subject: Haiti Earthquake - Lessons Learned For Reducing Risks [print this page] Haiti Earthquake - Lessons Learned For Reducing Risks
The epicenter was 15 miles southwest of the country's capital, Port-au-Prince, at a depth of 6.2 miles below the ground surface. The event occurred on the Enriquillo-Plantain Garden fault system in southern Haiti which is an east-west trending left-lateral strike slip fault. This fault system has not generated a major earthquake in recent decades although it may be the likely source of historical large earthquakes in 1860, 1770, 1761, 1751, 1684, 1673, and 1618. The earthquake was felt throughout Haiti, the Dominican Republic, southeastern Cuba, eastern Jamaica, and in parts of Puerto Rico and the Bahamas. However, because the earthquake source was shallow, the intensity of shaking was stronger and more localized at the region along the fault.
Casualties
There is no way of knowing the death toll or causalities (injuries and fatalities) after few weeks of such a catastrophic earthquake. However, the death toll rises up to 230,000 as of February 9th according to USA Today. One third of the Haiti's 9 million people needed emergency aid according to the International Federation of the Red Cross. Many hundred thousands are still homeless and sleeping in the streets. This put Haiti earthquake as one of the deadliest quakes in the last four decades. The latest of such catastrophic quakes was the May 12, 2008 magnitude 7.9 Sichuan earthquake in China which is considered to be the third deadliest quake. According to the US Geological Survey on Sichuan earthquake; at least 69,195 people killed, 374,177 injured and 18,392 missing and presumed dead. More than 45.5 million people in 10 provinces and regions were affected. At least 15 million people were evacuated from their homes and more than 5 million were left homeless.
Buildings Damage
Haiti is the poorest country in the western hemisphere with more than 80% of its population lives below the poverty line. The earthquake caused severe damage and destruction in the Port-au-Prince area which is densely populated. Haiti's President issued a desperate appeal for international aid following the earthquake stating that the tremor was catastrophic and is unimaginable, and that the Parliament, the tax office, schools, and hospitals have collapsed. Other collapsed or severely damaged buildings include the UN peacekeeping mission, the presidential palace, the national cathedral, and the main prison. Haiti most likely does not have a building code where substandard design, inadequate materials, and shoddy construction practices contributed to the collapse of buildings. Even newer construction has been developed to withstand the vertical loads of hurricanes but not the lateral loads of earthquakes. The load path, and the engineering design and connection detailing concepts for hurricanes and earthquakes are completely different. Many buildings collapsed just like pancakes as builders put the reinforced concrete roof on top of low-grade bricks, construction blocks, or thin columns. Other nonductile reinforced concrete buildings collapsed because builders or owners were trying to cut costs by skimping on cement, adding excessive water, and reducing the amount of reinforcing steel.
Lessons Learned
The situation would definitely be different if a similar earthquake hits the United States where structural engineers design buildings to resist earthquake lateral forces according to the current stringent building design codes. In the meantime, the local governments enforce good construction practices. However, there are still many lessons that can be learned from Haiti earthquake, the most important are:
Earthquake awareness should be in everyone's mind. Haitians did not experience a large earthquake since 1860 and it seems they did not even know that they live on or close to a historically active fault system. In the United States, raising public earthquake awareness in the Central and Eastern United States shall be encouraged for many active seismic regions that experienced large historical earthquakes and has the potential to develop moderate-to-large future earthquakes. Those regions include, but not limited to:
The New Madrid Seismic Zone in southeastern Missouri where three of the largest historical earthquakes of magnitude 7.0-8.0 occurred in the winter of 1811-1812; on December 16, 1811; on January 23, 1812; and on February 7, 1812. The region of potential impact due to earthquake activity in this zone is comprised of eight states: Alabama, Arkansas, Illinois, Indiana, Kentucky, Mississippi, Missouri, and Tennessee.
The Wabash Valley Seismic Zone along Illinois - Indiana border which is capable of generating a magnitude 7.1 earthquake that has the potential to impact three states: Illinois, Indiana, and Kentucky.
The Charleston Area in South Carolina that was hit on August 31, 1886 by one of the largest earthquakes in United States history.
