A LEADING daily on Tuesday said that during an earthquake in Dhaka city, gas, electricity, water, and sewerage lines would be damaged incalculably and the number of casualties would be so high due to fires that rescuers would most likely be incapable of tackling the situation. To apprehend the likely catastrophe caused by earthquake, Dhaka South City Corporation (DSCC) has decided to set up five earthquake sensors at the edges of Dhaka city so that utility service providers could get 10 to 15 seconds due to the early warning system. This step of DSCC is timely and highly praiseworthy since few days ago our neighbouring country faced an earthquake of 7.5 magnitude.
Earthquake warning sensors’ few seconds of admonition before a major earthquake could save lives. An earthquake mainly generates two kinds of seismic waves which are P and S waves. P waves travel faster than S waves and rarely causes any damage. This sensor can provide warning to people before the S-wave arrives with the strong shaking that usually causes most of the damage. If the system is set in the fault zone of Dhaka city, earthquakes can be detected earlier and people living far away from the fault zone can be warned so that they can evacuate buildings and move to safer places.
These warning sensors in Dhaka city would be more appropriate in avoiding possible damage to utility networks. Expert said that 35 percent area of Dhaka city corporations and 60 percent area of Rajuk are vulnerable to the risks of utility network-related hazards in the event of an earthquake. So, the mayors requested the utility service providers like Dhaka WASA, Dhaka Power Distribution Company Ltd, and Titas Gas Transmission and Distribution Company Ltd, to take necessary steps to install the sensors so that the connections of gas, electricity and water could be shut down automatically in the event of an earthquake. The quality of soil is to be improved to reduce the possible damage to utility networks and buildings. So, soil can be improved by injecting cement water mixture under very high pressure through the method of ‘jet grouting’. Research reveals that warning sensors will give warnings in the case of quakes of at least 5.5 magnitude. But for the vulnerable buildings of Old Dhaka, this technological device would be of no use as it would be damaged by seismic waves lower than that generated by a 5.5 magnitude quake .
Now, it is necessary to demolish all vulnerable buildings and other unfit infrastructures of Dhaka city. As Earthquake Early Warning (EEW) system is an extremely expensive system, a group of scientists believe that smartphones could do the same work and at a much more affordable cost. Most of the mobile users in Bangladesh are smartphones users. So, EEW system could be expanded all over the country that may play crucial role to save the lives of the people from the calamity of earthquakes.
