THE ACTIVE FAULT DETECTION BASE ON MORPHOTECTONIC CHARACTERISTIC OF CIKERUH WATERSHED, WEST JAVA']JAVA, INDONESIA

The purpose of this study was to identify active faults using watershed morphometric and morphotectonic data, both subjectively and statistically. The data were obtained through the extraction of topographic maps and satellite imagery at the geomorphology and remote sensing laboratory. Field observations were carried out to supplement the existing data, namely fractures and morphotectonic units. Most of the data comes from literature studies. The probabilistic approach is used in the data analysis to obtain significant results. The results showed that the study area is included in the active fault zone. This is proven by the results of the variable analysis of the watershed morphometric and morphotectonic, i.e., bifurcation ratio (Rb), drainage density (Dd), and mount-front sinuosity (Smf). Rb1-2 values ranged from 1.17 to 2 and Rb2-3 ranged from 1.5 to 3. This value indicates that the active faults control the Cikeruh watershed, especially the upstream. The Dd ranged from 3.4 to 7.5, indicating that the landscape texture is classified as moderate to very smooth. The fault activities categorized as weak to medium, represented by Smf values, ranged from 1.18 to 2.83. Geological structures formed in the area of research are fractures and faults. The phenomenon of active faults is also supported by data from field surveys, including the valley and ridge lineaments, escarpment, and anomaly curve of the river.