Massive EarthQuake Hits NE,India

The earthquake measuring 6.8 on the Richter Scale,  which hit the east and north east (NE) region, was the biggest in 20 years, officials said.

Records of Central Seismological Observatory here showed increasing seismic activity in the region.

The epicentre of the earthquake lay in the Sikkim-Nepal border region. But it was felt widely, all the way from New Delhi to Mizoram.

However, there were some reports of minor damage in concrete houses in the region.

The Geological Survey of India had earlier notified that mountainous northeastern region could experience a devastating earthquake as the region, according to seismologists, falls in zone V, the sixth worst quake-prone belt in the world.

Initial analyses suggest the earthquake was complex, likely a result of two events occurring close together in time at depths of approximately 20 km beneath the Earth’s surface. At the latitude of the September 18 earthquake, the India plate converges with Eurasia at a rate of approximately 46 mm/yr towards the north-northeast. The broad convergence between these two plates has resulted in the uplift of the Himalayas, the world’s tallest mountain range. The preliminary focal mechanism of the earthquake

suggests strike slip faulting, and thus an intraplate source within the upper Eurasian plate or the underlying India plate, rather than occurring on the thrust interface plate boundary between the two.
This region has experienced relatively moderate seismicity in the past, with 18 earthquakes of M 5 or greater over the past 35 years within 100 km of the epicenter of the September 18 event. The largest of these was a M 6.1 earthquake in November of 1980, 75 km to the southeast.