A new study has debunked the popular theory that a massive earthquake in the Himalayas is 'overdue', finding that large earthquakes do not follow predictable cycles. Researchers analysed 6,000 years of earthquake records from sediments in Rara Lake, western Nepal, and concluded that major quakes are as random and unpredictable as smaller ones.
The study, published in the journal Science Advances, examined layers in lakebed sediments disturbed by strong shaking. Scientists identified about 50 such layers spanning 6,000 years, and compared them with modern instrumental data and records from Indonesia, New Zealand, Chile, and the US Pacific Northwest. Everywhere, earthquake patterns were found to be irregular, with active periods followed by quiet spells.
Lead author Dr Zakaria Ghazoui-Schaus from the British Antarctic Survey said: 'Our research shows that major earthquakes are just as random and unpredictable as smaller ones. The science is blunt: major quakes don’t run to a timetable.' He added that 6,000 years of data show major earthquakes can happen at any time.
The findings have significant implications for earthquake preparedness across the Himalayan zone, from Afghanistan through India, Nepal, China, and Myanmar. Despite Nepal's devastating 2015 earthquake, which killed about 9,000 people, the research suggests seismic risk has not diminished. The authors urge regional authorities to enforce building codes and retrofit existing high-importance buildings like schools and hospitals.
'We recommend that the public, politicians and policymakers should treat earthquake hazards as a constant, uneven threat,' Dr Ghazoui-Schaus said. 'Response plans need to be ready for bursts as well as lulls in earthquakes of all sizes – because the next event, big or small, could happen at any time.'
