Bangladesh, located close to the plate margins of Indian and Eurasian plates, is susceptible to earthquakes. The collision of the Indian plate moving northward with the Eurasian plate is the cause of frequent earthquakes in the region comprising Bangladesh, India, Nepal and Myanmar.
Historically, Bangladesh has been affected by five earthquakes of magnitude (M) greater than 7 (Richter scale) between 1869 and 1930. Among them, the mighty 8+ magnitude 1897 Great Indian earthquake in Shillong, Assam had an epicentral distance of about 230-km from Dhaka. The 1885 Bengal earthquake (M=7, 170 km from Dhaka) and 1918 Srimongal earthquake (M=7.6, 150 km from Dhaka) had their epicenters within Bangladesh and caused considerable damage. Two great (M>8) earthquakes occurred in Bihar in 1934 and in Assam in 1950, but they were too far to cause any damage in Bangladesh.
It should be noted that large earthquakes in the region have not been occurring for quite a long time (around 75 years), hence, the possibility of a major earthquake occurring soon is quite high. According to Prof. Bruce Bolt of University of California at Berkeley, large magnitude earthquakes generated in four tectonic zones can affect Bangladesh.
We are, indeed, living with the possibility of a major earthquake hitting Bangladesh. We need to think about the extent of damage likely to be caused by such an earthquake. The urban areas in Bangladesh have developed at a fast pace, resulting in extensive construction of multi-storied buildings.
In the absence of legal enforcement of the building code and lack of awareness, many multistoried buildings have been constructed without proper precautionary measures against earthquake. The various factors contributing to the earthquake risk in the urban and rural areas of Bangladesh may be summarised as: (i) absence of large earthquake for many years; (ii) awareness; (iii) high population density and construction lwithout earthquake resistant design; (iv) absence of legal enforcement of building code and its seismic design provisions; (v) poor quality of construction materials and improper construction method; (vi) economic limitations; (vii) possibility of fire outbreaks due to rupture of gas pipelines or electric short-circuit during an earthquake, and inadequate fire fighting facilities; (viii) inadequate road width and space between buildings, preventing rescue operations and fire-fighting vehicles from reaching certain areas; (ix) inadequate exits for the occupants of a building during an emergency; (x) lack of facilities (rescue equipment, trained staff, medical personnel, and medical facilities) and preparedness for emergency response and recovery operations following an earthquake; (xi) lack of earthquake-resistant design of power plants, power stations, bridges, communication control stations, gas and water supply stations.
Environmental and socioeconomic risks:
(i) Loss of natural ecosystem; (ii) loss of natural biodiversity; (iii) loss of many human lives; (iv) loss of many domestic animals; (v) washing away of fishery farms; (vi) damage to infrastructures; (vii) damage to cold storages; (viii) thousands of people rendered homeless; (ix) damage to crops and croplands; (x) damage to many industries; (xi) damage to many commercial facilities; (xii) damage to many service centers (medical, gas and water supply, etc.); (xiii) damage to many educational institutions; (xiv) outbreak of diarrhoeal and infectious diseases; and (xv) famine in the affected areas.
Preparation of buildings:
(i) Identification and repairing of cracks developed on the roofs and walls of all buildings; (ii) examination of all buildings regarding earthquake sustainability, and reinforcing them in order to achieve required strength and flexibility.
Precautionary measures in construction of new buildings:
(i) Compliance with the governmental and technical rules for constructing new buildings; (ii) observance of building codes; (iii) construction of strong bases in accordance with the height and weight (load) of buildings; (iv) use of reinforced concrete in all buildings; (v) installation of gas and electric lines safely; (vi) careful construction of buildings on soft or muddy soil.
Preparation for earthquake:
Everybody must be aware of and be ready for an earthquake, and (i) identify the risky locations and the safe places in rooms; (ii) identify the safe way for getting out during earthquake; (iii) keep heavy things in lower floors; (iv) keep file cabinets and heavy furniture fixed with hooks; (v) arrange regular earthquake rehearsal in educational institutions, hospitals, residences, etc.
What to do during earthquake:
(i) Take shelter under a table, bed or bench; (ii) stay away from glass windows, heavy objects, chemicals and hanging objects; (iii) don't jump from the building; (iv) stay away from buildings, giant trees, power and gas lines while outdoors; (v) try to take shelter in open space; (vi) shutdown the power line or switch.
What to do after earthquake:
(i) Come out as rehearsed. Mind that the door is the weakest point of a building; (ii) take shelter in open and designated places; (iii) don't enter broken down buildings and the extinguish fire, if any; (iv) do rescue work; (v) give first aid to the injured people and if required rush them to hospital; (vi) listen to the emergency instructions on radio and television and follow them; (vii) don't use telephone and cell phone because it may hamper the communications of the Emergency Service Department; (viii) cooperate with the government and non-government organisation in maintaining rules and discipline and in giving proper information.
The writer is an Environmentalist.
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