Quake biggest in NE after 1988

By Our Staff Reporter

Guwahati, Jan 4: Monday's earthquake measuring 6.7 on the Richter scale was the biggest felt in Assam since 1988.

On August 6, 1988, a magnitude 6.8 earthquake shook the region at around 6.30 am in the morning.

That epicenter of that quake was about 50 km from today's, and both were on the Indo-Myanmar subduction zone. Both the quakes occurred as the result of strike slip faulting in the complex plate boundary region between India and the Eurasia plate.

But the 1988 quake had occurred at a depth of 91 km, and today's quake occurred at a depth of 55 km.

 "A lot of stress had accumulated since the release of energy in 1988. The stress accumulated over a period of time was released today," said a senior seismologist.

Moderate quakes are welcomed by seismologists as it helps release the energy intermittently, instead of keeping it captive and accumulating the stress.

Eighteen to twenty earthquakes of above 4.5 magnitude are felt in the NE region, most of them epicentered on the Indo-Myanmar border, every year.

The Northeastern region, lying in the highest seismic risk zone, has experienced some of the worst quakes in the world, be it the Shillong quake of 1897 or the Assam quake of 1950, both measuring around 8.5 and reckoned to be two major quakes in human history, both in terms of intensity and destruction.

The 1897 quake that occurred in the Shillong plateau left 1,542 people dead, while the one on August 15, 1950 killed over 750 people.

On October 11, 2000, a quake was felt in the region which had an intensity of 6 in the Richter Scale.

On September 21, 2009, an earthquake measuring 6.2 on the Richter Scale was felt in the region. The quake left over half a dozen dead in neighboring Bhutan where it was epicentered.