The Japanese earthquake in 2011 and some thoughts about its prediction
On the 11th of March 2011, there was a huge earthquake near Japan. Its magnitude was 9.0, and it created a destructive tsunami that registered higher than 10 meters tall in some places. The aftermath was catastrophic. Many people were killed, and many buildings were destroyed. However, the most interesting thing was that the Japanese were as ready as they could be. 90 seconds before the main push on Tokyo, there was an alert via TV and mobile phones. It saved many lives. There was also a tsunami warning 10-30 minutes before the actual flood, and thanks to that people were able to climb to higher places and get away from the shore. It became possible because of the warning system that connected with the net of sensors located near the shore. The speed of light is faster than the speed of seismic waves going at speeds of 4 km/sec, so the sensors received the signal from the ground and put it through to Tokyo on TV and warned everybody about the danger.
Some days before the main shock there were some foreshocks (small earthquakes) on the 9th of March with a magnitude of 7.2 and 6.0. Scientists had expected the strong earthquake in that region with a magnitude of 8.0, but not a 9. In other words, an earthquake with a magnitude of 9 is ten times stronger than of 8. The power of the Japan earthquake was as strong as 1000 nuclear bombs thrown on Hiroshima. Was it a unique unpredictable event or could it have been and should it have been predicted?
The final goal of seismologists is to predict earthquakes a couple of days in advance before the event. Modern forecasts of earthquakes are quite useless. To be a useful forecast, it should report when, where and how strong an earthquake would be and the probability of this event. The problem is we don't have such technology. We can only predict an earthquake in a wide area many years before the event. However, this is still unreliable. Its probability would be around 50%: it might occur or might not.
Nevertheless, I would like to give you a piece of advice. If you live in an area where small earthquakes happen, it's a good idea to be prepared for the strong ones because they will come eventually. You ought to think of moving to another area. It might be worth it.
Good luck and steady ground!