The M9.5 1960 Chile earthquake, the largest instrumentally recorded, caused over 2 m of coseismic subsidence in the Valdivia estuary, converting fluvial terraces into open water and, later, tidal marshes. We quantify the decadal‐scale post‐seismic recovery of these estuarine wetlands using historical aerial photography, Landsat/Sentinel imagery, GNSS‐derived vertical land motion, tide‐gauge and satellite altimetry sea‐level records, and dated sediment cores. Open water area expanded ∼8.8‐fold after the earthquake and has since contracted from ∼94 km ² in 1985 to 61 km ² in 2024, following a strongly linear trend ( r = −0.97) implying recovery to the pre‐earthquake fluvial extent by ∼2056. Interseismic uplift across the estuary (6.2–9.5 mm/yr) currently exceeds regional absolute sea‐level rise (∼2.3 mm/yr), producing a falling relative sea level that correlates strongly with vegetation expansion across tributary basins, indicating tectonic vertical land motion, rather than climate forcing, dominates wetland recovery at this timescale. Sediment accretion rates increase after subsidence and then decrease from subtidal to intertidal facies, reflecting the open water‐to‐marsh transition during interseismic emergence. A Monte Carlo projection combining vertical land motion, accretion, and IPCC sea‐level scenarios estimates the estuary will return to supratidal elevations by a median year of 2063 (5%–95% range 2047–2099), with coseismic subsidence magnitude and sea‐level rise dominating the uncertainty. These findings underscore the need to account for seismic‐cycle vertical land motion alongside climate‐driven sea‐level rise when assessing the long‐term resilience and carbon‐storage capacity of coastal wetlands in tectonically active subduction zones.

The tidal marsh and tidal flats in the intertidal zones of Chiloé, Chile are highly productive ecosystems that provide essential ecosystem services and preserve local biodiversity. However, they face increasing pressure from human activities. This study evaluated the cumulative risk of habitat degradation in Huildad Bay using the InVEST Habitat Risk Assessment (HRA) model. This study integrated spatial data on key stressors, including aquaculture, urban infrastructure, and road networks to develop the first high-resolution risk maps for these two coastal habitats. Rather than presenting a comprehensive assessment of the total cumulative anthropogenic risk for Huildad Bay, cumulative risk percentages are represented using selected stress factors that were geospatially mapped for this study. The results revealed a significant cumulative risk, with approximately 22% of the total area classified as medium risk. High-risk hotspots are minimal but ecologically critical (0.36% in tidal flats and 2.50% in tidal marshes) and strictly confined to the shoreline interface. An uncertainty interval analysis using Monte Carlo simulations (500 runs) quantified the parameter uncertainty of these estimates. Qualitative field corroboration using drone imagery visually identified physical proxies of degradation, such as hydrocarbon sheens, in model-predicted medium- to high-risk zones near the fishing pier. This research provides a defensible, spatially explicit risk-screening tool for local authorities. The findings highlight the urgent need for targeted management strategies, early-warning monitoring, and evidence-based public policies to ensure the long-term resilience and sustainability of these vulnerable coastal ecosystems.