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A new study published in the journal Science Advances shows that massive earthquakes are just as random as small ones. A team of researchers led by Zakaria Ghazoui-Schaus at the British Antarctic Survey reached this conclusion after analyzing sediments from Lake Rara in Western Nepal.
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Then they compared the time intervals between these events using mathematical models to see if they followed a pattern. They found no evidence of a regular schedule. The gaps between them were irregular, driven by chance rather than a predictable clock, as they note in their paper.
"Our results imply that the occurrence of major earthquakes is as uncertain (Poissonian) as the one of moderate to small earthquakes, irrespective of the time scale considered, thereby considerably increasing seismic hazard and exposing Himalayan countries to a permanent threat of large to major earthquakes."
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Therefore, according to the team's findings, we cannot necessarily assume a period of safety after a big quake. Because the threat is permanent and unpredictable, earthquake-prone regions and countries should update their preparedness so they are always ready for the next big one.