Comparison of Air Photo Lineations and Joint Patterns, Dartmoor, Southwest England
Abstract
Joint spacing and orientation data were collected at 58 sample sites in the field. Lineations delineated on 1:24,000 and 1:50,000 scale air photo mosaics were digitized, and orientations of and spacings between lineations were determined using a Geographic Information System (CAPIR). Common trends for lineations on both photo mosaics and from outcrop are east-northeast (40-90) and west-northwest (300340). Thus, lineations from the air photos and the fractures in outcrop probably comprise samples from the same population, but different individuals are seen at each scale: as scale decreases, visible lineations become increasingly longer and more widely spaced. Although the joint and lineation spacing distributions are significantly different from each other, the three distributions have similar modes (100 + 25). Weaker modes are similarly located near even 100's for all three distributions, suggesting spacing may be periodic. Spacing between fractures increases for similar orientations with decreasing scale. The scale independence of these fractures suggests they are fractal in nature.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 01, 1992
- Accession Number
- ADA252017
Entities
People
- Judy Ehlen
Organizations
- Army Geospatial Center