Seismic Anisotropy In The Edwards Formation: Government Canyon State Natural Area

High resolution seismic data are acquired from the Edwards limestone formation in an area of<br>outcrop within the Government Canyon State Natural Area, to infer the local orientation of vertical<br>fracturing. The experiment consists of a single 3D seismic array of 16 3C recording stations. Seismic<br>sources are deployed around and within the array at short spacings resulting in 16 3C source gathers<br>(by reciprocity) with thousands of traces. A velocity-variation-with-azimuth trend is discernible in<br>the data attributable to azimuthal anisotropy due to vertical fracturing. A slow direction along<br>120 degrees from North is found, with a fast direction along 20 degrees from North. If vertical<br>fracturing and seismic anisotropy are correlated at this site, a fracture orientation along 20 degrees<br>from North is determined.