Have you ever wondered how seismologists locate earthquakes and figure out their magnitude?
Here is a video about it from New Zealand’s GNS Science:
They changed over from the Richter scale to moment magnitude because there are other factors involved, including physical qualities of the rock that breaks in a quake and – spaghetti?
Of course, the bottom line is what controls the shaking you’re going to feel at any given location.
Here is more information about the USGS Shakemap. Outside the US, check with your local, regional, and/or national geoscience institutions for more information.
Featured image: Damage from a 1976 Guatemala earthquake, by USGS, via Wikimedia.