Dip plane

One result which was analyzed in a hydro-fracturing test is shown in Fig. 8.10. Eight AE events are analyzed and plotted in the elevation view. AE events are plotted at their locations from the location analysis. Then, cracks are classified based on the shear ratio. Tensile crack are indicated by arrow s3Tnbols, of which directions are determined from the direction el. Shear cracks are represented by cross symbols, of which two directions correspond to the two vectors 1 and n. Only the event No. 14 was classified into the mixed-mode cracking, and both orientations of the tensile and the shear are indicated. Results are so successful that AE events are located along the dip plane presumed from the dip angle. Remarkably, the directions of crack opening of the tensile cracks are vertical to, and the orientations of the shear cracks seem parallel to the dip plane. 

Fig. 13. Illustration of the concept of dip guided edge enhancement, (a) Derivatives indicating change along the reflector produces a projection with large magnitude in the dip plane, whereas (b) derivatives indicating change orthogonal to the reflector projects with a small magnitude.

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