One of the most exciting parts of participating in a large online course about cartography is the sheer coolness that gets shared by others in the forum.
Lindsey H., of Linden, VA, and, independently, Francis Baum, of University City, MO, recently shared maps they’d made in the Cartography MOOC where they had color-keyed earthquakes by their depth (as well as scaled them by magnitude), an independent extension of one of the course exercises. It was a wonderful visual representation of the direction of subduction along tectonic plates showing clearly which plate was diving beneath the other. So simple and revealing. Nice work, Lindsey and Francis!
I was curious if the trend would be so clear for other plates so I took a look at the data and found these interesting boundaries. Purple quakes are near the surface while the yellow quakes are up to 700KM deep.
Fiji
Indonesia
Japan
South America
I’ve played with earthquake data for a while now and never noticed that wonderful signature of tectonic movement and quake depth. I’m indebted to Lindsey and Francis, and a host of the wonderful MOOC participants, for their energy and insights in the process of the online course. I learned a great deal from them. That’s probably one of the more common bonuses that you’d hear from educators. I was happy to get a chance at pretending at it for a while.
Adventures In Mapping 
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