that the earthquake knocked the Earth’s axis off by 10cm.