Watch the waves from the M6.4 southern California earthquake roll across the USArray seismic network (http://www.usarray.org)! This animation, called a Ground Motion Visualization (GMV), shows the motion of the ground as detected on USArray seismometers - each dot is a seismic station and when the ground moves up it turns red and when it moves down it turns blue. Earthquake waves travel around and through the earth, but they get smaller (attenuate) as they move away from the earthquake location,