Home ›› 29 Nov 2021 ›› Editorial
An earthquake registering 6.1 on the Richter Scale shook Dhaka, Chattogram and some other parts of the country early on Friday. The tremor was felt at around 5:45am. According to the United States Geological Survey (USGS), the epicentre of the earthquake was near Hakha, Chin State, Myanmar. It did not take one long to realise that the country narrowly escaped what could have been a major disaster. While the country escaped serious damages this time around, it may not be the case every time in the future. Experts believe that 70,000 or more buildings will collapse in the capital in case of an earthquake measuring seven on the Richter Scale. This will obviously lead to a major human tragedy the likes of which the country has rarely experienced.
We all remember the Rana Plaza tragedy of 2013 where an eight-storey commercial building collapsed. The death toll was more than a thousand. And it took three weeks to carry out the salvage operations. And we are talking about just one building here. If despite the wholehearted efforts of the fire brigade, soldiers and volunteers there were so many casualties we shudder to think about the cataclysmic effect an earthquake might have in Dhaka or other densely populated cities. Dhaka will be reduced to rubble and become literally uninhabitable if a major earthquake occurs anytime soon.
Are the authorities prepared to face that eventuality? All evidence suggests that the government’s preparedness is quite inadequate to face any earthquake.
Bangladesh has a long history of earthquakes. In 1762, a major earthquake caused the submergence of 150 square kilometers of land, and killed 500 people in Dhaka, then only a small town. Between 1850 and 1950, there have been another 7 significant earthquake in the region, ranging in magnitude from 7.0 to 8.7 on the Richter scale. Since the last significant earthquake, Bangladesh has changed quite significantly. The greater Dhaka area has a population of over 15 millions. A study conducted a few years ago predicted over 120,000 casualties in Dhaka due to a 7.5M earthquake. Unfortunately, it usually takes an earthquake disaster to shift the politics of seismic risk, through the catastrophic demonstration of the extreme vulnerability of buildings.
The threat of an earthquake is very real as Dhaka ranks among 20 cities vulnerable to earthquake.
According to experts, earthquakes and tremors depend on a lot of factors such as the proximity of the epicentre to Bangladesh. The country’s position is adjacent to the very active Himalayan front in the north and Burma deformation front in the east expose it to strong shaking from a variety of earthquake sources that can produce tremors of magnitude 8 or greater. There are epicentres very close to Bangladesh so this is a high-risk area. It also depends on the proneness of a certain area to earthquake damage. The more the earth shakes, the more destruction there will be. Then there’s the population density which is extremely high. There’s a lack of education, awareness and preventive measures. Urban planning is poor, there aren’t open spaces to seek shelter in, and hospitals are ill-equipped. All these factors combined heighten the risk. Dhaka is one of the riskiest cities for earthquakes in the world.
The earthquake record suggests that since 1900 more than 100 moderate to large earthquakes have occurred in Bangladesh, out of which more than 65 occurred after 1960. This increase in earthquake activity is an indication of fresh tectonic activity or propagation of fractures from the adjacent seismic zones. The present generation of people in Bangladesh hasn’t witnessed any major earthquake. As a result, the population has been generally complacent about the risk of earthquakes
Dhaka, located in the central region of Bangladesh, could be affected by a serious earthquake as there are active faults near the city. This was realized during the 19 December 2001 magnitude 4+ Dhaka earthquake that caused panic among many city residents. The epicentre was very close to Dhaka city. The location of a probable earthquake source so near Dhaka with the probable serious earthquake magnitude needs to be further investigated.
As stated earlier, people in general lack knowledge about earthquakes and have little idea about they have to do during earthquake. Reports show that a significant number of the skyscrapers of the Dhaka City are unplanned and foundations of the majority of buildings are sub-standard. Dhaka in particular and the urban areas in general are spreading at a rapid and unplanned rate. This obviously leads to vulnerability to seismic events because service delivery is not keeping pace with the growth.
Ground rupture is the main result of an earthquake strike. Shaking of ground causes severe damage to the buildings or other structures on the ground including houses etc. Shaking of ground at a particular place depends upon the distance of that place from the epicentre. Severe shaking of ground causes destruction of all the buildings of a city and many people die by getting buried in the building materials. It can’t be avoided because earthquakes strike a place all of a sudden. So, this shaking of ground compels construction engineering to develop buildings which are resistive to the strikes of earthquakes.
Earthquakes cause landslides and may claim many lives at the effected zone. Earthquakes cause breakdown of electrical or gas supply lines which may lead to incidents of fires. Waterlines also got ruptured and decreased pressure makes it impossible to control the spread of fire. In earthquake of San Francisco in 1906, more deaths happened because of fire as compared to earthquake itself.
When severe shaking occur then soil or sand loses their strength for a temporary period and gets converted from solid to liquid. This liquefaction causes sinking of buildings, bridges etc.
When epicenter of an earthquake is located near sea, then the travelling of seismic waves below the sea causes generation of tsunami waves, which can travel at a speed of 600-800 kilometres per hour. Sometimes when earthquake triggered landslides fall into sea, it also leads to the creation of Tsunami waves.
Scientists have been upgrading a network of seismometers that registers tiny tremors far below. This allows them to better map active faults buried under as much as 12 miles of sand and mud laid down by the mighty rivers that drain the Himalayas. Seismologists in Bangladesh, as part of a project on earthquakes have drilled some 250 wells near riverbeds to take sediment samples. These, they hope, will reveal the scope and timing of past earthquakes and river-course shifts that may have wiped out large swaths of countryside–though at times when population and infrastructure were far less dense. The goal is to give Bangladeshi scientists and leaders the tools they need to understand, and minimize. Unfortunately, until now it is well-nigh impossible to predict earthquakes and these cannot be prevented from occurring. However different measures can be taken to ensure prompt and best possible rescue effort. Building code and rules must be applicable for all construction work done by both public and private organisations.
Currently, buildings that are in accordance with the National Building Code are able to withstand earthquakes of the magnitude of seven on the Richter scale. The government should implement awareness development programmes. Earthquake shelters should be built. Specially needed are squads of well-trained persons in good number from the civil and military forces, plus volunteers, who can be mobilised and put into service--immediately-- to make good use of their expert training in a post-earthquake situation. After some recently experienced tremors, government will be expected to complete such preparations within the shortest time frame. It must not be addressed with the usual bureaucratic lethargy. This task must be addressed with the great seriousness and urgency it deserves.
Perhaps, the Ministry of Disaster Preparedness can be the coordinating and central point of this mechanism in liaison with the ministry of defence, the armed forces, fire brigade, civil defence and other institutions.
In many homes or apartment, there is still no awareness that power and gas connections must be turned off the moment an earthquake is sensed because fires from the damaged transmission lines of the two sources can very seriously hazard even rescue operations after an earthquake
Bangladesh is internationally recognised for its proactive programmes aimed at addressing the risk of cyclone and flood. The country has achieved much in cyclone preparedness and flood management leading to saved lives, reduced economic loss, and protection of development gains. Consequently, Bangladesh is often cited as an example of disaster risk management internationally. Unfortunately, earthquake disaster preparedness is far from satisfactory. If the country is to avert a human tragedy of epic proportions the time to act is now.
The writer is Senior Assistant Editor of The Business Post
