| 11.1°C Dublin

What caused killer quake?

The Caribbean is riddled with a complex network of tectonic fault lines resulting from the movement of the Caribbean plate.

It is slipping eastwards at a rate of about 2cm a year, relative to the vast North American plate to the north.

The boundary of these two tectonic plates lies off the north coast of Haiti, but there are several fault-line systems to the south that cut across the country from east to west.

It was the sudden strike-slip movement of one of these fault lines -- the Enriquillo-Plantain Garden fault zone -- that led to the disaster.

Scientists calculate that the epicentre of the earthquake, which measured seven on the Richter scale, was approximately nine miles south-west of Haiti's capital, Port-au-Prince.

The point beneath the Earth's surface where the rupture began -- its hypocentre -- was just six miles away, making it a relatively shallow shock.

"Closeness to the surface is a major factor contributing to the severity of ground shaking" said planetary scientist David Rothery.

Experts warned that earthquakes of this size always have aftershocks that can last for many weeks.


Privacy