Monitoring Soil Moisture to Detect Landslide & Rockfall Risk: Insights for Rail Asset Managers

Industry data consistently shows intense and prolonged rainfall to be a primary trigger for slope instability across transport networks. 

Globally, precipitation is responsible for the majority of landslide events, with statistics showing that precipitation followed by moisture change are the leading triggering factors (58%) of landslides worldwide. 

Railway-focused studies also confirm rainfall as the dominant driver behind embankment failures, debris flows, and rockfall. 

For rail asset managers, this elevates rainfall to a critical geotechnical risk factor. 

Short-duration, high-intensity events can rapidly alter ground conditions, reducing soil strength and destabilising rock masses with little visible warning. 

Climate trends are amplifying this: extreme rainfall events are becoming more frequent and are already causing increasing disruption and damage to rail infrastructure globally. 

As climate patterns shift and extreme precipitation becomes more frequent, the ability to continuously monitor ground response and detect subtle displacement trends becomes increasingly difficult. 

How water turns solid earth into a moving hazard

For rail asset managers, soil moisture is critical to slope stability, particularly along cuttings and embankments. 

As moisture content increases, matric suction in unsaturated soils reduces, leading to a loss of apparent cohesion and a corresponding drop in shear strength. In fine-grained soils, prolonged wetting can elevate pore water pressures and reduce effective stress, increasing the likelihood of shallow slips or deeper rotational failures. 

Cycles of wetting and drying can further degrade soil structure over time, weakening previously stable slopes and accelerating deterioration and the risk of landslides along rail corridors.

Rockfall hazards are also closely linked to moisture dynamics. 

In fractured rock slopes, water ingress along joints and bedding planes can reduce frictional resistance and promote block detachment, particularly during or after intense rainfall events. 

In colder climates, freeze–thaw action exacerbates this process, but even in temperate regions, repeated wetting can drive progressive loosening.

For asset managers, integrating continuous moisture and displacement monitoring—combined with predictive analysis—enables earlier identification of at-risk sections, supporting targeted intervention and reducing disruption to rail operations.

The blind spots of ground surveys 

Guarding thousands of miles of railway against geohazards heavily dependent on the changing weather conditions is a monumental challenge. 

With many monitoring approaches remaining quite static and inspection-led, risk scoring is driven by periodic site assessments and historical observations, without the frequent and consistent monitoring techniques needed to take account of daily rainfall and its effect on ground conditions. 

As a result, there is an inherent lag between the development of instability and its detection, meaning that evolving risks may not be captured until they become visible to the naked eye or operationally disruptive.

Other limitations of traditional monitoring include:

• High installation costs make equipping every mile financially unrealistic.

• Upkeeping installed sensors and instruments forces crews back into dangerous areas for repairs, battery swaps, calibrations and maintenance.

• The point-data trap means sensors only measure their exact location, easily missing potentially dangerous geohazards just feet away.

  
  

Because of these limitations, the early detection of hidden defects remains incredibly difficult. 

This poses the question: how exactly can we detect impending geohazards before they even start to move?

Watching from above: Detecting hidden track defects before they cause disruption 

Tapping into the power of satellite remote sensing, Geofem can pinpoint areas retaining moisture along your network through the introduction of continuous, network-wide monitoring and dynamic risk assessment. 

SAR satellites capture images of the Earth’s surface at regular intervals, typically every few days on a continuous basis. 

Geofem interprets the data captured by these satellites to provide you with actionable insights to optimise drainage, prioritise resources and plan maintenance. 

This allows asset managers to address hidden track defects before they cause delays or disruptions. 

A Geofem analysis revealing elevated soil moisture levels during satellite passes, highlighted by the lighter grey pixels and the bump in the graphical plots—an indicator of potential drainage issues or ballast fouling.

Key advantages of Geofem’s cutting-edge approach:

• Proprietary soil moisture algorithm: Power your decisions with Geofem’s technology, developed in partnership with the European Space Agency, delivering highly accurate and reliable insights.

•  Network-wide visibility: Identify risk across entire rail corridors—not just isolated locations.

• Long-term data insights: Access up to 10 years of historical data to uncover trends, detect patterns, and identify slow-developing issues often missed by conventional methods.

• Frequent, timely monitoring: Benefit from regular satellite revisits, enabling the early detection of changes in soil moisture and ground conditions.

• Engineering-led interpretation: Turn complex satellite data into clear, actionable insights, backed by Geofem’s expert analysis that supports confident, well-informed decisions.

• Cost-effective solution: Reduce the need for extensive on-ground sensor networks while maintaining high levels of accuracy and reliability.

A new era of predictive rail maintenance

As extreme weather intensifies, proactively managing the impact of climate change on rail infrastructure stability is no longer optional—it is essential. 

Geofem provides the missing layer that makes that framework continuous, predictive, and responsive.

By integrating SAR-derived displacement data into the monitoring framework, asset managers can move beyond static prioritisation to a dynamic risk model—enabling early detection of evolving ground conditions, from changes in soil moisture to slope movement that may signal instability.

Coupled with predictive analytics, satellite-based monitoring enables earlier intervention, improved risk prioritisation, and a deeper understanding of the triggers behind geohazards. 

This not only strengthens day-to-day decision-making but also builds a more resilient, future-ready rail network.

In this context, monitoring is more than observation, it is a calculated defence. By improving visibility across the entire network, including previously unflagged areas, asset managers can act sooner, reduce disruption, and ensure the ground beneath the tracks remains stable enough to keep passengers and operations moving safely.

Unlock the power of satellite remote sensing for soil moisture and discover how Geofem can support the seamless operation of your rail network. Contact the Geofem team today.