How many aftershocks can there be in one day?
Earthquakes, large and very small, are happening all over the world, all the time. For an illustration of this, click here to see earthquakes that have been located in California and Nevada in the past 7 days. We don’t know exactly how small an earthquake has to be before it can’t trigger any aftershocks, but it is well below the magnitude someone could feel (roughly magnitude 2). Aftershocks and all other earthquakes follow an empirical rule called Gutenberg-Richter Law describing the number of earthquakes of different sizes. This law is a logarithmic relationship* that basically tells us that each time we go down a unit in magnitude, we should expect to see ten times as many earthquakes. So for each earthquake we see of magnitude 5, we should expect to see, very roughly, ten 4’s, 100 3’s, 1000 2’s, etc. The Gutenberg-Richter relationship may break down for the tiniest of earthquakes * (so small that they have negative magnitude), but even so, the number of teeny-tiny aftershocks gene
