Study on Land Subsidence Characteristics in Guangzhou Metro Protection Zones Based on Time-Series InSAR and Gis Spatial Analysis

Abstract

This study performs a spatiotemporal analysis and multi-dimensional attribution of land subsidence within Guangzhou's urban rail transit zones. Utilizing TS-InSAR (SBAS and PS-InSAR) on multi-source SAR imagery, we identified a “Stable North, Subsiding South” paradigm. While the urban core remains stable, extreme subsidence exceeding $280 ~\text{mm} /$ year persists in the rapidly developing Panyu and Nansha districts. Integrating GIS-based spatial overlay analysis, we quantified the driving mechanisms: a superposition of thick (15-40m) marine-terrestrial soft soils and anthropogenic pressures, including heavy building loads, groundwater extraction, and metroinduced socio-agglomeration. Tectonic faults further catalyze localized differential settlement. We propose a lightweight, intuitive analytical framework that bypasses the complexity of traditional geotechnical modeling. This approach provides essential spatial decision support for operational safety, early warning, and sustainable infrastructural planning in high-density deltaic metropolises.