Characterization of volcanic geomorphology and geology by slope and topographic openness

We used a digital elevation model (DEM) of Iwate Volcano, Japan to calculate slope and topographic openness for every geological unit in that area. Further, we conducted principal component analysis (PCA) and stepwise discriminant analysis (SDA) to evaluate statistical differences in the morphometric parameters of the geological units. We categorized the geological units according to their ages and their formation processes. The categorization based on formation processes was as follows: lava-flow/lava, central cone/stratocone, air fall deposit, pyroclastic flow deposit, volcanic fan deposit, and debris avalanche deposit. PCA allowed us to select geological units suitable for analysis, while SDA was used to select some morphometric parameters, which could explain the differences in the formation processes and ages of the geological units. We found that the formation processes correspond well to mean slope, and that the geological ages that control the degree of surface dissection correspond well to the standard deviations of slope and negative topographic openness.