liquefaction

The Mw 7.0 destructive earthquake that struck the Republic of Haiti on January 12, 2010 was one of the deadliest of the last century in the region. What has been concluded after a field study during the period from 16th to 22nd of January 2010 is that this event is mostly a man-made natural disaster. This is due to the very adverse social, political and economic conditions that existed before the earthquake that greatly contributed to the lack of any building-construction code and control of land use and the lack of any governmental – public services during the post-earthquake emergency. The primary effects of the earthquake were worsened due to the inability or absence of any preparedness for search and rescue and help the victims. The frozen response of the structures to the seismic event, observed during the field trip, gave valuable information about the ground motion, since instrumental records were unavailable. The response of a fence functioning as a primitive seismoscope was analyzed, resulting to an effective ground horizontal acceleration of about 0.6 to 0.7 g. Similarities between Haitian structures and their response with instrumented cases in other regions, resulted in the acceptance of a 1.0 g vertical acceleration for the site. Finally, the detailed investigation of the whole liquefaction phenomenon at the site, documented that this is starting with ejection of sand and water, before the large ground displacements take place and continues after the strong phase of the ground motion.