Friday’s aftershock does not signal major quake risk: Seismologists

Kathmandu, March. 1: Many people, whose sleep was disturbed by the 6.1 magnitude earthquake that jolted Kathmandu and other parts of the country at 2:51 am on Friday, suspect whether the quake was a sign of a bigger quake risk.  

However, seismologists have said that it will not be right to assume that frequent tremors signal the risk of a major earthquake. They said that earthquakes cannot be predicted.

Also, the quake of Friday morning with its epicenter at Bhairabkunda area of Sindhupalchok district was an aftershock of the Gorkha Earthquake of April 25, 2015.  However, it was felt in almost all parts of the country as well as in some areas in India. Seismologist Mukunda Bhattarai said that Friday’s was not a fresh but an aftershock of the 2015 earthquake.

Frequent aftershocks do not imply that there is risk of a major earthquake immediately, he said.  

“The aftershocks of earthquakes occurring in the area indicate that seismic energy is accumulating there. If minor earthquakes continue, there is a possibility of a major earthquake in the future,” he said, “However, as of now, it is not possible to predict when an earthquake will occur.”

"It can be measured and its vibration can be detected just a few seconds before it strikes with the help of an advanced technology. But they also cannot do anything, precautions of a few seconds before a quake hits can only help save life and property," said Bhattarai.

According to seismic data collected so far by the National Earthquake Monitoring and Research Centre under the Department of Mines and Geology, 820 earthquakes above 4 Richter on scale, mostly aftershocks, were recorded from 2015 to February, 2025. 

"But when we start counting seismic records after the Gorkha Quake, more than 55,000 aftershocks measuring below 2 to four and above in Richter scale within these years," said Bhattarai.  

The NEMRC generally keeps seismic records of only above 2 magnitudes. However, quakes of less than 2 magnitude are recorded if they hit the Kathmandu Valley, according to Bhattarai. 

Earthquake disaster management professional and expert on seismology activities Dr. Amod Mani Dixit, said that after a major earthquake, aftershocks could continue for a long time.

“The earthquake of Friday morning is an aftershock of the powerful 7.6-magnitude earthquake of 2015,” Dr. Dixit said. “Such aftershocks can continue in this region for many years.”

He said that occurrence of only a stronger earthquake (more than 7.6 magnitude of Gorkha) in the affected areas (hit by the Gorkha quake region) could be classified as a new and fresh earthquake. But in case of Karnali and Sudurpashchim provinces, new quakes are occurring almost every day or a week of interval, claimed Dr. Dixit. 

“In eastern and central Nepal, any earthquake smaller than the Gorkha earthquake is considered an aftershock,” added Dr. Dixit. 

 Senior Seismologist Dr. Lok Bijaya Adhikari and chief of the National Earthquake Monitoring and Research Centre said, “The Gorkha earthquake of 2015 caused disturbances within the Earth’s crust in this area (eastern and up to central region), which have not yet returned to normalcy. The rocks have not yet been settled, indicating that the effects of the Gorkha earthquake are still ongoing.”

Dr. Adhikari added that it is impossible to predict how long the aftershocks would continue. According to him, aftershocks from a powerful earthquake that struck the United States 200 years ago are still occurring.

“We do not have records of how long aftershocks continued after the 8.3-magnitude earthquake that struck eastern Nepal in 1934. Nepal started maintaining systematic earthquake records only after 1980. Dr. Adhikari noted that more than 55,000 aftershocks have already occurred since the Gorkha earthquake. According to him, the earthquake that struck Sindhupalchok on Friday was moderate in magnitude.

An earthquake of this magnitude can destroy weak structures, he said. “However, many structures in the area have been reconstructed after the Gorkha earthquake. Since the new buildings were constructed following proper standards, and the powerful aftershock of this morning did not cause significant damage in Sindhupalchok.”

He warned that if an earthquake of this magnitude were to hit western Nepal, it could cause substantial damage to structures. 

“Today's earthquake did not cause major destruction because of the strong and well-built structures constructed after the Gorkha earthquake,” he said. This earthquake has sent a message that to prevent earthquake damage, buildings must be strong and constructed according to proper standards, he added. The occurrence of small earthquakes in an area suggests that energy is being stored for a larger earthquake, Adhikari said.