Dynamic vertical land motion driven by climate and humans in the metropolitan Taipei Basin

This study investigates basin-wide vertical ground motion in metropolitan Taipei between 2009 and 2023 using geodetic data. Despite seasonal variations of ∼1 cm, we observed two major subsidence episodes: a 2-cm subsidence during 2009–2012 followed by complete recovery within a year, and a 2.5-cm subsidence during 2018–2022 with subsequent 2-cm rebound. Analysis of rainfall data, groundwater levels, and construction activities reveals that these deformation patterns correlate with both climate factors (drought and rainfall) and human activities (major construction projects). On the first order, the basin-wide deformation are controlled by climate, subsiding in dry years and uplift in wet years. However, areas undergoing intensive redevelopment exhibited 0.5–1 cm greater net subsidence than surrounding regions, indicating irreversible deformation in these zones due to the combined effects of construction-related groundwater extraction, increased surface loading from new buildings, and soil compaction during development activities. These findings highlight the complex interplay between natural and anthropogenic factors in urban ground deformation and emphasize the need for integrated water-management strategies in the context of climate change.