Geomorphology Analysis of Lava Flow of Mt. Guntur in West Java Using Synthetic Aperture Radar (SAR) with Fully Polarimetry

Abstract

Mt. Guntur is one of active volcanoes in Indonesia, which has a very unique product of lava flows than other volcanoes. In order to minimize the adverse effects of volcanic eruptions of Mt. Guntur, one mitigation measure that can be done is to map the volcano landform through geomorphological analysis and identification of lava flow characteristics. It is very obvious that Mt. Guntur lava flow is visible and clear so it is possible to do the landform lava flow mapping. However, this kind of study is very rare especially in Indonesia. Thus, this research aims to analyse the geomorphologic and identify lava flows using high-resolution optical imagery through characterization (signature) landforms by using L band SAR polarimetry backscattering in combination with decision tree classification techniques using the QUEST algorithm (Quick, Unbiased, Efficient Statistical Trees). Moreover, the accuracy of the classification results is calculated using matrix analysis accuracy and Kappa coefficient calculation. In addition, the characterization of the object is also performed using analysis of spectral separation. The analysis showed that the geomorphological analysis can be used for volcanic (V) landforms mapping based on morfocronologi aspect. The identification of the image depends on the spatial resolution of the image. The objects were identified using IKONOS imagery, Google Earth, and PALSAR imagery. The results of showed that the HV and VV polarization serves as the best combination to identify the lava flows. Classification results showed a good accuracy value which is 51.80% with a Kappa coefficient of 0.43. This suggests that the identification of a lava flow using linear polarization combined with decision tree classification has a good level of confidence.