"Vibrations" seen on many of the stations monitoring of seismic activity in the official centers and capture the CERI / Midwest USGS throughout the region. This can only be described as the ultimate low vibration, a very large area.
They should not be confused with earthquakes in other places around the globe, is that previously observed for such a large area.
Maybe in the sensor network there are any failures? Maybe something is causing these "noise"? Or that the fixed monitoring stations are detected low-frequency vibrations that occur in reality?
Could this be a sign that will soon begin in Yellowstone eruption? Or maybe wakes up the New Madrid?
Time will tell what it is …