Earthquakes can happen anywhere, but are much more likely to happen where tectonic plates are rubbing against their neighbors. Seismic Explorer is an interactive map that displays every earthquake of magnitude 5 or above that has occurred since 1980. You can use the slider to show their collective progress over time, or play it like a video. Zoom in or out to identify the activity in your area. Clicking on an earthquake dot will bring up more information about it.
Change the parameters to show where the boundaries of the tectonic plates are, although they are hard to see during the most recent dates because they are covered with earthquakes. That's okay, because you can change the map to get the tectonic plates labeled, or indicate their direction of movement.
You can also add in volcanic activity, which follows the same boundaries more or less. It's very clear where the Pacific Ring of Fire is, and that line of quakes in the middle of the Atlantic show where the continents are pulling apart. There's a key in the upper right to help you make sense of the colors and sizes of the visual data (the blue earthquakes are the deepest). Pulling the timeline slide back and forth is pretty trippy, and it shows how the earth is a clearly amazing and dynamic planet. -via Kottke
btw: loving your map blog, such a goldmine of wonderful maps held within, thanks for sharing.