KATHMANDU, Feb 18: A new scientific study has refuted estimates that a major earthquake could strike northern India and western Nepal in the near future. The conclusion is based on an analytical study of sediment cores extracted from the depths of Rara Lake.
Some scientific assessments had argued that a large earthquake in the region was already “overdue.” However, the study notes that small to medium-sized earthquakes have been occurring irregularly in the region for thousands of years.
Researchers from the British Antarctic Survey (BAS) analyzed earthquake records preserved up to 6,000 years old in the depths of Rara Lake. The study, launched in 2013, examined geological changes observed beneath the lake.
This is the longest record collected so far in the Himalayan region. According to the researchers’ findings, major earthquakes do not occur at regular intervals but in an irregular manner. Such earthquakes are sometimes highly active and at other times followed by long periods of calm.
During the study, scientists argued that this high-altitude lake in Nepal serves as a natural archive of seismic history.
According to scientists, when strong shaking occurs, underwater slopes are disturbed, forming distinct layers at the bottom of the lake. In a press release issued last Wednesday while making the study public, BAS said the research team identified around 50 such layers over a 6,000-year period.
Over 15,000 visited Rara Lake in a year
The new study, published in the scientific journal Science Advances, overturns prevailing assumptions about earthquake prediction. “The belief that large earthquakes occur in fixed cycles and that a particular region may be overdue for the next major quake is not scientifically correct,” the study states.
The study concludes that earthquakes mainly occur irregularly and that far more earthquakes have already occurred in the region than previously assumed.
Scientists have found evidence of at least 50 earthquakes of magnitude 6.5 or higher in the region over the past 6,000 years. Of these, eight have occurred since 1505. These earthquakes did not occur at regular intervals but in an irregular pattern.
According to the study’s lead author, BAS seismologist Dr Zakaria Ghazoui Saus, the claim that a major earthquake is “overdue” is merely a myth. Large earthquakes, like smaller ones, are irregular and unpredictable, he said. “The science is clear—large earthquakes do not follow a timetable,” he said.
Because there has been limited evidence of earthquakes in western Nepal, the region was believed to have a “seismic gap,” raising fears that a large-scale earthquake could strike soon. However, lead researcher Dr Ghazoui Saus said this was not a “seismic gap” but rather a “knowledge gap.”
Under this study, researchers for the first time statistically tested the Himalayan geological record alongside modern, instrumentally recorded earthquake data. They then compared the results with long-term earthquake records from Indonesia, New Zealand, Chile, and the Pacific Northwest region of the United States.
According to the researchers, the same pattern was observed everywhere: earthquakes cluster irregularly, with active phases followed by long quiet periods. They noted that no region showed a regular or cyclic pattern of earthquakes, aligning with the study’s conclusion rather than assumptions made by other risk assessment models.
Scientists say the study challenges older models. Seismic risk assessments often use “periodic” or “quasi-periodic” recurrence models to estimate the likelihood of large earthquakes. Based on limited observations, these computer models assume earthquakes occur in near-regular cycles. However, the new research shows this assumption to be unfounded.
According to the British research body, this study represents the first statistical comparison in Nepal and the wider Himalayan region between geological records and modern instrumental data, linking deep geological time with contemporary seismology.
“The long-running debate over earthquake periodicity in the Himalayas should be brought to an end, and there should be agreement that this is an irregular process. Risk assessments must be framed within that reality,” lead researcher Dr Ghazoui Saus said. “Six thousand years of data show that small and large earthquakes can occur at any time. This significantly increases estimated seismic risk and has direct implications for government policy, public investment, and disaster preparedness priorities.”
Scientists believe the findings send an important message for earthquake preparedness across the Himalayan region stretching from Afghanistan to India, Nepal, China, and Myanmar. “We recommend that the public, politicians, and policymakers treat seismic risk as an ever-present but uneven threat,” Ghazoui Saus said. “Large or small earthquakes can occur during both active and quiet periods.”
A decade ago, in 2072 BS (2015), a devastating earthquake in Nepal killed nearly 9,000 people. The study, however, serves as a reminder that seismic risk has not diminished. Uneven enforcement of building codes, rapid urbanization, and limited public budgets continue to heighten vulnerability.
Researchers have emphasized the need for a comprehensive governance approach. They recommend strict enforcement of building codes in new construction, rapid retrofitting of critical infrastructure such as schools and hospitals, and the development of investment and response plans that account for both clustered seismic activity and prolonged quiet periods.
The Himalayan range was formed by the collision of the Indian and Eurasian tectonic plates—a process that is still ongoing. As a result, the region remains one of the world’s most seismically active zones. The study was conducted under a project called “The Big Thaw,” funded by the Natural Environment Research Council.
The project aims to improve forecasts of snowfall and other hazards in high-altitude regions and to expand collaboration with researchers in Nepal and around the world.
