Landform classification for the Philippine Sea based on DEM data

Submarine geomorphology plays significant roles in marine environmental and engineering studies, and the deep sea is specially complex in geomorphology. Based on the existing norms, standards and regional tectonic evolution characteristics, this paper takes the Philippine sea as the research object for study of deep sea geoenvironment. Quantitative standards are proposed and six different geomorphic units are identified, which include seamounts, hills, submarine rifts, mountain valleys, intermontane depressions, and intermontane basins. Based on DEM, ArcGIS is used to extract critical geomorphological factors such as elevation, slope, slope change and relief of land surface. Following the classification, the study area is quantitatively divided into six geomorphic units. Controlled by the tectonic stresses in different periods, the west part and the east part of the survey area show significant difference in tectonic strikes. The oceanic ridges in the west are arranged in a near-EW pattern, and the hills in the east are in a near-NS direction. Ridges are narrower in the west. Large-scale geomorphic units, such as seamounts and intermontane basins are often controlled by strong geological processes, such as magmatic, hydrothermal and tectonic activities. Facts have proved that this research is helpful to submarine landform classification and the study of their genesis. It can also contribute more to the formulation of relevant standards and specifications for deep sea geomorphological studies.