This faint tremor, too subtle for humans to feel, has baffled scientists for decades. Earth pulses rhythmically every 26 seconds, detected by seismometers. The phenomenon, known as a microseism ...

Somewhere deep beneath our feet, the Earth appears to be pulsing quietly and rhythmically, every 26 seconds. This faint tremor, too subtle for humans to feel, has baffled scientists for decades.

In March 2010 two borehole strainmeters and three Michelson tiltmeters within the Campi Flegrei volcanic system, Italy, registered an abrupt deformation signal that was followed 20min later by seismic ...