There were very insignificant damages to buildings here in Bangladesh in the last two days’ earthquakes. But should that give us any relief to think that even a 7.8 magnitude tremor would not affect us much? Not at all, earthquake experts say.
Bangladesh was saved this time because the epicentre was about 700 to 750 kilometres away in Nepal.
“So even if the magnitude of the earthquake was 7.8 on the Richter scale, its intensity in Bangladesh was very low, about 4 to 5 on the intensity scale – Modified Mercalli Intensity Scale,” said Dr Mehedi Ahmed Ansary of civil engineering department of Bangladesh University of Engineering and Technology. “This is why we saw little damage. In Nepal where the epicentre was, the intensity was 9-10. Damage depends on the intensity scale.”
However, Ansary warns the Nepal earthquake may trigger major tremors in Bangladesh as the earth plates are interconnected.
Magnitude of the quake as described popularly on Richter scale shows how much energy is released at the epicentre. To understand this one can say the Hiroshima atom bomb had released energy equivalent to a 5 magnitude earthquake.
Every point increase in the scale means 32 times more energy released. So a 6 Richter scale tremor is 32 times deadlier than a 5 Richter scale quake in energy eruption.
On the other hand, intensity is determined from effects on people, human structures, and the natural environment as defined by the United States Geological Survey.
And what if Bangladesh faces a 7-8 intensity earthquake? And how can that happen?
Source: The Daily Star