The massive 8.8 quake that hit Chile last week was amongst one of the most powerful quakes recorded. Not only did it impact the lives of thousands living in Chile but is has permanently changed the very shape of our planet.
A megathrust earthquake is caused when one one tectonic plate is shoved violently underneath another in a process called subduction. These earthquakes are very rare; they tend to be 7.5 magnitude or higher, and there are only about 14 in recorded history (including the 2004 Indonesian quake that caused huge tsunamis).
As the Nazca and South American plates collided, the Nazca plate slid under and all that mass was pulled closer to the center of Earth, affecting it’s spin. The planet is now spinning slightly faster, making our days 1.26 millionth of a second shorter.
How does this work? Think of it just like a spinning skater brings her arms in closer to her body to rotate faster.
Where might the next megathrust quake hit? Scientists believe it could be in a subduction zone off the Pacific coast of the Northern US and Canada, where the Juan de Fuca plate meets the North American plate. Geophysicists have used computer modeling to show what such a quake would look like, based in part on data they’ve reconstructed about a 9 magnitude quake there in 1700. The researchers estimate that megathrust quakes hit the region about every 400-500 years, so we’re about due for another.
via Gizmodo
Categories: Science
Tags: 8.8, chile, earthquake, gizmodo, plates, quake
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