Scientists have found evidence that an earthquake 3,800 years ago in Northern Chile is the largest in human history, according to a new study. The quake had a magnitude of around 9.5...
The largest known earthquake before the new study was the 9.5 magnitude Valdivia earthquake, which struck Southern Chile in May 1960....
And they know the older 9.5 is bigger than the newer 9.5 because the older 9.5 had a 1000 km crack, while the newer 9.5 had a 621 mile crack.