CHILE'S earthquake was many times more powerful than the one that devastated Haiti earlier this year but caused only a small fraction of the casualties, thanks to geological luck and the country's preparation for such a disaster.

Saturday's 8.8-magnitude quake was a 'megathrust' which unleashed about 50 gigatons of energy, but it was centred offshore and about 21 miles underground, dissipating its force by the time it reached towns and cities.

In contrast, the 7-magnitude quake that struck Port-au-Prince on Jan 12 was much shallower — about eight miles deep — and right on the edge of a city where three million people lived.

Eight Haitian towns and cities suffered 'violent' to 'extreme' shaking, whereas Chilean urban areas did not suffer more than 'severe' shaking still horrible, but a let-off.

The other reason Chile was counting its dead in the hundreds rather than hundreds of thousand was that this is one of South America's richest, best-organised countries. It has long experience of dealing with earthquakes.

Seismic activity is common along its Andean ridge. In 1960 it suffered one of the strongest quakes on record. Saturday's was the third with a magnitude greater than 8.7.

Homes and offices are built to sway with seismic waves rather than resist them. “When you look at the architecture in Chile, you see buildings that have damage, but not the complete pancaking that you've got in Haiti,” said Cameron Sinclair, executive director of Architecture for Humanity.

Sinclair said Chilean architects have built thousands of low-income houses to be earthquake resistant. It is required by blueprints and building codes.

Even with damage estimated at $15bn-$30bn, and airports, motorways and bridges shut, the state responded swiftly.

“The fact that the president (Michelle Bachelet) was out giving minute-to-minute reports a few hours after the quake in the middle of the night gives you an indication of their disaster response,” said Sinclair.

— The Guardian, London