SURVIVING THE EARTHQUAKE

Surviving the Earthquake- Haiti 2010



Surviving the Earthquake- Haiti 2010

Haiti A Poor Nation

Haiti is the poorest country in the Western Hemisphere, and is ranked 149th of 182 countries on the Human Development Index. The Australian government's travel advisory site had previously expressed concerns that Haitian emergency services would be unable to cope in the event of a major disaster, and the country is considered "economically vulnerable" by the Food and Agriculture Organization. It is no stranger to natural disasters; in addition to earthquakes, it has been struck frequently by cyclones, which have caused flooding and widespread damage. The most recent cyclones to hit the island prior to the earthquake were Tropical Storm Fay and Hurricanes Gustav, Hanna and Ike, all in the summer of 2008, causing nearly 800 deaths. (Watkins, pp5-7)

The Day Of The Earthquake

The magnitude 7.0 Mw earthquake occurred inland, on 12 January 2010 at 16:53 UTC-5, approximately 25 kilometres (16 mi) WSW from Port-au-Prince at a depth of 13 kilometres (8.1 mi) on the Enriquillo-Plantain Garden fault system. Strong shaking associated with intensity IX on the Modified Mercalli scale (MM) was recorded in Port-au-Prince and its suburbs. It was also felt in several surrounding countries and regions, including Cuba (MM III in Guantánamo), Jamaica (MM II in Kingston), Venezuela (MM II in Caracas), Puerto Rico (MM II-III in San Juan), and the bordering Dominican Republic (MM III in Santo Domingo). According to estimates from the USGS, approximately 3.5 million people lived in the area that experienced shaking intensity of MM VII to X, a range that can cause moderate to very heavy damage even to earthquake-resistant structures. (Roth, pp 2-5)

The quake occurred in the vicinity of the northern boundary where the Caribbean tectonic plate shifts eastwards by about 20 millimetres (0.79 in) per year in relation to the North American plate. The strike-slip fault system in the region has two branches in Haiti, the Septentrional-Oriente fault in the north and the Enriquillo-Plaintain Garden fault in the south; both its location and focal mechanism suggest that the January 2010 quake was caused by a rupture of the Enriquillo-Plaintain Garden fault, which had been locked for 250 years, gathering stress. The rupture was roughly 65 kilometres (40 mi) long with mean slip of 1.8 metres (5.9 ft). Preliminary analysis of the slip distribution found amplitudes of up to about 4 metres (13 ft) using ground motion records from all over the world. (Harris, pp1-4)

A 2007 earthquake hazard study by C. DeMets and M. Wiggins-Grandison noted that the Enriquillo-Plantain Garden fault zone could be at the end of its seismic cycle and concluded that a worst-case forecast would involve a 7.2 Mw earthquake, similar in size to the 1692 Jamaica earthquake. Paul Mann and a group including the 2006 study team presented a hazard assessment of the Enriquillo-Plantain Garden fault system to the 18th Caribbean Geologic Conference in March 2008, noting the large strain; the team recommended "high priority" historical geologic rupture studies, as the fault was fully ...