How Earthquakes Are Measured

Let's say you feel an earthquake of moderate size. Once the shaking stops, you think, "Wow, was that the big one far off or a small one close by? How big was it?" The answer isn't simply one number. Magnitude is certainly one way to describe an earthquake, but what is magnitude? What goes into that measurement? It's also far from the only thing that scientists measure when a quake hits. And while we're asking, how were quakes measured in the past?

Using a scenario Bay Area earthquake as a starting point, seismologist Julian Lozos will describe what measurements happen during, immediately after, and a little while after a big quake. There are also ongoing measurements that help make sense of past earthquakes and possible future ones.

Speaker: Julian Lozos, USGS