Wouldn’t it be great if earthquakes happened slowly instead of just snapping and shaking us all up?
Well, sometimes they do in subduction zones. It’s called “slow-slip” or episodic tremor seismicity.
Geologists have been studying this mysterious seismographic signal for almost two decades now. And this week a team of researchers reportedly discovered what might be going on.
Pictures are worth thousands of words, so let’s check out two videos.
The first is from New Zealand, where the subduction zone setup is fairly straightforward:
Exactly the same thing is currently going underneath me, here in the Pacific Northwest. Thanks to modern technology and cool seismologists, I can watch it happen in almost real time!
This slow-slip energy release can only be picked up by instruments, but when the next big “snap” comes, I may see my house here (located 70-some miles from the sea, on the inland side of the Coastal Range) drop about 30 feet and move roughly 100 feet in the general direction of the sunset, along with the rest of the Willamette Valley.
Why? This geologic setting is more complicated.
That’s a little technical, so feel free to imagine my house moving instead of those orange arrows if you feel yourself start to go numb.
Featured image: Seattle’s Space Needle at Christmas, Andrew E. Larsen, CC BY-ND 2.0