HURRICANES AND POSSIBLY DEFORESTATION AS TRIGGERS FOR THE 2010 HAITI EARTHQUAKE

The January 12^th, 2010, M = 7.0 Haiti earthquake was one of the worst natural disasters of the past century. This devastating earthquake caused the death of more than 200,000 people, the injury of about 300,000 people, and left about two million people homeless. Just a year and a half prior to the earthquake, Haiti was subjected to another severe disaster, flooding induced by two hurricanes and two tropical storms (Fay, Gustav, Hanna and Ike). Both natural disasters results in death and destruction, but because their origins are very different, they are generally considered to be unrelated phenomena. We suggest a physical link between these two destructive events, in which the 2010 Haiti earthquake was triggered by rapid erosion induced by hurricane activity. The suggested denudation triggering mechanism is consistent with the initial vertical motion along an inclined fault surface of the earthquake. We show that rapid erosion and sediment transport from the earthquake’s epicenter area to the Port-au-Prince Bay occurring over the past century have removed a large enough load sufficient for changing the stress at the earthquake’s hypocenter above the earthquake triggering threshold (3 kPa). Haiti’s massive deforestation most likely contributed to the rapid erosion and the heavy tropical rains contribute to efficient sediment transport. The heavy rain poured during the 2008 hurricane season flushed the drainage system in the epicenter area and removed the last significant sediment load that triggered the 2010 Haiti earthquake.