If vertical scale is exaggerated by 2x in a geological cross-section, what happens to the apparent dip?

• A. The apparent dip becomes steeper
• B. The apparent dip remains unchanged
• C. The apparent dip becomes shallower
• D. The dip orientation reverses

Answer: (A)

When vertical scale is doubled in a geological cross-section, the bed’s rise for every horizontal unit is shown as twice as large, so slopes look steeper. If the true dip is θ, the apparent dip φ on the section satisfies tan φ = k * tan θ, where k is the vertical exaggeration factor. With a 2x exaggeration, tan φ = 2 tan θ, so φ = arctan(2 tan θ). Since arctan increases with its input, φ is greater than θ for any nonzero dip, meaning the apparent dip becomes steeper.

For example, a true dip of 30° (tan ≈ 0.577) gives φ ≈ arctan(1.155) ≈ 49°, clearly steeper. A true dip of 60° (tan ≈ 1.732) gives φ ≈ arctan(3.464) ≈ 74°, even steeper. The orientation of the dip stays the same; only the angle changes due to the vertical stretch.