Air-noise reduction on geophone data using microphone records

This paper proposes using microphone recordings of air waves, recorded close to a geophone, to suppress air-wave noise on the geophone. The types of air-wave noise on the geophone may include air-coupled ground roll, air blast, ground-coupled air blast, and wind noise. Microphone recordings of air waves are related to ground measurements and geophone disturbances. We can thus attempt to use the air wave to filter the geophone data. Tests on recordings from the Calgary General Hospital implosion on October 4, 1998 indicate success in reducing noise on the geophone data. I propose designing a geophone with an attached microphone to reduce noise on the geophone data. INTRODUCTION Air blasts, ground-coupled air waves, and air-coupled ground are all potential problems in recording seismic signals. These noises can certainly overwhelm subsurface reflection signals, especially when the noise source is near the receivers. While there are many ways to filter this noise, it still can be a problem, due to aliasing, for example. In addition, winds above a certain speed can create unacceptably high noise levels and shut down seismic acquisition operations. Some ambient noise can be attenuated, in the marine case, by recording pressure (hydrophone) data along with geophone measurements. The hydrophone information is used to suppress fluid-reverberations in the geophone data. Similarly, we might consider suppressing air-associated noise, recorded on a geophone, by use of output from a nearby microphone.