The Morphotectonic Study Based On The Mountain Sinuosity (SMF) Method in Kramat And Surrounding Area, Karangmoncol-Purbalingga District

Abstract

Abstract. The study area is in the Karangmoncol District and its surroundings, Purbalingga Regency, Central Java Province, Indonesia. The study was conducted to determine the level of tectonic activity using morphometric analysis in the slopes and valleys. The analysis carried out is Mountain Front Sinuosity (Smf). Geological mapping was carried out to determine the types of rocks in the research area. Smf measurements were carried out on each rock group. Smf measurement is done by selecting a certain elevation contour line facing the valley. Two points on the contour line are connected by a straight line. The value of Smf is calculated by dividing the length of the selected contour line (Lmf) by the length of the straight line of two points on the contour (Ls). The rock of the Halang Formation in the northern part of the study area which is old (Late Miocene) has a high Smf value (3.89 points) which indicates it is not tectonically active. The rock of the Kumbang Formation in the middle of the study area that is old (Late Miocene) has a moderate Smf value (2.67 points) which indicates it has a weak tectonic level. The rocks of the Kumbang Formation are composed of volcanic rocks such as lava, breccia and tuff that are dipped to the south. The young Tapak Formation rock (Pliocene) in the southern part of the study area has a high Smf (3.16 points) which indicates it is not tectonically active. Keywords: tectonic, morphometric, formation, Miocene, and rock.