Landslide Risk Anticipation with InSAR
A large slope with potential risks to nearby infrastructure and safety was continuously monitored using InSAR technology starting in March 2022. Between March 25–28, 2025, a visible landslide occurred, causing significant structural impact. However, the historical InSAR data revealed clear signs of instability weeks in advance — meaning the event could have been anticipated and mitigated.

Objective
To demonstrate how recurring analysis of vertical and horizontal displacements using InSAR can anticipate real landslide risk several weeks before an event, allowing time for contingency or mitigation actions.
Analysis Focus
Vertical movement (subsidence and uplift)
Horizontal movement (lateral displacement)
Derived indicators - displacement rate, change in rate of movement, and total accumulated deformation
Key Findings
Alert Timeline
| Alert Type | Trigger Date | Time Before Event |
|---|---|---|
| Horizontal Alert | 17 Feb 2025 | 39 days |
| Horizontal Alarm | 1 Mar 2025 | 27 days |
| Vertical Alarm | 13 Mar 2025 | 15 days |
InSAR data provided up to six weeks of early warning before the landslide.
What Could Have Been Done
A regular (biweekly or monthly) analysis routine could have:
- Identified abnormal displacement and acceleration trends early
- Triggered timely inspection and mitigation plans
- Prevented structural failure and associated damage
Conclusion
This case study highlights:
- The reliability of InSAR monitoring in detecting real instability
- The combined value of horizontal and vertical displacement analysis for robust forecasting
- The importance of clear alert structures to enable proactive action
Value Proposition
Implementing a continuous InSAR monitoring system with periodic analysis:
- Enables true risk anticipation
- Reduces landslide impact dramatically
- Promotes a preventive rather than reactive approach to geotechnical safety