PEOPLE AND THEIR PROBLEMS

New Delhi, 21 October 2005

More Research Needed

GAPS IN PREDICTING EARTHQUAKES

By Radhakrishna Rao

There has been a phenomenal increase in the incidence of natural disasters in recent years in the form of tsunami, typhoon, tidal storm, hurricane and earthquake. The widespread death and destruction that followed the trail of deadly hurricane Katrina in New Orleans area of the United States and the massive earthquake in Pakistan and India have exposed the “achilles heel” of the administration in tackling the natural calamity on time and in an effective manner.

Notwithstanding the rapid advances in science and technology, many a time it becomes difficult to predict the natural calamity with a certain degree of precision and accuracy. And this is particularly true of earthquakes, which affect one part of the earth or the other with a recurring regularity. A recent earthquake that hit the Indonesian cities of Manado and North Malaku could not cause much damage because its epicenter was not on the ground. In contrast, the December2004 tsunami which had its epicenter in the depths of the ocean caused widespread havocs along the coastal stretches of South and South East Asia. Of course, prior to this tsunami, many researchers had hinted at the possibility of its occurrence. But unfortunately countries affected by the tsunami did not make any advance preparations to face the calamity.

All said and done, the science of earthquake prediction is far from perfect.  In fact, Dr.K.Kasturirangan, a former Chairman of the Indian Space Research Organisation (ISRO) and a Member of Parliament, had not long back expressed the view that “predictions for earthquakes have not reached the levels that can be reliable”.  Giving details, he had pointed out that “ground imaging allows us to identify the nature of motions of earth and its crustal dynamics. The plate tectonics can also be monitored at the minutest levels. Global Positioning System (GPS) satellites have helped detect differential movements in the Asian and European plates.  But when and where will be released is still in the realm of research”.

Clearly and apparently, interpretation and analysis of the data made available by earth observation and geo-detic satellites can help one to provide a picture of the “tectonic agony” leading to the occurrence of the earthquake. And a number of research teams in the US are busy working on perfecting the satellite-based techniques to scan in detail the results of the faults and deformation of a topographical feature so as to determine the possibility of an earthquake hitting a particular spot on the earth.

There was a speculation over a great earthquake hitting the young and seismically unstable Himalayan region of India. For instance, Roger Bilham of the University of California in the US has for long held the view that a great earthquake was “overdue” in the Himalayas. According to Bilham there were a dozen examples of regions across the Himalayan belt that could rupture and produce an earthquake with a magnitude of eight. On the other hand, R.N.Iyengar, a former Director of the Roorkee-based Central Building Research Institute (CBRI), says that as earthquakes cannot be predicted with certainty, as such reducing the risk to buildings and other constructions such as dams and bridges collapsing becomes critical. His argument is that “India must move to a system that estimates the probability of varying levels of ground movement occurring”.

The Earthquake Engineering and Vibration Research Centre (EECRC) at the Central Power Research Institute (CPRI), in Bangalore, is involved in developing techniques and strategies for an improved prediction of factors leading to the onset of the earthquake. The EECRC is well-equipped to offer consultancy in checking the design adequacy of structures for seismically active regions. In fact, in many parts of the world, high rise buildings have proved to be highly vulnerable to the devastative impact of earthquakes. For instance, in the January 2001 Gujarat earthquake, many high rise buildings in Ahmedabad city crumbled like nine pins.

Against this backdrop, experts have been driving home the point that damage to the human lives can be minimized by designing earthquake resistant buildings. However, there is no standard formula or commonly accepted strategy to design an earthquake proof building.  “No building is earthquake proof. But a properly engineered tall building should be able to withstand the maximum credible earthquake for its area without  collapse”, says R. Shankar Nair, Chairman of the Council on Tall Buildings and Urban Habitat at Chicago in the United States.

Studies carried out using GPS satellites show that the movement of the  Indian plate  in the north-eastward direction could be  a major cause of seismic activities in the Himalayan region, though South India was until recently thought  to be geologically stable region, it has often  been rocked by earthquakes of moderate intensity.  According to sources in Hyderabad-based National Geophysical Research Institute (NGRI), the tremors in South India is of tectonic  origin caused by the stresses accumulated in the crust of the earth due to the movement of the Indian plate.

In contrast to the tectonic earthquakes caused by the slippage along the fault line, volcanic earthquakes result from a sudden movement of liquid lava in the subterranean zones. Experts also warn that a carefully planned, simultaneous nuclear explosions can produce massive earthquakes in the far away places. Interestingly, in China intensive research has been carried out to find out the feasibility of using animals to forecast in earthquake.

China claims to have successfully predicted a massive earthquake in the thickly populated Lioming area in 1975 by observing changes in the animal behaviour and through fluctuation in the water levels before the quake. Of course, quake experts hold the view that pressure exerted by a huge water reservoir could trigger tectonic activities  and  the earthquakes that affected areas close to the Koyna reservoir in Maharashtra,  was believed to be  caused by the ‘hydrological factor’. However, earthquake researchers have their own doubts about the efficacy of using animals to predict seismic activities.

But as things stand now, it would need further research and observation to arrive at a comprehensive model that can effectively explain the phenomenon of earthquakes.  Indeed, a reliable earthquake model could go a long way towards saving millions of live and untold damages to the property.

 
(Copyright, India News and Feature Alliance)