A field reconnaissance in Haiti by a five-member team with expertise in seismology and earthquake engineering has revealed a number of factors that led to catastrophic losses of life and property during the January 12, 2010, Mw 7. 0 earthquake. The field study was conducted from January 26 to February 3, 2010, and included investigations in Port-au-Prince and the heavily damaged communities to the west, including Léogâne, Grand Goâve, Petite Goâve, and Oliver. The magnitude 7. 0 earthquake that struck the Republic of Haiti on January 12, 2010, is among the most destructive earthquakes in recorded history. As of February 16, 2010, the death toll reported by the Government of Haiti exceeds 217, 000, with an additional 300, 000 people injured. More than 5 million people live in the area directly affected by the earthquake, and 1. 2 million people are now living in temporary shelters (United Nations, 2010). Five weeks after the earthquake, humanitarian relief agencies continue to be challenged by the scale of the disaster.