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:

http://youtu.be/dx4OqT0PYnU&rel=0

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?

http://youtu.be/HL3KGK5eqaw&rel=0

Of course, the bottom line is what controls the shaking you’re going to feel at any given location.

http://youtu.be/BP7gKXLjqxk&rel=0

Here is more information about the USGS Shakemap. Outside the US, check with your local, regional, and/or national geoscience institutions for more information.

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Featured image: Damage from a 1976 Guatemala earthquake, by USGS, via Wikimedia.