Rapid Mapping of Morphological Change Following the 2024 Ruang Volcano Eruption Using Multi-sensor Remote Sensing Imagery

Ruang Volcano in North Sulawesi, Indonesia, experienced two significant eruptions in April 2024, producing widespread pyroclastic flows and sulfur dioxide emissions that affected areas over 90 km away. Ruang volcano has a history of deathly eruption in 1871 when a tsunami was triggered and caused the deaths of over 400 people. Such history underlines the need to monitor the recent Ruang volcanic activities and associated risks closely. This study demonstrates the integration of high-resolution PlanetScope optical imagery and Sentinel-1A SAR data for near real-time assessment of morphological changes during the 2024 eruption. We show that this multi-sensor approach provides complementary insights: Visual inspection on PlanetScope data captures fine-scale surface features, while interferometric and backscatter analysis on the cloud-penetrating Sentinel-1A data reveals deformation information. Our analysis reveals substantial shoreline expansion (20–70 meters) and elevation changes (−0.341 to 0.138 meters) along Ruang's east and west coasts. These coastal morphological shifts may enhance the risk of tsunami generation, particularly under future scenarios involving flank collapse or continued deformation. The results show the potential of integrated remote sensing frameworks for rapid hazard assessment and early warning in volcanically active regions.