Arup Barua & Shidratul Muntaha :
Earthquake is considered one of the most destructive and terrifying natural forces. The notion ‘Earthquake’ itself generates fear into human minds. Generally it occurs due to sudden transient motion of the ground which leads to release of elastic energy in a matter of few seconds. The cataclysmal impact of earthquake relies upon several points; namely- magnitude of the earthquake, nature of the area, population dynamics, urban landscape etc.
The most traumatic impact of this event/incident is that it may affect a large area, at the same time occurs in a sudden and quite unpredictable way. It can havoc a myriad scale loss of human lives, property, and damage of utility services like supply of water, gas, electricity, transport, communication and many more. History also ratifies that an earthquake could demolish a human civilisation in the worst record.
An earthquake is a series of underground shock waves and movements on the earth’s surface caused by natural processes within the earth’s crust. The idea on interior structure of the earth is quite useful in comprehending this natural occurrence.
Based on the analyses of seismograms of large number of prior earthquakes scientists have discovered that there are three major shells within the earth; they are crust, mantle and core. Crust is the outermost surface of the earth; it is relatively light and brittle. Mantle is just below the crust and extending all the way to the earth’s core. It is a dense and hot layer of semi-solid rock some 2900 km thick. The core is beneath the mantle. It comprises of a fluid outer core and a solid inner core.
The surface of the earth consists of seven major tectonic plates (North American Plate, South America Plate, Antarctic Plate, African Plate, Australian Plate, Eurasian Plate and Pacific Plate) along with number of smaller ones. These plates are moving at different speeds and in different directions from those of the neighbouring ones. The three types of inter-plate interactions are named convergent, divergent and transform boundaries.
Hazards associated with the earthquakes are divided into two forms; primary and secondary earthquake hazards. Primary hazards include fault displacement and ground shaking; secondary hazards entail landslides and avalanches, ground failure, liquefaction, Tsunami etc.
Earthquake can be assessed by using two distinct scales of measurement demonstrating magnitude and intensity. Earthquake magnitude or amount of energy released is determined by use of a seismograph, and instrument that continuously records ground vibrations. A scale developed by a seismologist named Charles Richter mathematically adjusts the readings for the distance of the instrument from the epicenter. A quake of magnitude 3.5 is the smallest normally felt by humans. Richter magnitude over 6 can be destructive any time; magnitude above 8.0 is labeled as great earthquake. Hitherto the largest earthquakes that have been recorded under this system are 9.25 (Alaska, 1969) and 9.5 (Chile, 1960).
Bangladesh has experienced eight major strong ground motion (magnitude over 7.0) in the last two hundred and fifty years, epicenter of that two earthquakes (Srimongal Earthquake of 1918, and Bengal Earthquake of 1885) were located within the country. In addition, three boundary fault lines covering Madhurpur fault, Dauki fault, and Eastern Plate are located within the country.
Considering the geographic location, fault line, population dynamics, urban landscape Bangladesh lies in a hazardous position. Major earthquakes (magnitude ranges 7.0-7.9) may cause demolition particularly in cities. Now questions arise; are we prepared enough to deal with the aftermath of earthquakes? The answer is simply NO.
Several key factors contribute much to vulnerability of human populations in Bangladesh. The key factors are location of settlements in seismic areas, building structures, lack of access to information about earthquake risks. Community preparedness could be a flagship component in mitigating the aftereffects of earthquake. Here local and central government both can intervene to promote community based programs like social map, hazard map, risk and vulnerability map.
The quality of public education in Bangladesh is still not much coeval for mass awareness. Primary and secondary level text books do not reflect the measures to deal with the disaster. Again these sorts of lessons always need hands on exercise from time to time. These days, multimedia classrooms might be instrumental in instructing young students something verdant. Besides, regular mock drill among community would actuate people to act wisely in the right time.
Access to ICT would foster safety and early preparedness during and post disaster regardless rich and poor people. To minimize the loss of human lives, property the proactive initiatives like mapping the vulnerable areas and mass awareness on these issues are quite requisite. Widespread usage of cell phone, internet would be a great source of information to inform people.
It took a long period to develop National Disaster Management Policy-2008, which was initiated after the devastative super cyclone of 1991. Following the draft Standing Orders on Disaster (SOD) was issued in 1997 and approved in 2010. Till then it was the only government approved policy document to deal with these concerned issues. In September 2012, the Parliament had approved the Disaster Management Act following a long endeavor by different quarters including civil society organizations, media, development partners, as well government. Bangladesh National Building Code (BNBC- 2010) still remains in the policy document; its implementation is going through critical remarks.
The capacity of government agencies is not well advanced to rescue a great deal. The recent incidents of Rana Plaza (2013) and Tazrin Fashion (2012) have ratified the scrimpy capacity of national disaster management, but the philanthropic intellect of common people have proved again that these useful hands could be transformed into skilled personnel by functional training and routine follow-up.
