Registration of infrasound pulses from open-pit explosions
Acoustic (infrasound) signal generated by open-pit explosions can be so strong to be registered by seismic sensors (see figure).
It is easy to check that a signal is infrasonic one by a seismic group. Apparent velocity of such waves computed by time shifts between channels corresponds to sound velocity 0.33 km/sec.
Array data processing software MTR even has a built-in subsystem for acoustic signals determination.
After installation of infrasonic system our sensibility for acoustic signals increased significantly. Using microbarographs we register acoustic signals from all mines of our region.
It is clear that existence of acoustic signal after seismic event is a reliable criterion that the event is of technological origin.