Ferris Bueller once wisely taught us that life moves pretty fast, and if we don’t stop and “look around every once in a while,” we might miss it. But sometimes, life actually moves pretty slow, as in the case of geophysics, making it hard to notice the monumental changes that take place over the course of years, decades, or beyond, beneath our day-to-day radar. With the proliferation of satellite imaging, and the advent of Google Earth, we’re beginning to capture these slower-moving Earth changes like never before. And seeing them compressed into a time-lapse GIF, like this one of a river in Peru, is downright enlightening.
Shown above is the Ucayali River, and here you’re watching it evolve over the course of 28 years, from 1985 to 2013. This particular GIF was made by sedimentary geologist Zoltan Sylvester (yes, we want his name too), who selected the Ucayali for a time-lapse presentation of “meander migration” because it happens relatively quickly here.
A meander is—regarding river formations—a bend in a river that starts out subtle, but grows more and more exaggerated over time. In fact, meanders in rivers can become so exaggerated that they develop into crescent-shaped loops on one or another side of the original river, effectively cutting themselves off and becoming “oxbow lakes.” This exaggeration of a meander into a full-blown oxbow (which totally sounds like a difficult gymnastics routine), is displayed perfectly in Sylvester’s GIF—a little below and to the right of the image’s center.
Meanders form thanks to differences in flow speed of the water in a given river. For example, if a hole is dug out on one side of a straight river (by an animal or some other force), water from the river will rush in to fill that hole. This rush of water is moving faster than the water flowing along the other side of the river, and will thusly break away more of the river’s solid surrounding. This causes a cascade effect, which is amplified as the slower-moving water on the opposite side of the river fails to pick up the same sized sand that the faster side can, which forces a buildup of solid material that displaces that portion of the river. As this breaking down of earth on the faster side and a building up of earth on the slower side occurs, a meander is formed. A great explanatory video of this process is provided by MinuteEarth, which can be found here.
Perhaps the best part about these kinds of geophysical time-lapse GIFs is the fact that you can go to Google Earth right now, pinpoint almost any area on Earth, and watch it evolve over time since 1984. Beware however, as you may become mesmerized. Although even Ferris would agree that this is something you won’t want to miss.
What do you think about this time-lapse of the Ucayali? Let us know in the comments section below!
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HT: FlowingData
Images: Hindered Settling
