Analysis of Cave Morphology in Wediombo and its Surrounding Area, Gunungkidul

Abstract

Wediombo and its surrounding area is an isolated highland at the southern rim of the Gunung Sewu sub-zone. This area has contact between old volcanic rock with limestone that cave system has underground-hydrological condition. This study aims to determine the morphological characteristics of cave at Wediombo and its surrounding area. This data was collected by observation and cave mapping using the BCRA 5C grade. Data analysis was carried out by passage morphometric analysis and morphographic analysis. This study shows that cave pattern distribution is clustered following the joint and fault lines. The passage morphometry analysis show that Duren and Greweng caves are horizontal with straight passage, while the Pulejajar cave is considered to be a horizontal cave with meander passages. Based on the value of the width and height ratio, the shape of passages are semi-circular with canyon that direction to northeast and southeast. Results of the passage morphography analysis show that Duren and Greweng caves are single and straight passage caves, while the Pulejajar cave is leveled passage and curvilinear branchwork pattern. The cross section variation of the cave passage’s shape are rectangular passage, elliptical passage, canyon, joint passage, gorge sharped passage, keyhole, and chamber.