Earthquake devastation: Lessons from Haiti and Chile
Haiti earthquake devastation.
WHAT are the reasons that increase the volume of damage in an earthquake? Is it possible to reduce this intensity of damages? Is it only the degree of magnitude (Richter scale) that determines the intensity of damages in an earthquake? These are queries from the people who have not usually have much idea about the seismology or plate tectonics. In fact most people when they hear any news regarding earthquake immediately look for reports on Richter scale magnitude of earthquake. But if we look at the recent earthquakes in Chile and Haiti, the Richter scale magnitude appears as not the major factor that contributed to the damages. Chile earthquake was far stronger (8.8 magnitude) than the Haiti earthquake (7.0 magnitude) yet the death toll and other damages in Haiti happened to be higher than Chile. What was the reason behind ? To get an idea we have to understand first the factors that determine the potentiality of hazard in an earthquake. This potentiality largely depends on some natural and social factors. Natural factors are, Geology, Peak Ground Acceleration (how hard the earth shakes in a given geographic area), Active Faults (fault that has moved recently), distance of the fault from the epicentre, its proximity to habitats, distance of the underground point from where the quake originates (focus or hypocenter) from inhabitants, and time when it happens. Social factors are economy of a country, compliance of building codes, per capita number of seismologists and earthquake engineers, evacuation plan, presence of integrated management system and previous experience of handling earthquake catastrophe. From the recent earthquakes in Chile and Haiti, we could find a very good instance of how natural and social factors contributed to increasing or reducing the devastation. Chile has a better economy and is better prepared with strict building codes, robust emergency response and a long history of handling seismic catastrophes. Frequent seismic actions are common in Chile. The country experienced the strongest earthquake on record in 1960, and recent quake was the nation's third of over 8.7 magnitude. In contrast Haiti having very weak economy, there is no building code and they don't have previous practical experience of handling quake devastation because the last major earthquake that hit Haiti's capital Port-au-Prince was 250 years ago. In Chile there are thousands of earthquake resistant housing structures but in Haiti only a few structures are earthquake resistant. Consequently they paid a lot. Haitian government reported that an estimated 230,000 people had died, 300,000 had been injured and 1,000,000 made homeless making it one of the worst natural disasters in modern history. Chile's quake was centered offshore, an estimated 21 miles (34 kilometers) underground in a relatively unpopulated area while Haiti's quake struck closer to the surface -- about 8 miles (13 kilometers) -- and right on the edge of Port-au-Prince. This proximity of epicentre to the surface amplified the vibrations and caused far more damage to densely-packed urban areas near the Haitian capital. Apart from Chile there is also a best example of Japan, how they minimized the fear of earthquake hazatd. Tectonically Japan is located on the Pacific seismic and volcanic rim and lies over four tectonic plates which made the country very prone to earthquake. But the country progressively minimized the risk of earthquake devastation which is a good learning example for others. According to Global Earthquake Safety Initiatives (GESI) per capita risk causalities to school children is very minimal in Japan compared to other countries. For example, whereas the possibility of causalities is 400 in Kathmandu, 80 in San Salvador, it is only 3 in Tokyo and 1 in Kobe. A Purdue University geophysicist Eric Calais studying the Haiti earthquake said, "Earthquakes don't kill -- they don't create damage -- if there's nothing to damage". Though among the natural disasters earthquake is one of the worst that can't be predicted and might cause massive devastation in a few seconds and humans have no power of control it, but they can minimize the intensity of damage. In this context Haiti and Chile earthquakes are good learning examples for us to develop, review and update our own earthquake preparedness to save the lives and properties of our people.
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