The danger of powerful earthquake, Find a way to save the metropolis

Natural disasters bring long-term and short-term suffering to people. There are many kinds of disasters happening all over the world. Natural disasters include floods, droughts, cyclones, floods, erosions, earthquakes, etc. Among them, earthquakes are very serious natural disasters.

Most natural disasters can be known in advance, but no one can know until a natural disaster like an earthquake occurs. Since people cannot know in advance when an earthquake will occur, they cannot take any measures to avoid or cope with its damage. As a result, if there is a high-magnitude earthquake in an area, there is a huge loss of life and property in the concerned area. A major earthquake occurred in Indonesia a few days ago. Before that, there was a huge loss of life and property in the earthquake in Turkey.

Earthquake is the name of such a horror, which can turn a town into ruins in a matter of seconds. Earthquakes usually last from a few seconds to a minute or two. Once an earthquake occurs in an area, several earthquakes may occur in the same location or in nearby areas. It is called 'after shock'. 'Epicenter' is very important in case of earthquakes. The 'epicenter' is where the earthquake originates. Earthquakes of moderate or severe magnitude are felt every moment around the world. The website of the United States Geological Survey regularly publishes information on earthquakes of various magnitudes occurring in different parts of the world.

A long time ago, all the land masses of the world were together. The Earth's surface is composed of several rigid plates that have gradually drifted apart. Scientists call these plates tectonic plates. The cracks between two tectonic plates are called fault lines. Fault lines play a major role in earthquakes. Earthquakes occur when two plates collide along a fault line. Basically, tectonic plates are connected side by side with each other. Energy is created when they collide for some reason. This energy spreads as seismic waves. If the wave is strong, it reaches the Earth's surface and shakes the ground. This tremor is basically an earthquake. The whole world is divided into seven major plates. These are the African Plate, Eurasia Plate, Antarctic Plate, Indo-Australian Plate, North American Plate, Pacific Plate and South American Plate. In Bangladesh earthquake refers to earthquakes in Bangladesh and adjacent areas.

There are several active fault zones in Bangladesh. These are the Bogra fault area, Rajshahi's Tanor fault, Tripura fault, Sitakunda Teknaf fault, Haluaghat fault, Daoki fault, Dubri fault, Chittagong fault, Shahjibazar fault (partial-Dawki fault) of Sylhet and Rangamati fault area in Barakal of Rangamati. Bangladesh lies between the Indian, Eurasian and Burma (Myanmar) tectonic plates. Both the Indian and Eurasian plates (since 1934) have been stuck in the foothills of the Himalayas for a long time, waiting for major movements or earthquakes.

A study by Lemont Doherty Earth Observatory geologist at Columbia University in the United States (July 2016) revealed that the pressure of the tectonic plate under Bangladesh has been accumulating for the past 400 years. When this pressure is released, the magnitude of the earthquake can be 8.2 on Richter scale. It can even reach 9 on the Richter scale. According to Mehdi Ahmed Ansari, Founder Secretary General of Bangladesh Earthquake Society and Professor of the Civil Engineering Department of BUET, the return period of an earthquake is 150-250 years. In 1762, an earthquake of magnitude 8 occurred in Arakan and Chittagong region, which has not yet returned as a cycle. Then there was an earthquake in 1885 (the Madhupur Fault Earthquake, also known as the Bengal Earthquake). No one knows when such a 150-250 year cycle will be available. But the system is the same, we must be prepared; any major post-earthquake rescue operation requires extensive preparation.

Three districts of Chittagong Hill Tracts and Jaintapur area of Sylhet are at risk of severe earthquakes in the country. All areas are located within at least 100 km from Dhaka. If there is an earthquake of magnitude 7 to 8, it can cause a major disaster for Dhaka. Housing areas have been developed by filling the reservoirs in the extended part of the city. During an earthquake, soft soil and soil in filled areas increase the magnitude of earthquake vibrations and the soil may liquefy. As a result, the impact of earthquake damage can increase. In the construction of buildings in Dhaka city, it is necessary to analyze the quality of the soil and build according to the 'Bangladesh Building Code' with skilled geotechnical and structural engineers.

