The earthquake that happened in Chile, which had a magnitude of 8.8, actually occured in an offshore zone that was was under increased stress. This was caused by an earthquake in 1960 that had a magnitude of 9.5. The earthqake occured at the boundary between the Nazca and South American plates and was triggered when the Nazca plate subducted and thrust under the South American plate. These plates converge 80 mm per year which is one of the fastest rates on the planet. Scientists calculated the 1960 earthquake and recored that it was the largest recorded earthquake in history, and it caused a large stress increase on the ends of the current rupture. The Chili earthquake had a longer rupture zone than the Haiti earthquake, however Haiti experienced more damage, and this is because Chile is more prepared for earthquakes than Haiti, and the coast of Chile has a history of large earthquakes.
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