Devil’s Hole is a deep, shaded, natural pool near Death Valley, in Nevada, that is home to some very specialized species of fish and is thus heavily studied. It’s also just the right size to be excited by low frequency “teleseismic” waves from distant earthquakes.
When large earthquakes happen anywhere on the planet, the seismic waves they emit ripple around the globe, detected in most places far from their epicenters only by extremely sensitive instruments. For instance, when the 7.4 earthquake struck the coast of Mexico a few weeks ago, it excited surface waves that raced dramatically beneath our feet in the U.S. imperceptibly to us. By the time seismic waves reach these great distance they are both weak and extremely low-frequency. Sensitive seismometers, however, easily pick up their signal.