Tectonic Control of the Nanggulan Formation Based on Morphometric Analysis in Kulon Progo, Indonesia

DOI:10.17014/ijog.9.2.147-157 Outcrop of Nanggulan Formation, surrounded by Old Andesite Formation (OAF) in the eastern part Kulon Progo Dome, is very limited. Tectonic control interpreted as a contributing factor. activity can be shown morphometric aspect. The research purpose was to calculate valley floor - height ratio, stream gradient index, and drainage density Formations. method used field survey Shuttle Radar Topography Mission analysis. focused on Clumprit, Klepu, Kalisonggo Rivers. total number segments for 223 with length 4.62 km, while OAF 101 3.55 km. SRTM analysis showed that segment 55, 1.48 ratio measured ten valleys eight valleys. In value from 1.00 5.46 (low uplift), whilst OAF, results vary: 1.35 4.58 0.59 (medium 0.43 (high uplift). index 460.47 tectonic), 723.84 tectonic). 10.35 km/km 2 (very smooth landscape texture) (somewhat texture). Morphometry proves tectonic more active, causing exposed surface.