Geometric Attributes of Polygonal Crack Patterns in Columnar Joints
AbstractA well-ordered polygonal crack pattern is frequently observed on the
outcrop surface of columnar joints. The crack pattern's geometry and
topology result from the volume contraction of solidified lava during
thermal dissipation. In this study, we conducted field measurements of
columnar joints at four different sites with various lithologies in
Japan to understand the influence of geography and lithological
character on their geometric characteristics. Drone-aided photography
and computer-based image analysis enabled us to examine the constituent
polygons' geometric attributes and their statistics with high accuracy.
This methodology revealed a relationship between the geometry and
topology of the polygonal crack patterns. Moreover, we established a
positive correlation between the polygon area and the number of vertices
of a polygon at each study site, irrespective of lithology, or
geographic position. These results are consistent with previous
investigational studies, in particular starch-based analog experiments.