Abstract
Karangsambung, located in Central Java, Indonesia has complex geological conditions of the tectonic evolution of Java Island due to the subduction process of the India-Australia plate with the Eurasian plate in the Cretaceous-Paleocene. The tectonic movements in the subduction zone have resulted in diverse geological structures and rock types and impact the morphological shape of the study area. The level of tectonic activity in the study area can be determined using a tectonic geomorphological approach. A digital elevation model and geographic information systems are used for geomorphic data processing. Geological data observations were also carried out in the form of river terraces. Seven geomorphic index parameters have been calculated to determine the youngest tectonic activity through the relative tectonic activity index (IAT) of the study area: the ratio of the valley floor width to the valley height, the drainage basin asymmetry, the river gradient-length index, the basin shape index, mountain front sinuosity, drainage density, and the hypsometric integral/hypsometric curve. The IAT score is divided into four classes which are class 1 (0%) very highly, class 2 (13%) highly, class 3 (56%) moderately, and class 4 (31%) low. The IAT shows that the research area is categorized as an active tectonic area so that the morphology formed is more influenced by tectonic activity than erosion. Geological data analysis on uplifted and deformed river terrace outcrops shows that the study area is affected by neotectonic activity.
Highlights
Tectonic geomorphology research is very important to obtain information on neotectonic activity over a large area
The approach of this paper has been to use data extracted from geomorphic indices as a quantitative method to provide evidence of variations in tectonic activity
The tectonic geomorphic index is a tool to analyze the influence of active tectonic in a large area using geographic information system (GIS), which is based on the value of the ratio of valley floor width to valley height (Vf), drainage basin asymmetry (AF), stream length – gradient index (SL), the basin shape index (BS), mountain front sinuosity (Smf), drainage density (Dd), and the correlated hypsometric integral/hypsometric curve (HI / HC) obtained active tectonic index (IAT) values, namely high tectonic activity (13%), moderate tectonic activity (56%), and low tectonic activity (31%)
Summary
Tectonic geomorphology research is very important to obtain information on neotectonic activity over a large area. Tectonic geomorphological analysis has been widely used as a parameter to measure earthquake hazard in an area (Galadini and Galli, 2000; Faghih et al, 2015; Keller and Pinter, 1996; El Hamdouni et al, 2008; Yudhicara et al, 2017; Hidayat, 2010). In terms of regional geology, the study area has very complex geological characteristics because it is the result of the subduction process between the India-Australia Plate and the Eurasian Plate in the Cretaceous-Paleocene (Asikin, 1974). The Karangsambung area describes a diverse morphology consisting of sedimentary hills, structural hills, solitary hills, plains (denudational), and the struc-
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
