Electromagnetic emission accompanying fracture of quartz‐bearing rocks

Fracture of quartz‐bearing rocks and other hard piezoelectric materials is associated with radio frequency (RF) electromagnetic emission that can be readily detected in the laboratory. Using a standard RF coil and a transient recorder it was found that small cracks in quartz and tourmaline single crystals produce exponentially‐decaying RF transients with a time constant of about 10 −5 s. Failure of quartz‐bearing rocks generates longer and more...