Geeking out with gPhones

By way of brief summary, a gPhone is a gravity meter that sits around for days or weeks or months or years and measures gravity very extremely precisely.  People usually use them for measuring Earth tides really really well, because apparently that's interesting to some people.  Me, I'm primarily interested in figuring out how the gPhone has gone haywire this time.

Oh dear.  I haven't explained Earth tides OR measuring gravity on this blog yet, have I?  Right then, that'll be a future post.

For now, though, you are going to indulge me in my nerdiness by geeking out with me over this lovely seismic signal that showed up in all three of the data sets I was analyzing today:

Isn't it GLORIOUS??  You can even see the P and S arrivals!!!!  This is the 6.9 magnitude earthquake that occurred off the coast of Northern California on the evening of Sunday, March 9, 2014.

It turns out that in addition to being good at measuring Earth tides really really precisely, gPhones also make pretty good long-period seismometers.  What's really cool is that these meters are so sensitive they can detect ocean waves crashing on the shore - and we're in Colorado.  Now, you won't see individual wave crashes, more just a lot of noise in a certain frequency range, but if you set up two gPhones right next to each other and look at the gravity they measure over time, this "noise" will look exactly the same, which means it's a real signal, not just some noise from the machine itself.  This completely blew my mind when someone first told me what that was.

GRAVITY IS AWESOME!!!