Quake jolts Barak valley, focus on active fault lines

Special Correspondent

SILCHAR, April 25: Entire Barak Valley along with rest of north east was hit by jolts around 11:45 am today, creating panic among in-house residents and people on the streets on move or in vehicles bound for different directions. People were seen rushing out of their homes and shops and those travelling by vehicular mode of transport looked surprised by the suddenness of the unusual happening. According to reports, the earthquake was measured on 7.9 Richter scale with its epicentre at Pokhara in Nepal. The quake was 31 kilometres deep. Being the epicentre, Nepal was badly rocked, leading to heavy casualties and loss of properties.

The tremor has again brought to the fore the relevant question about the vulnerability of this southern most part of Assam. The tremor, however, according to prelimiry report from other parts of the valley caused no damage or loss of life. In the wake of the Cachar tremor on March 31 in 1984 which hit Soi block, killing 8 persons in the area, a team of experts from Regiol Research Laboratory, Jorhat, and ONGC geologists from zira and Dehradun carried out investigations to find out the causes of earthquake, pinpoint its epicentre and all other structural causes.

 Their observation is that earthquakes generally occur in regions of marked instability of the earth’s crust, such as geologically young mountains. Such a region is the zone of the Himalayas. It is therefore not surprising that Barak Valley along with entire Assam is an extended part of the Himalayas and therefore frequently shaken by earthquakes.

 The Himalayas are still going on expanding and this ‘continental drift’ accounts for the drifting of the entire landmass of the north east region from 4 to 5 cm every year. This makes the region, the finding said, seismically active. Moreover, the seismically active belts, Trans Atlantic and Circum Pacific, unite at the corner of Indo–Myanmar, making it most unstable region in the world, according to the experts.

 Though earthquakes are unpredictable in general, it is interesting to note that during the tremor of 1984, the villagers of Soi in Cachar had in particular noticed unusual behavior among bats, birds and squirrels before their area was hit by the quake. Geologists of ONGC in course of their investigations in the area discovered that the earth developed many linear cracks, squeezing out deep grey coloured sand with some clay and hot water.

Their studies have also revealed that a seismic belt termed as ‘Haflong Thrust’ runs through the Borail and North Cachar Hills. As Barak Valley is part of the Arakan basin, tectonic movement results in folding or faulting of the zone which makes it quite susceptible to earthquake.

 Dr. Somth Dasgupta, Vice–Chancellor of Assam University and an eminent geologist with his research work on earthquake, describes Barak Valley as being located in the fifth seismic zone of the country and is highly risky. Though the tremor was measured at 7.9 on Richter scale, the impact was felt severely. He also identified another seismic belt as ‘Sylhet–Fault’ which has caused tremor in the recent past.

 According to records, between 1869 and 2015, Barak Valley has been hit by tremors 18 times, the severest being of 1984, taking human toll. Between 2009 and 2013 alone, the number of quakes counted for 7. All this is an indication of the fact that this valley is highly active seismically and quite turally prone to jolts and tremors. Quite surprisingly, the much hyped disaster magement team was found in slumber without even making its shrill presence.