Indigenous technologies are much more convenient compared to the modern imported ones and can be used for building temporary shelters
Taiwan was struck by an earthquake of magnitude 7.2 on the Ritcher scale last Wednesday morning, March 3, 2023 that led to the demise of 10 people and the injury of more than 700 persons. Many multi-storeyed buildings have tilted to a precarious position warranting for their immediate demolition. The damage has been noticed mostly in the city of Hualiyen.
Nepal had experienced earthquakes in Jajarkot district which measured around 6.4 in magnitude on November 3 last year. In the earthquake, 158 people perished with more than 345 injuries. More than 40,000 families have been affected and are staying in temporary shelters.
An earthquake is the shaking of the ground which otherwise is firm and still. As a result, the buildings standing on the ground are affected, some even to the extent of collapsing, killing and injuring many people. The shaking occurs due to the land masses rubbing against each other on either side of the gaps or the faults that rest on the mobile tectonic plates forming the upper crust or the earth which break after converging towards each other. The point where such an event occurs is known as the hypocentre and its corresponding point on the ground is known as the epicentre. The nearer the epicentre the more the damage. The epicentre in the Taiwan earthquake was 11 kilometers away.
It produces primary waves which are the first to be felt. It is followed by the more devastating secondary waves, which hit after about 15 seconds if the epicentre is near and 22 if it is far. In developed countries like Japan, more sensitive objects like bullet trains are stopped immediately after the arrival of the primary wave to prevent the likely damage due to the damaging waves that follow. The most devastating are, however, the surface waves which are the last to arrive at the spot.
The earthquake is measured on the Richter scale. The succeeding scale is 32 times the preceding one. It means that an earthquake of 2 is 32 times larger in intensity compared to one on the Ritcher scale. The explosive that is used in road construction is said to have a magnitude of about 1 and its energy is about 2 million joules. The energy of the Taiwan earthquake was equivalent to 32 bombs dropped on Hiroshima.
Several commonalities and contrasts can be seen in the earthquakes that have occurred in Taiwan and Nepal. Starting with the similarities, in Nepal, the Indian and Tibetan plates are responsible for the arrival of the earthquake. In Taiwan, it is due to the convergence of the Philippine sea plate and Eurasian plate towards its east. Similarities, however, end here and what follow are the striking dissimilarities.
The dissimilarities are marked by the difference in the number of deaths and injuries. Whilst only 10 persons died in the 7.2 magnitude earthquake in Taiwan, 158 persons died in the 6.4 earthquake which was almost 30 times smaller. The buildings affected were also small in the case of Taiwan against the stark contrast of 40,000 of them in Jajarkot and adjoining Rukum district.
The other dissimilarity is the preparedness that has been launched in either country. In Taiwan, 2,400 people died in the 1999 Chi Earthquake, which measured 7.7 in magnitude, with injury to 10,000 persons. But they waged such a preparedness campaign that the deaths were reduced to a mere 10 as could be seen in the Wednesday earthquake.
On July 29,1980, some 200 people had died in the Bajhang earthquake. But the preparedness was not conducted properly with the result that many buildings collapsed in the twin earthquakes of magnitude 5.3 and 6.4 that occurred in October last year. Worse still, this area has not experienced a mega earthquake since 1505, and seismologists have been warning that enough energy has accumulated to trigger a more than 8 magnitude earthquake in the future. Parts of western Nepal and even northern India could be flattened in case of such a calamity.
The other contrast is in the area of response. In Jajarkot, many have not received even temporary shelter. A few shelters using galvanized iron sheets, commonly known as zinc sheets, have been constructed, but they are biting cold in winter and boilingly hot in summer. A study made by Rita Thapa et al, 2015 has suggested that the temperature should not drop below 11° Centigrade in winter and 30° in summer for comfortable living.
But it can be prevented through the use of indigenous and cost-effective means. In Jajarkot, a temporary shelter has been constructed by this columnist using bamboo and plastic sheet with the help of the Nepal Academy of Science and Technology, Lumbini Academy of Science and Technology and Kantipur International Engineering College. Ward No 4, Githakot of Sani Veri Rural Municipality uses this shelter as its office. The construction has employed bamboo mesh with a 2 inch air gap on both the walls and the roofs and are plastered with mud on the inside and outside. The temperature of the interior was between 17 and 22°C at a time when it was 13 and 34 outside at night and day time on March 20-21.
What is more interesting is that the retrofitting carried out by the columnist using such a technology with the initiation of the Community Self Reliance Centre, Nepal in the existing temporary shelter made of zinc sheets in Nulgadh, Jajarkot recorded again similar temperatures as mentioned above.
Of course, more measurements have to be taken to come to a substantive conclusion, but it has indicated that indigenous technologies are much more convenient compared to the modern imported ones. These technologies can certainly be used for building temporary shelters as they are used for permanent shelters in Madhesh. In fact, the retrofitting of existing zinc temporary shelters should be carried out to make the living of the earthquake victims comfortable.
Prof. Pokharel, Ph.D. is former VC, Nepal Academy of Science and Technology
