Changes

==Variable area wiggle trace==

==Variable area wiggle trace==

The variable area wiggle trace is the commonly accepted work horse in the petroleum exploration field. Each trace displays the data associated with its common depth point as a continuous trace oscillating on either side of a zero amplitude line (Figure 1a). Commonly, the area of the curve (trace or “wiggle”) to the right of the zero line (positive or normal amplitude) is shaded black, while the negative side to the left is unfilled (Figure 1b). The shading need not start at zero, but the area to be shaded (either positive or negative) may be selected to enhance the visual display of the amplitudes desired. This shading of part of the area of the curve gives the display its name ''variable area wiggle trace'' (Figure 1c). The term ''bias'' is used to describe the type and amount of shading desired. Zero (0) bias means all positive amplitudes are shaded. A 25% positive bias means the shading is offset by 25% of maximum amplitude from the zero line. A negative bias tends to shade in more of the negative values. Another factor is the choice of the trace deflection or excursion. A 2.5 excursion allows the maximum amplitude of the trace to cross over 2.5 trace spacings. This greatly affects the look of the data.

[[file:displaying-seismic-data_fig1.png|thumb|{{figure number|1}}Various types of seismic displays: (a) wiggle trace, (b) variable area, (c) variable area wiggle trace, and (d) variable density. Copyright: Conoco Inc.]]

[[file:displaying-seismic-data_fig1.png|thumb|{{figure number|1}}Various types of seismic displays: (a) wiggle trace, (b) variable area, (c) variable area wiggle trace, and (d) variable density. Copyright: Conoco Inc.]]

The variable area wiggle trace is the commonly accepted work horse in the petroleum exploration field. Each trace displays the data associated with its common depth point as a continuous trace oscillating on either side of a zero amplitude line ([[:file:displaying-seismic-data_fig1.png|Figure 1a]]). Commonly, the area of the curve (trace or “wiggle”) to the right of the zero line (positive or normal amplitude) is shaded black, while the negative side to the left is unfilled ([[:file:displaying-seismic-data_fig1.png|Figure 1b]]). The shading need not start at zero, but the area to be shaded (either positive or negative) may be selected to enhance the visual display of the amplitudes desired. This shading of part of the area of the curve gives the display its name ''variable area wiggle trace'' ([[:file:displaying-seismic-data_fig1.png|Figure 1c]]). The term ''bias'' is used to describe the type and amount of shading desired. Zero (0) bias means all positive amplitudes are shaded. A 25% positive bias means the shading is offset by 25% of maximum amplitude from the zero line. A negative bias tends to shade in more of the negative values. Another factor is the choice of the trace deflection or excursion. A 2.5 excursion allows the maximum amplitude of the trace to cross over 2.5 trace spacings. This greatly affects the look of the data.

==Variable density and superimposed displays==

==Variable density and superimposed displays==