MAPPING FOR GRAVEL POTENCY OF VOLCANIC HUMMOCKBASED ON AERIAL PHOTOGRAPHY MAPPINGIN JEMBER REGENCY, JAWA TIMUR

• Main Author: Moonstar Adi Nugroho, Ray
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/76848
• Institution: Institut Teknologi Bandung

Hummocks are morphology resembling small hills formed by the deceleration of volcanic avalanche material. This study aims to apply the aerial-photograph mapping of hummocks morphology in the distal zone of the Mt. Raung volcanic avalanche in the Jember area, East Java. The data obtained is processed to perform digital elevation models (DEM) which are then used to estimate the volume of identified hummocks. In addition, X-Ray Diffraction (XRD) analysis, petrography, and grain-size distribution analysis were also carried out from several samples of volcanic hummocks material. The expected output of this study is volume data of volcanic hummocks from the results of aerial-photograph mapping which could represent the potential volcanic products as construction materials in this area, as well as to confirm the compatibility between XRD and petrographic data for the process of ancient volcanic avalanches that have occurred. The data used in this study were 16 aerial-photographs data from drones, 10 rock samples, and 14 soil samples that make up the volcanic hummocks. Based on the results of mapping, 21 volcanic hummocks with a total volume of around 760 thousand m3 can be identified. The results of the analysis of XRD and petrography show that the rock material that makes up the hummocks are made from magma which has basaltic acidity and most likely came from intrusion under the hummocks. The rock mass is dominated by minerals of plagioclase groups. Olivine, which mostly can only be found in basaltic rocks, is also present. The result of grain-size distribution analysis shows that mean grain size shrink the further it moved from its original point. Grain size distribution also shows a bimodal distribution which characterize avalanche-debris materials that has been transported through long distances.