Although just a few weeks separated the Haiti and Chile earthquakes, scientists say the two disasters are unlikely to be linked.

While the sort of 8.8 magnitude quake that struck South America at the weekend is an annual event, the sort of magnitude 7 quake that hit Haiti was common - occurring somewhere in the world once a week.

Despite the speculation of some geologists, there is no hard evidence to link earthquakes that occur thousands of miles and several weeks apart, according to Prof John McCloskey, a geologist at the University of Ulster.