A Comparison of Trenched Distributed Acoustic Sensing (DAS) to Trenched and Surface 3C Geophones - Daly, Manitoba, Canada

In the fall of 2012 we conducted a field test of a trenched fibre optic Distributed Acoustic Sensing (DAS) system to trenched and surface 3C geophones in the Daly area of southwestern Manitoba, Canada. The test was designed to provide a comparison of the acoustic wavefield as measured by the trenched fibre, the trenched 3C geophones and surface 3C geophones. The geophone data is of exceptional quality as is normal for this area. The fibre (DAS) data show clear reflection, refraction and coherent noise signal but at a lower signal-to-noise ratio than the geophone data. It was also noted that for our acquisition geometry, it was difficult to separate the different modes based on particle motion and so we had to rely on PP and PS velocities for this. Furthermore, we were not able to separate the radial and transverse PS modes on the fibre data.