Frequent earthquakes in Northeast India; should we be worried?
Just a week ago on Saturday at 11.08 pm, an earthquake measuring 5.3 on the Richter scale jolted Northeast India including Assam, Manipur, Tripura, and Mizoram. This is the third earthquake that rocked Assam and the second one in Manipur only in the last two months alone.
It is a well-known fact that the region of Northeast India is highly vulnerable to earthquakes as geomorphologically this region falls under Zone V in the seismic map of India. The Northeastern Region has experienced 18 large earthquakes (M>7) during the last hundred years.
This including the great earthquakes of Shillong (1897) and the Assam-Tibet border (1950) both with M=8.7. This is leaving several small and microearthquakes which has also been recorded frequently in the region. The high seismicity in this region can also be attributed to the collision tectonics between the Indian Plate and the Eurasian Plate in the north and subduction tectonics along with the Indo-Myanmar range (IMR) in the east.
Historically speaking, earthquakes during the non-instrumental period occurred during the years of 1548, 1596, 1601, 1642, 1663, 1696, 1756, 1772, 1838, and 1841. Earthquakes during the instrumental period can be listed during the years of 1869, 1897, 1923, 1930, 1943, 1947, 1950, 1985, 1984, and 1988. This can also be a sign of the fact that frequent and major earthquakes, in the long term basis prediction, is likely to occur in this region.
The high vulnerability and seismic risk in India can be attributed to the fact that 10.9% of its geographical area falls in the seismic Zone V. This zone is vulnerable to very high seismic risk. Add on to it that 17.3% of India’s geographical area falls in seismic Zone IV which is also vulnerable to high seismic risk. Clubbed together, these two zones alone covers 28.2 % of India’s geographical area.
229 districts of India fall within seismic zones IV and V according to the Vulnerability Atlas of India prepared by the Building Materials Technology Promotion Council (BMTPC).
Now, these values are a wholesome view of the entire earthquake scene of India, particularly Northeast India. So to know a bit about the reason behind the recent successive tremors team EastMojo was able to interact with a seismologist who is a government official and under conditions of anonymity stated, “What northeast India has been experiencing these past few months is nothing new. We are anyway in a dynamically active zone and so the change in the frequency of earthquakes should not be surprising.”
He went on to state that we cannot stop earthquakes as it is a natural phenomenon. All one can do according to him is to sensitize ourselves to the dangers of living in an earthquake-prone area which includes the need to construct earthquake-resistant structures.
“Many believe that these small tremors are a sign of a major earthquake to come but it is not a scientifically backed fact and so there is no need to panic,” he said adding, “it’s the panic that causes death and not the earthquake.”
He concluded by saying that in scientific terms what we are facing is a normal phenomenon for Northeast faces tremors of a minimum 5 magnitude every 100 days.