The IRIS consortium posted this animation of the wave train from today's 5.9 Virginia earthquake as it rolls across the U.S., recorded by seismographs. The big batch of instruments in the center of the country is the current deployment of stations in the USArray network, a 10-year long NSF EarthScope project to image the crust. The stations started on the West Coast and are rolling across the country, staying in one location about two years before moving eastward.
[After repeated tries, I cannot get the video to show the US base map until midway through the animation. Check out the original at IRIS]