Earthquake Detector Could Have Helped During Quakepocalypse

[Andrea] built a seismic wave detector that warns of a possible impending earthquake. Because P waves travel much faster than the “make everything shake” S waves, building a device that detects P waves serves as an early warning system that alerts building occupants to go under a door frame. [Andrea]’s build detects these fast-moving P waves and only took an hour to make.

Last August, those of us on the east coast of the US had to live through Quakepocalypse, a magnitude 5.9 earthquake centered around Middle of Nowhere, Virginia. For those of us who have decided to stay, rebuild, and put our garden chairs upright again (so brave…), [Andrea]’s build could have been very useful.

The mechanics of the build is very simple: a pair of springs and levers are electrically wired together so that whenever there’s a sudden shock, a buzzer goes off. It’s very similar to an ancient Chinese earthquake detector that detects P waves by dropping a ball into a frog’s mouth.

While we’re not sure if a few of [Andrea]’s devices would be needed to detect P waves coming in off-axis, the build is simple enough to build dozens of them. Check out the video of the build in action after the break here.


13 thoughts on “Earthquake Detector Could Have Helped During Quakepocalypse

  1. Also, while P waves travel at nearly twice the speed of shear waves, how much time does that really buy you for big shaking considering that energy also follows an inverse-square relationship so the further away you are, the more likely you don’t need to run and hide (although the type of ground you’re sitting on will also have a strong impact on the shaking).

  2. 5.9? Ha! Last year I had the joy of a 7.1 10km away. Did I pick the wrong night to leave the water in the sink… The P-wave woke me, just longer enough to say “What the F@#k?” and the S-waves trashed everything.

    In any sizeable aftershock you feel the P-wave before the S-wave, but as they are all local you only get a seconds notice – just long enough to turn to each other and say “Earthquake????”, and then play “guess the magnitude”.

    Even that gets tiresome after a while. Check the link if you want to see a mashup of the 7,640 quakes we have had in the last year.

    Unless there is a really, really, really big shake (8 plus) to give you enough warning to do anything useful (e.g. to pull your trousers up if are were using the toilet), and thankfully really big shakes are really rare!

  3. And every single “p wave detector” I have seen fails to work around any freeways, highways, city streets, or railways.

    Far too much heavy equipment make “p waves” and trucks slapping a highway seam makes p waves.

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