Why didn't scientists predict the earthquakes?

The earthquakes that caused devastation in Haiti on 12 January 2010 and in Chile on 27 February 2010 have reminded us once more of the tremendous destructive power of nature. The magnitude 7 Haiti earthquake is believed to have claimed 230,000 lives; in contrast current estimates of fatalities caused by the magnitude 8.8 Chilean earthquake stand at less than 1,000, even though the earthquake released 500 times the energy of the Haiti event. However, in both countries there has been destruction of homes, businesses and infrastructure on a huge scale, creating a human and economic catastrophe that will take years to recover from.