Mapping the 2024-2025 Lewotobi Volcano Eruption Dynamics Using Sentinel-1 InSAR and Optical Data Wiguna Jaya A.A.P. (a*), Harintaka Harintaka (b)
a) Department of Geodetic Engineering, Faculty of Engineering, Universitas Gadjah Mada
Jalan Grafika No.2, Yogyakarta 55281, Indonesia
*anak.agung0300[at]mail.ugm.ac.id
b) Department of Geodetic Engineering, Faculty of Engineering, Universitas Gadjah Mada
Jalan Grafika No.2, Yogyakarta 55281, Indonesia
Abstract
Lewotobi Volcano in East Flores, Indonesia, experienced major eruptions between late 2023 and early 2025, significantly altering the landscape and threatening nearby communities. Understanding surface deformation before, during, and after these eruptions is essential for interpreting magmatic activity and enhancing hazard monitoring. This study uses Sentinel-1 SAR data processed with InSAR techniques to map ground deformation related to the 2024-2025 Lewotobi Laki-Laki eruption cycles. Ascending and descending orbit data from January 2020 to April 2025 were processed using ASF HyP3 and MintPy to generate time-series deformation maps. Additionally, Sentinel-2 optical imagery was used to detect lava flows and pyroclastic deposits. The results show inflation before eruptions in December 2023, November 2024, and March 2025, indicating magma accumulation, and deflation afterward, suggesting magma withdrawal. Persistent subsidence of up to -5.6 cm/year was observed on the northeastern to southeastern slopes, while uplift occurred near the summit. Deformation time-series from 15 points confirm the cyclic nature of activity, aligned with reported eruption phases. Sentinel-2 imagery supports the InSAR findings, showing visible lava and pyroclastic deposits in affected areas. This study demonstrates the effectiveness of combining free SAR and optical satellite data to monitor volcanic activity. The integration of InSAR and optical analysis enhances understanding of eruption dynamics and the relationship between surface deformation and subsurface magmatic processes. These findings may improve early warning systems and strengthen volcano monitoring in Indonesia and other tectonically active regions.
