Modeling the Contribution of Land Subsidence to Water Level Change in Former Boneng Mine Site Using Multi-Temporal InSAR

Abstract. There are 27 recorded abandoned mines within the Philippines. Unfortunately, there is insufficient data regarding the history, features, and current impact of abandoned mines on the locale. This study proposes the usage of remote sensing techniques as an alternative for quantifying and modeling the occurrence of land subsidence near mine pit lakes using the former Boneng mine (currently Lubo Lake) as the primary study area. Ground deformation values (averaged 3.3 mm/yr vertical velocity for the entire site) from 2015 to 2021 were derived from Sentinel-1 images. Lake water level changes (averaged at -0.665 m/yr for summer seasons and 1.613 m/yr for rainy seasons) were estimated through Normalized Difference Water Index (NDWI) calculations, vectorization, and geometric transformations. The contribution of land subsidence to the lake water level, along with other geologic and climate features, and predicted changes were modeled using a Generalized Additive Model (GAM). Land subsidence was found to affect the water level changes of the lake. However, its significance and overall predicted effect could not be generalized into a pattern or trend by the GAM.