Quantitative assessment of relative tectonic activity in the eastern Bandung Basin, Indonesia

Abstract

The Eastern Bandung Basin is composed of predominantly Quaternary volcanic rocks and is influenced by tectonic activity. This research aims to determine and evaluate the morphotectonic characteristics and its implication to the potential geological disaster in the Eastern Bandung Basin. The morphotectonic indices used in this research consist of Stream Length Gradient Index (SL), Asymmetric Factor (Af), Hypsometric Integral (Hi), Ratio of the Valley Floor to the Height of the Valley (Vf), Basin Shape (Bs), and Sinousity of the Mountain Front (Smf). The research area consists of subwatersheds, namely Upper Citarik, Cijalupang, Ciwirama, Ciburial, Cikeruh, and Cimande. The research area is mostly located on hilly to mountainous area with flat to very steep slopes (0–56°). The research area is composed of Quaternary volcanic rocks in the north, east, and south as well as Quaternary alluvium in the central part of the research area. Based on the quantitative assessment, the research area has IRTA values of classes 3 and 4, indicating low to moderately active tectonics. It can be related to active faults and Quaternary volcanic rocks. Class 3 of IRTA corresponding to moderately active tectonics occurs mainly in the Upper Citarik and Cimande subwatershed. Class 4 of IRTA mainly takes place in the Cijalupang. Ciwirama, Ciburial, and Cikeruh subwatershed.

Keywords

• Eastern Bandung Basin
• index of relative tectonic activity
• Morphotectonic
• Sumedang
• quantitative geomorphology