A new look at Old Faithful

The Plumbing of Old Faithful

This article looks at current work on the geology of the Old Faitful geyser in Yellowstone National Park.

Old Faithful in action

To look at the subsurface they used portable seismometers and the seismic source used was not hitting the ground with a hammer but the hydrothermal features themselves. 

It turns out that Old Faithful's reservoir is much larger than was thought and extends some distance from the geyser and under several buildings in the area including the iconic Old Faithful Inn!