cause
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Haiti is a country in the western hemisphere and is situated on the island of Hispaniola. Haiti is located on the boundary of the Caribbean and North American plates. On the 12th of January 2010 at 4:53pm local time, a magnitude 7 earthquake hit Haiti. This was due to movement along the conservative plate boundary that runs through Haiti and it was the strongest earthquake to hit the island nation in more than 200 years. The Caribbean and North American plates are always moving past each other, about 20mm a year. It is quite rare to have major earthquakes in this part of the world because the Caribbean plate is only a minor plate and it much smaller than other plates in the world. Both plates move in the same direction, but one moves faster than the other. The much larger North American plate moves westward relative to the Caribbean plate.
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There are
two major faults between the plates at this point: the Septentrional fault
system, which runs through northern Haiti, and the Enriquillo-Plaintain Garden
fault system in the south. Tectonic plates don’t always move smoothly
alongside each other and sometimes get stuck, creating friction. The earthquake
occurred as the built up tension from inside the crust was released. The
earthquake’s epicentre was 15km west of Haiti’s capital, Port-au-Prince, where
most people, businesses and services are situated. The system of faults hasn’t
caused any major earthquakes in recent decades although they are believed to
have been linked to some historical big earthquakes in 1860, 1770, 1761, 1751,
1684, 1673 and 1618. The depth of the earthquake was very low and this means
that the energy from the earthquake was released closer to the earth’s surface.
This resulted in more damage because the seismic waves have to travel a smaller
distance through the earth’s crust to reach the surface and therefore maintained
more of their energy.