Earthquake and Urbanization: Two lethal enemies

The recent earthquake in Chile has once again rattled us.We are still to reconcile with the massive death and destruction that happened in Haiti, and the one that preceded in the Sichuan region of China, both killing almost a million people.

 As death tolls and the agonies associated with earthquakes [food riots, displacement of income, spread of diseases and epidemics] once again stagger the human mind, there is a tendency to ascribe the lethality of earthquakes and the damage they bring as something very natural. It would be wrong to associate earthquakes and death as something corollary to each other, however, usually, we associate earthquakes as harbingers of death and destruction.

 The cause of earthquakes is best explained by the “Theory of Plate Tectonics”, largely developed since the 1960s.The earth’s crust ,divided in 7 major crustal plates that slide constantly, creeping along at about the speed of fingernail growth. When the plates strike each other, stress builds up on the fault line.Once the stress reaches the threshold, the fault line ruptures, resulting in earthquakes. It might take a year or two, or some centuries to result in an earthquake measuring beyond 6 on the Richter scale.On a strike-slip fault, of the type that ruptured in Haiti, it had not ruptured for more than 200 years.

Millions of earthquakes go undetected because they occur in remote areas, mostly under the sea, or have very small magnitudes.Earthquakes with magnitude larger than 7.0 cause heavy damage when they strike major mega-cities, like the one that happened in Port-au-Prince [in Haiti], a catastrophe that is certain to be repeated somewhere and the recent one in Chile has once again made our fears real.

Earthquakes are stress releasing mechanisms associated with  formation of the earth’s landforms. They are something very old, as old as the formation of earth, and the birth of cities and urban agglomerations are a new phenomena. It is the marriage of the “old” and the “new”  that makes earthquakes lethal for humanity.

 Beijing was the only city in the early 18th century with more than a million population. Now there are 381 urban areas with at least 1 million inhabitants. Urbanization crossed a threshold last year when, for the first time, more people lived in city settings than rural ones.

In case of India, with the growth of urbanization, we have 35 million plus cities.India has been divided into five zones [1 to 5], with respect to severity of earthquakes and majority of these cities lie in the high risk zone. Of these, Zone 5[the entire Himalayan belt and cities surrounding it] is seismically the most active, where earthquakes of magnitude 8 or more could occur. 

The Himalayan mountain range is the outcome of the collision of Indian and Eurasian plates,moving against each other at an estimated rate of about 5 cm/year.In a short span of 53 years,four great earthquakes [1897 Assam,1905 Kangra,1934 Bihar-Nepal and 1950 Assam] have taken place in this belt.

A recurring occurence of earthquakes of small and big intensities,in the entire Himalayan belt suggests that slippage is continuous, implying future great earthquakes in the unruptured parts of the Himalayan front. Major uncertainties remain about the recurrence interval of great earthquakes.The next victim may be Delhi or Katmandu or Assam or Dhaka, the list is endless.

The exceptional occurrence of the Latur earthquake [Killari], Maharashtra, of 1993, one of the most devastating SCR[Stable Continental Region] earthquake, its epicentre in a region considered as aseismic [Zone 1, according to Indian seismic classification]. The Latur earthquake testifies the point that no regions are safe and the division of regions into seismic or aseismic only creates a false sense of security.The Latur earthquake took place in a rural setting costing over 10,000 lives. The impact could have been incalculable if the event happened in Mumbai or Pune.

Recent experiences indicates that we might experience event like this every 10 years. In many vulnerable cities, people are effectively stacked on top of one another in buildings designed as if earthquakes don’t happen. It is not the tremor that kills people in an earthquake but the buildings, routinely constructed on the cheap, faulty designs,overseen by corrupt inspectors. The difference between life and death is often a matter of how much sand went into the cement or how much steel into a supporting column. 

Earthquakes might be viewed as acts of God, but their lethality is often a function of masonry. The lives that perished in the Bhuj [Gujarat] earthquake is a tale of the faulty engineering and corruption that resulted new buildings getting crumbled like sand. Whenever earthquakes happened in the major cities, buildings have acted like “weapons of mass destructions”.

With the world witnessing a steady urbanization in the next half-century and the planet adding an estimated 5 billion people with a billion housing units,we cannot be complacent to the fact that there is a massive amount of infrastructure built without earthquakes in mind.In spite of the warnings of possible earthquakes sounded by seismologists, people tend to be complacent about earthquakes that are yet to happen. In such a scenario, the question is whether those people will live?

Another related effect of earthquakes are “Tsunamis”, the largest ever that killed more than 227,000 people in 14 countries along the Indian Ocean[estimated to have released more energy than 20,000 atomic bombs].With tourism developing at a rapid phase, more and more people have the probability of coming under the wrath of tsunamis in coming years. The recent earthquake in Chile has sounded alarm bells for people living in coastal areas and vulnerable islands, majority of which are being evacuated.

As the world battles with a phenomena that is nearly unpredictable and the United Nations and other world bodies spend millions of dollars looking for banned nuclear, biological and chemical weapons, it would be beneficial to come up with solutions that can save millions of lives from the after effects of earthquakes and tsunamis. Perhaps the United Nation can develop a building inspection program that does away with the faulty practices and corruption, inherent in the real estates in all the countries. A standardized model of earth-quake engineering and a common curriculum of “disaster preparedness” introduced in schools and colleges across the globe, so that we have a pool of people ready to deal with contingencies. Its time for the leaders of the world to bring their heads together, so that all the countries function as one unit in dealing with such catastrophes.