Tuesday, December 12, 2017

Moving and Shifting

November 30, 2017 by · Leave a Comment 

 

Courtesy NOAA

When you’re on the boat, you’re always moving, even when you seem not to be going anyplace. Although you’re tied to a dock or attached by an anchor or mooring, the wind and current moves you. Perhaps there’s wave activity as well. But that’s not all, as far beneath you there’s movement of the earth’s crust shifting the entire covering of the planet.

The crust of the earth is not one solid surface like the outside of an egg. It’s instead composed of plates that are miles thick. There are major and minor plates underneath the land (continental plates) and below the ocean (oceanic plates). They move based on the heating and cooling activity deeper into the earth — picture the lid of a pot on the stove rattling around as the boiling water turns into rising steam. That change of plate positions across the planet is known as tectonic shifts.

Courtesy US Geological Society

The plates usually shift at a very slow pace (think about giant tortoises plodding along in slo-mo or nails growing). In many areas, the change may be less than an inch per year, but in some places such as California, the plates may move up to two inches per year. Should the plates meet up or slide past each other, an earthquake is likely to happen. If they shift away and create a gap (scientists call it a rift) then magma (what rises from a volcano) reaches the surface and new land is formed. A sea can also develop — a rift created the Red Sea.

There’s a lot more to learn about what’s going on beneath us while we’re bobbing on a boat or sitting at the kitchen table. Geologists, oceanographers, and seismologists are three of the types of scientists who study this topic, looking at the past, the present, and the future of earth’s movable crust.

Want to learn more about what’s going on below the ocean’s waters and ground? Check out these resources:

https://earthquake.usgs.gov/learn/animations/divergent.php

https://coast.noaa.gov/psc/sea/content/plate-tectonics-0

http://easyscienceforkids.com/all-about-tectonic-plates/

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