On contemporary Earth, the bulk of truly big earthquakes are a result of plate tectonics and are set off by huge crustal plates bumping against, sliding past, or undercutting one another. It’s long been debated just how early in Earth’s 4.54 billion-year-old history such tectonic activity began, with some asserting it was no earlier than 2.8 billion years ago. But two geologists believe they’ve found telltale evidence of a big “megathrust” earthquake that occurred perhaps as far back as 3.6 billion years ago.
Writing in the journal Geology, Cornel de Ronde (GNS Science, New Zealand) and Simon Lamb (Victoria University of Wellington, New Zealand) assert that a folded block of chert in South Africa holds evidence of underwater landslides so massive they must have been driven by a massive earthquake.
Not everyone is convinced. But if ultimately proven correct, this would prove to be the first recorded earthquake in Earth’s history and would push tectonic activity back by nearly a billion years.