Analisis Coherence Change Detection Menggunakan Citra Satelit Sentinel 1B untuk Penentuan Cepat Kerusakan Pasca Gempa Bumi Mamuju 14 Januari 2021

Abstrak

The 14 January 2021 Mamuju earthquake caused significant damage to buildings and infrastructure in West Sulawesi, Indonesia. Rapid identification of affected areas is essential to support post-disaster response and recovery efforts. Synthetic Aperture Radar (SAR) remote sensing provides an effective approach for rapid damage assessment because it is independent of weather conditions and daylight availability. This study aims to evaluate the capability of Coherence Change Detection (CCD) derived from Sentinel-1B imagery for rapid identification of earthquake-damaged areas following the 2021 Mamuju earthquake.CCD analysis was conducted using two Sentinel-1B image pairs representing pre-seismic conditions (27 December 2020–08 January 2021) and co-seismic conditions (08 January 2021–20 January 2021). Coherence changes were quantified using the Normalized Difference Coherence (NDC) approach to identify areas affected by surface disturbances. The CCD results were validated using field damage observation data and evaluated through a confusion matrix analysis. The results show that areas affected by the earthquake generally experienced a decrease in coherence values, indicating significant changes in radar backscatter characteristics after the event. Validation results yielded an Overall Accuracy of 62.8%, Precision of 66.7%, Recall of 86.2%, and F1-Score of 75.2%. The high Recall value indicates that CCD successfully identified most of the damaged locations observed in the field. These findings demonstrate that CCD derived from Sentinel-1 imagery has considerable potential as a rapid damage assessment tool for post-earthquake disaster management.