Comments
The earthquake of magnitude 8.6 that struck the coast of the Indonesian island of Sumatra on Wednesday afternoon was completely different from the killer 9.1 magnitude one of December 26, 2004.
While the 2004 earthquake triggered devastating tsunami waves, causing havoc across several countries including India, the present one luckily did not, because of this difference in fault mechanism, say earthquake experts from the National Geophysical Research Institute (NGRI) here,
Today's earthquake occurred due to a ‘strike slip fault'. In this mechanism, two plates slide past each other in the earth's crust. This resulted in the sea waters not being pushed with force in an upward direction.
Hence, the earthquake did not trigger major tsunami activity.
In the case of the 2004 earthquake, the high magnitude of 9.1 coincided with a vertical thrust movement of the two plates, forcing the water being displaced with force upwards, hence tsunami waves were generated, explained Mr R.K. Chadha, seismologist of NGRI.
Aftershocks
The reason why the INCOIS, the Indian Tsunami warning centre also gave a ‘watch' alert for tsunami was because of the observed mechanism of the present earthquake, he told Business Line .
The NGRI, a premier lab studying earthquakes in India, recorded the huge earthquake. It has also recorded 12 aftershocks so far.
The epicentre of the present earthquake is around 150-200 km of the earlier one, in the Sumatra-Java subduction zone. The region is highly active seismologically, with recordings of 4-5 tremors of magnitude 4 on a daily basis, he added.
The impact of such earthquakes can be felt along the coast up to 2500 km.
Hence, people feeling the shocks in Chennai, coastal Andhra Pradesh and Kolkata have been reported, Mr Chadha said.
Comments
COMMENT NOW
Comments
Comments have to be in English, and in full sentences. They cannot be abusive or personal. Please abide by our community guidelines for posting your comments.
We have migrated to a new commenting platform. If you are already a registered user of TheHindu Businessline and logged in, you may continue to engage with our articles. If you do not have an account please register and login to post comments. Users can access their older comments by logging into their accounts on Vuukle.