252 Geophysics in Geothermal Exploration Figure 8.10 AVAZ (left) and VVAZ (right) anisotropy at 700 ms time slice. The same visual can be performed highlighting the areas with no signal (low energy) and conventional fracture attributes (3D similarity), Figure 8.11. The low energy areas, in pink, indicate no information rather than no anisotropy. The conventional fracture attributes, in black, indicate the presence of faults and fractures at greater scale, completing the understanding of the anisotropy distribution. In these maps, some blocks between major faults can be affected or not by anisotropy, which may indicate the presence or absence of fractures. Figure 8.11 AVAZ (left) and VVAZ (right) anisotropy at 700 ms time slice, with weak signal areas in pink. From Top Cretaceous to Top Dogger, The AVAZ results highlight similar areas (Figure 8.12), while VVAZ results vary at these same levels (Figure 8.13), indicating a poor compatibility between AVAZ and VVAZ. The strong amplitudes of the Top Cretaceous may affect the deeper events, showing therefore similar anomaly areas. The VVAZ does not depend on this amplitude effect and may be more reliable from below the Top Cretaceous down to the Top Dogger.
RkJQdWJsaXNoZXIy NjA3NzQ=