The USArray project has produced a remarkable animation showing how earthquake waves travel across massive expanses of landmasses. As you'll see in this video, these waves are a lot like ripples on a pond. Very powerful ripples.
To create this visualization, the USArray deployed a mobile network of seismometers across the U.S. — and they've been doing so for over a decade. Incredibly, the devices are so sensitive that they can measure ground movements less than the width of a human hair.
This work is similar to the one being done by seismologists at Berkeley and Caltech who recently created a visualization of earthquakes coursing through California.
The above animation, which comes via LiveScience, pieces together six earthquakes that occurred between 2007 and 2013 — the most recent of which was on October 19, 2013. Each quake was centered in the Gulf of California between mainland Mexico and the Baja peninsula, and each was about a magnitude 6.0.
Stephanie Pappas explains:
By gluing together the recordings from the seismometers during each quake, researchers can see what it would have looked like to have the whole country covered by seismometers during a quake like this.
The animation first shows a faint signal from the conglomerate quake's P-wave, or the compressional wave that starts to make the ground shake. Next, a strong ripple travels from the Baja region northeastward as the seismometers pick up the surface waves, where energy moves close to the Earth's surface. The surface shaking is stronger in the Southeast, where the soil is loose and moves like Jell-O, than in the rest of the country, where hard rock is closer to the surface. (This soil difference is why a 2011 earthquake in Virginia was felt throughout the East Coast.)
Fascinatingly, the animation shows the physics of the quake, sending energy out in all directions, with the signature of that energy revealing how the fault actually moved. Normal measurement techniques almost never show this.
Read the rest of Pappas's post at LiveScience.