Tremors Hit Earthquake-Prone Zone Parts of India after Assam Earthquake

A call for a better disaster plan was brought out after a 6.4 magnitude earthquake was felt in the grounds of Assam, a state of India.

On a Wednesday morning of April 28, the residents in Dhekiajuli, a district of Assam, were awakened by a tremor which caused panic and extensive damage to the state.

The National Centre for Seismology (NCS) last recorded in its bulletin that the earthquake's epicenter (lat: 26.69, long: 92.36) has a depth of 17km and lasted for approximately 30 seconds. The shake was felt around 7:51 a.m. and originated 43km west of Tezpur, Assam, India.

A few hours later, aftershocks with magnitudes of 4.7-3.6 were recorded.

The tremors' effect to Northeast of India

Fortunately, there were no severe damages to any infrastructure or serious injuries recorded due to aftershocks in Assam. However, tremors were felt across the Northeast parts of India, reporting several damages to buildings and structures, and the unfortunate death of a 70-year-old man named Prasanna Kalita due to cardiac arrest when aftershocks hit.

Down to Earth reported in its interview with a 32-year-old resident of Dhekiajuli named Sanjit Mandal, that he saw several cracks on his old concrete house which eventually 'crumbled due to the jolts'.

Another resident said that the earthquake was the most severe among the ones he had witnessed in his life.

Within 100km from the epicenter, several damages of buildings and infrastructures were also recorded in the areas of Sonitpur, Nagaon, Guwahati and Udalguri.

These incidents call for disaster mitigation policy makers to bridge the gaps and formulate a more meaningful earthquake damage mitigation plan.

According to scientists Nilutpal Bora and Prakash Barman, highly fragile and earthquake-prone zone areas like some parts in Northeast of India require integrative disaster plan to address high-intensity earthquakes, such as the recent one that rocked Assam.

Furthermore, NCS reported the recent tremor has been attributed to the Kopili fault zone.

Attributes of the Kopili fault

A study of the Kopili fault zone was said to have a maximum potential of strong ground motion in Northeast India. In the recent event, NCS stated that the Kopili fault was close to Himalayan Frontal Thrust, associated with collisional tectonics due to the Indian Plate subducting beneath the Eurasian Plate.

The fault itself, which has a 300 km long and 50 km wide lineament, is a transpression type, which deviates from simple shear and undergoes strike-slip deformation.

It is currently confirmed to be the most active seismic zone in Northeast India.

Bora, a former Raman-Charpak Fellow in the Department of Civil Engineering, explained that alluvial soils characterized in the Kopili fault zone and its neighboring areas have a high tendency of trapping seismic waves, making the Northeast India more prone to earthquakes.

As Northeast India becomes highly prone to earthquake occurrences, what happened to Assam struck awareness to not just them, but people in India, especially the authorities to create and strengthen an integrative mitigation plan to prepare for natural disasters such as large earthquakes.