Changes

==Example of seeing faults==

==Example of seeing faults==

[[file:interpreting-3-d-seismic-data_fig13-2.png|300px|thumb|{{figure number|1}}From Dorn.<ref name=Dorn_1998>Dorn, G. A., 1988, [http://library.seg.org/doi/abs/10.1190/1.1438121 Modern 3-D seismic interpretation]: The Leading Edge, v. 17, no. 9, p. 1262-1271.</ref> Courtesy SEG.]]

[[file:interpreting-3-d-seismic-data_fig13-2.png|300px|thumb|{{figure number|1}}Images from a 3-D survey in the Gulf of Mexico. From Dorn.<ref name=Dorn_1998>Dorn, G. A., 1988, [http://library.seg.org/doi/abs/10.1190/1.1438121 Modern 3-D seismic interpretation]: The Leading Edge, v. 17, no. 9, p. 1262-1271.</ref> Courtesy SEG.]]

[[:file:interpreting-3-d-seismic-data_fig13-2.png|Figure 1]] shows several images from a 3-D survey in the Gulf of Mexico. Figure 2a is a dip magnitude map at an interpreted horizon in the data, showing several steep dip (pink) lineaments associated with normal faults that cut the horizon. Arrows ''b'', ''c'', and ''d'' show the orientation and direction of three traverses cut through the volume at angles of approximately 90°, 45°, and 10° to the trace of the fault in the center of the horizon. Figures 2b, c, and d are traverses ''b, c'', and ''d'', respectively. The fault is clearly interpretable in the centers of the traverses that cut the fault at angles of 90° and 45°. However, it would be very difficult to interpret the fault on Figure 2d, the oblique traverse. This geometric effect produces a blind zone on vertical sections that are oriented between +/–20° of the trend of a fault. As a result, if you are only interpreting vertical seismic sections, you will fail to see faults that have trends in this zone. The same phenomenon occurs with depositional stratigraphy.

[[:file:interpreting-3-d-seismic-data_fig13-2.png|Figure 1]] shows several images from a 3-D survey in the Gulf of Mexico. Figure 2a is a dip magnitude map at an interpreted horizon in the data, showing several steep dip (pink) lineaments associated with normal faults that cut the horizon. Arrows ''b'', ''c'', and ''d'' show the orientation and direction of three traverses cut through the volume at angles of approximately 90°, 45°, and 10° to the trace of the fault in the center of the horizon. Figures 2b, c, and d are traverses ''b, c'', and ''d'', respectively. The fault is clearly interpretable in the centers of the traverses that cut the fault at angles of 90° and 45°. However, it would be very difficult to interpret the fault on Figure 2d, the oblique traverse. This geometric effect produces a blind zone on vertical sections that are oriented between +/–20° of the trend of a fault. As a result, if you are only interpreting vertical seismic sections, you will fail to see faults that have trends in this zone. The same phenomenon occurs with depositional stratigraphy.