Natural disasters are not really a matter of a particular region or a particular time. Earthquakes and other natural disasters can occur in any region at any time. There are many types of harmful effects of natural disasters. Disasters are causing massive damage to infrastructure along with loss of human lives. We cannot prevent natural calamities, especially earthquakes, floods, droughts. However, if you try and take effective measures, it is possible to control the amount of damage caused by natural disasters. Especially during the construction of infrastructure, if they are made disaster-resistant, the amount of damage can be greatly reduced. If we can build disaster-resilient infrastructure, it may be possible to protect infrastructure during most disasters. If we do not keep disaster resilience in mind while building infrastructure, our losses will be high. By building disaster-resilient infrastructure, we can protect people from disasters and also reduce financial losses relatively. The cost of building disaster-resilient infrastructure is not much higher than the cost of normal construction.

Earthquakes and other natural calamities will be given priority here because Bangladesh is a very disaster-prone region. It is the world's largest delta region which is located in the coastal region. As a result, naturally, natural disasters are our daily companions. We cannot be completely free from natural disasters even if we want to. But if you try, it is possible to reduce the damage caused by natural disasters and limit it to a tolerable level. The harmful effects of climate change are being observed globally. Although Bangladesh is not responsible for climate change, Bangladesh is the most affected by its effects. Southern districts of the country are suffering major infrastructure damage due to floods. Saltwater intrusion from the sea is destroying the productivity of agricultural land. Various departments are working to build disaster-resilient infrastructure. They have their own plans. I think these departments should develop a consistent resource management system. In case of any kind of disaster, where and what kind of damage can be caused and how that damage can be limited, should be worked on continuously. When a cyclone or flood is likely to occur in an area, we are getting the forecast in advance. Then we can decide how quickly post-disaster damage can be overcome. Disaster management issues should be included in the design manual.

The government is handling the issue of disaster management very efficiently. Bangladesh's disaster management is being appreciated globally. Our disaster management is better than many neighbouring countries. Bangladesh has formulated an international standard Standing Order of Disaster (SOD). This SOD clearly states the responsibilities of any department during and after a disaster. Before the occurrence of a natural disaster, during the disaster and after the disaster, there are committees related to who has what responsibility. This committee extends to the lowest level. Due to the effective disaster management of the government, the number of natural calamities and loss of life has been greatly reduced. In our country in 1970, there was a terrible cyclone in the coastal region. Then there was a severe cyclone in 1991. As many people and property were destroyed then, cyclones or floods do not kill as many people now. A few days ago, a cyclone called Midhili caused the loss of property and infrastructure damage to the same extent as before. Although the field crops were damaged. Early warning of any natural calamity results in relatively less damage.

Another natural disaster we are concerned about is landslides. Sometimes there are reports of loss of life and property due to landslides in Chittagong region. If warnings about landslides can be spread, then this problem can be eliminated to a large extent. I am conducting research with a professor at the University of Quebec. The soil in their country is called sensitive clay soil. Sensitive clay soils cause extensive damage due to landslides. The soil of our country is clay soil. We can build pre-cautionary measures here if we try. If that is done, the risk of landslides will be greatly reduced.

We cannot prevent the natural disasters that are happening in our country, but disaster damage can be limited to a tolerable level. The government is managing the disaster very logically and efficiently. In the past, if any natural disaster occurred in the country, the amount of damage would be severe. Even though it is a terrible natural disaster at present, the amount of damage is tolerable. We have to play a more effective role in order to limit the damage caused by natural disasters in the future. Now, during the construction of infrastructure, by collecting information about why the road was broken earlier, measures are being taken during the construction of the new road, so that the previous situation cannot be created in the future. A Bengali poem about disaster comes to mind, in translation it will be like this: 'Adaptive steps must be taken to deal with natural disasters / The world will move forward on the path of adaptation by forgetting worries / There will be no regrets in disaster mitigation.'

So now it is the time to conduct mass awareness programs about earthquakes, to inform people. Only proper preparation can reduce the massive damage caused by earthquakes.

Author: Founder President, Save People for Earthquake and Environment Disasters (SPEED) and geotechnical specialist.

Transcribe: M A Khaleque