# From Deformation Monitoring to Mechanism Insight: Assessing Sudden Subsidence Risk via an Improved 2D SBAS-InSAR and Physical Modeling Approach

## TL;DR

The study improves subsidence monitoring in mining areas and identifies key mechanical thresholds to predict sudden ground collapse.

## Contribution

A refined 2D SBAS-InSAR technique and quantified mechanical thresholds for key strata rupture in coal mining.

## Key findings

- A refined 2D SBAS-InSAR method reduces monitoring error from 50 mm to under 20 mm.
- Critical width-to-depth ratios for key strata rupture are identified for different geological formations.
- The subsidence basin boundary angles are determined as 52.3°–58.6° (strike) and 44.3°–48.2° (dip).

## Abstract

What are the main findings?
The study successfully developed and validated a refined 2D SBAS-InSAR monitoring technique. This method significantly mitigates the influence of north–south horizontal displacement, thereby reducing the comprehensive error in measuring the mining-induced subsidence basin from 50 mm to less than 20 mm, and allows for the precise determination of its boundary angles.Through a coupled analysis of remote sensing data and physical simulation results, the research quantitatively identified the critical mechanical conditions—specifically the width-to-depth ratios of the mining panel—that lead to the sequential rupture of key strata at different levels (0.21–0.27 for Yan’an Formation, 0.53–0.82 for Zhiluo Formation, and 1.22–1.34 for Zhidan Formation).

The study successfully developed and validated a refined 2D SBAS-InSAR monitoring technique. This method significantly mitigates the influence of north–south horizontal displacement, thereby reducing the comprehensive error in measuring the mining-induced subsidence basin from 50 mm to less than 20 mm, and allows for the precise determination of its boundary angles.

Through a coupled analysis of remote sensing data and physical simulation results, the research quantitatively identified the critical mechanical conditions—specifically the width-to-depth ratios of the mining panel—that lead to the sequential rupture of key strata at different levels (0.21–0.27 for Yan’an Formation, 0.53–0.82 for Zhiluo Formation, and 1.22–1.34 for Zhidan Formation).

What are the implications of the main findings?
The proposed technical framework and the quantified thresholds provide a concrete theoretical foundation for building a predictive early-warning system. This moves the field beyond post-event description towards proactive risk assessment of sudden subsidence in mining areas with similar geological conditions.The findings offer critical scientific guidance for safe and green mining practices globally. By understanding the mechanisms and preconditions of key stratum failure, mining strategies can be optimized to prevent catastrophic ground collapse, thereby enhancing operational safety and minimizing environmental impact.

The proposed technical framework and the quantified thresholds provide a concrete theoretical foundation for building a predictive early-warning system. This moves the field beyond post-event description towards proactive risk assessment of sudden subsidence in mining areas with similar geological conditions.

The findings offer critical scientific guidance for safe and green mining practices globally. By understanding the mechanisms and preconditions of key stratum failure, mining strategies can be optimized to prevent catastrophic ground collapse, thereby enhancing operational safety and minimizing environmental impact.

Safe and efficient coal mining faces a global challenge in predicting sudden surface subsidence whose mechanisms remain unclear. This study, centered on deep coal seams in China’s Ordos Basin, examines the risk of abrupt subsidence controlled by high-positioned, ultra-thick, and weakly cemented key strata. We adopt an integrated “observation–experiment–model” paradigm. First, we construct a spatial decoupling model to analyze errors in 1D SBAS-InSAR monitoring, leading to a refined 2D method that reduces the three-dimensional monitoring error from 50 mm to under 20 mm. Based on this, the subsidence basin’s boundary angles are accurately determined as 52.3°–58.6° (strike) and 44.3°–48.2° (dip). Second, a large-scale physical simulation experiment visualizes the complete process of overburden failure up to the breaking of high-level key strata. Finally, by coupling remote sensing observations with experimental phenomena, a theoretical model is built to quantify the mechanical behavior of key strata, revealing the critical width-to-depth ratios for the rupture of the Yan’an Formation (0.21–0.27), Zhiluo Formation (0.53–0.82), and Zhidan Group (1.22–1.34). The research not only delineates surface subsidence morphology under special geological conditions but also answers the core questions of why subsidence occurs and when mutation may happen, thereby laying a theoretical foundation for a comprehensive early-warning model for mining areas worldwide.