Somewhat offbeat advice has come in from that storehouse of unusual ideas, India’s ministry of environment and forests. It has counselled the building of bamboo-based houses in earthquake-prone areas. This might, at first glance, sound odd. This is the 21st century, after all, and many technologies are now available for quake-proofing concrete structures. However, the advice is fundamentally sound. Bamboo is already used to construct houses, and with good results, in several countries in seismically active zones. Japan, which has recently had a series of ruinous tremors, is generally believed to have escaped with a relatively minor human toll thanks to its perfection of quake-resistant construction technologies, some of them decidedly low-tech. Even more quake-susceptible countries like Costa Rica and Colombia have traditionally relied on bamboo to keep the devastation to the minimum.
Over a billion people around the world live in houses that have used bamboo liberally in their construction. Where bamboo does better than many other commonly used construction materials, including steel, is in its resilience and elasticity — which enables it to sway back and forth without breaking when the earth trembles. Of course, it is a relatively cheap, renewable and environment-friendly material. It is generally accounted to be the fastest-growing of plants; it can regenerate quickly after it is harvested; and it can thrive even in degraded lands. In India, over nine million hectares are already under bamboo. It is, therefore, unfortunate that the use of bamboo as a building material has not spread — except in the Northeast, where people prefer to build bamboo houses in low-lying, inundation-prone areas. Yet much of the rest of India’s landmass is prone to earthquakes. Most of the Himalayas, a geologically young and fragile mountain range, falls in the highest seismicity category, Zone V, where tremors with a magnitude of over seven on the Richter scale are fairly usual. Large areas fall also in Zones IV, III and II, with earthquake risks that should not be ignored. Notably, no part of India is in Zone I, which is deemed relatively risk-free. And, unlike most other natural disasters – floods, cyclones and droughts – which can at least be foreseen if not averted, earthquakes can neither be predicted nor prevented. The only practical way to cope with them is to plan beforehand how to mitigate any damage they may cause. The development and promotion of modern bamboo-based house construction technologies can, therefore, help lessen the potential destruction due to tremors in the highly vulnerable Himalayas, and across other regions.
In areas like Uttarakhand, which fall in the highest-risk zone and are increasingly densely populated, bamboo-based housing is, in fact, urgently needed to avert the possibility of large-scale casualties. It is worth recalling that most of the loss of life in Uttarkashi in the 1991 earthquake (which measured seven on the Richter scale) was due to the fact that many houses were made of stones put together with mud; they could not bear the shock, and crumbled. Had the houses been made of bamboo, instead of stones, the losses would have been far lower. Experiments conducted by the Bangalore-based Indian Plywood Industries Research and Training Institute have now shown that bamboo-based houses can easily withstand shocks with a magnitude of seven on the Richter scale without falling apart. The further refinement of bamboo-based construction technology, and the encouragement of its spread in areas most in danger of tremors, is overdue.