Low altitude stereo-paired aerial photographs are often used in which investigations?

• A. Mapping soil types
• B. Site histories
• C. Landslide and fault analyses
• D. Urban zoning

Answer: (C)

The ability to see terrain in three dimensions from stereo, low-altitude aerial photographs makes this method especially powerful for identifying and mapping surface expressions of geologic structures and mass-wasting features. With stereo pairs, you can perceive vertical differences and subtle topographic changes that reveal faults, fault scarps, and displaced bedding, allowing you to delineate their extent across an area. The same 3D perspective helps you outline landslides—recognizing their crown, scarp, terraces, and toe—so you can map how far a landslide has moved and how it’s evolved. This combination of depth perception and surface expression is exactly what makes low-altitude stereo photographs particularly well suited to landslide and fault analyses.

Other options are less aligned with what stereo imagery best provides. Mapping soil types relies more on ground truthing, soil profiles, and other data beyond surface height cues, while site histories depend on archival information and stratigraphic records. Urban zoning is about land use and planning rather than interpreting surficial geologic hazards or structures from 3D imagery.