Asked in EarthquakesFossil FuelsPlate Tectonics
What is the highest reading on the Richter scale of an earthquake?
March 13, 2011 1:01PM
The Richter scale has no upper and lower values, although in practical terms the lowest magnitude earthquakes that are capable of being recorded have a Richter magnitude of -3 (the minus numbers occur because Charles Richter chose an arbitrary seismic wave amplitude to equal a magnitude of 1 and seismometers have become more sensitive since then, so smaller seismic waves can be detected leading to magnitude values lower than 1).
Conversely, the largest-ever earthquake recorded was a magnitude 9.5 event which occurred on May 22, 1960, in Valdivia, Chile.
Some more background information
It is thought that the asteroid impact event that occurred at the Cretaceous-Paleogene boundary, 65.5 million years ago and thought to have contributed to the extinction of the dinosaurs (creating the Chicxulub crater), would have emitted energy equal to an earthquake of magnitude 12.5 on the Richter scale.