Malaysia faces substantial risks from rainfall-triggered landslides driven by extreme meteorological conditions. Between 1961 and 2024, the country recorded over , causing significant loss of life and economic damages exceeding $1 billion. This figure is set to rise in the future due to climate change and rapid urbanisation, leaving low-income households and small businesses highly vulnerable.

Whilst there are existing systems for monitoring and mapping these landslides, researchers have found a critical gap in understanding the economic losses landslides cause and how they can be systematically assessed to support anticipatory and disaster finance solutions for hazard recovery.

The project, ‘Trigger index for rainfall-induced landslide risk assessment for enhanced resilience’ or TRIGGER, will see BGS and project partners and develop a landslide trigger index to support forewarning and rapid recovery. It will link past landslide losses with data on rainfall, ground conditions and the locations where communities and infrastructure assets are most exposed. This will help researchers and stakeholders to better understand the potential impacts of future extreme rainfall.

Through the TRIGGER project, we are linking up with colleagues in Malaysia to develop a landslide trigger index, to assist in better understanding the potential impacts of future extreme rainfall and help build resilience by enabling quicker recovery after disasters.

Dr Nikhil Nedumpallile-Vasu, BGS engineering geologist.

It is anticipated that this project will enable rapid, risk based, post-disaster financial relief, incentivise investment in resilient infrastructure, and support poverty reduction by protecting those most at risk. The project will offer a scalable model for other Indo-Pacific countries facing similar hazard profiles. 

Funding

The project is funded by the Foreign, Commonwealth & Development Office through its ‘’ programme, for innovative and effective climate adaptation and resilience projects.

Landslides cause significant disruption to the road and rail network across Great Britain and can lead to fatalities. Identifying active slope failure is a difficult task, as monitoring is costly and time consuming, especially at a national scale.

In collaboration with the University of Florence in Italy, BGS has used a new, semi-automated method that uses artificial intelligence (AI) to identify the slopes that are actively moving, highlighting areas potentially at risk.

Previously, BGS has used interferometric synthetic aperture radar, or InSAR, for monitoring landslides. One of the benefits of InSAR is the large amount of information available, especially at a national scale; but analysing all these data present a challenge for scientists. To help tackle this problem, we have developed a semi-automated method that combines a type of AI called machine learning with clustering tools. The benefit of this approach is that we can analyse data for the whole of Great Britain, which wouldn’t have been possible before.

Results from this recent analysis highlighted around 3000 slopes that showed consistent movement of over 2.5mm per year between 2018 and 2022. These actively moving slopes affect approximately 14000km of road and 360km of railway — 2.4per cent and 1per cent of the entire national network, respectively.

The slopes deemed unstable are not all linked to landslides. Rather, they show the areas that should be focused on not only for future landslide research and mapping but also for the effect on local infrastructure, such as buildings and roads.

Our new, semi-automated approach supports the work of landslide specialists and provides a practical solution for large-scale geohazard management. The tool has helped to classify more than 300000 slopes around the UK and has highlighted 3000 slopes that have moved in a four-year period.

Satellite InSAR data has enormous potential for understanding ground deformation, but its complexity and the volume of data require advanced automated tools to extract meaningful information. Our semi-automated method helps bridge this gap by identifying the most critical areas to focus on, enabling efficient monitoring and helping to prevent serious damage.

Dr Alessandro Novellino, BGS remote sensing geologist

This approach already provides a powerful disaster-management tool, allowing decision makers to quickly identify areas that are currently at risk from ground motion. By highlighting these vulnerable areas, it supports smarter prioritisation of detailed field surveys, maintenance, and mitigation strategies, reducing costs and improving safety.

Next steps will focus on refining this national-scale analysis by integrating more detailed topographical data, to move from identifying unstable slopes to automatically mapping individual landslides within those slopes. This will enable more precise classification of landslide types and extents and the likely triggering mechanisms. The results will be shared with key stakeholders, including local authorities, infrastructure owners and the Natural Hazards Partnership.

Camilla Medici, postdoctoral researcher at the University of Florence

The research paper, , is now available to read.

Landslides are an ongoing global threat that can lead to significant loss of life and damage to infrastructure. The paper, ‘’, describes a new geophysical method that enables a way of observing the subsurface to look for signs of underlying slope failure. Signs include moisture, suction and shear strength, which, when monitored, can provide earlier warning of hazard. The paper, led by BGS Honorary Research Associate (HRA) Arnaud Watlet with 16 co-authors — 10 of which are from BGS — has been awarded the 2024 British Geotechnical Association (BGA) medal for ‘meritorious contributions to geotechnical science or practice’.

An example of electrical resistivity tomography (ERT) data collected from the Hollin Hill Landslide Observatory, which generates 4D resistivity models, providing insights into subsurface structures. BGS © 51ÁÔÆæ.

The research was undertaken at BGS Hollin Hill Landslide Observatory in Yorkshire. The slope at Hollin Hill features slow-moving, clay-rich land, common to much lowland landslide activity across the world. Change was monitored at the observatory over a two-year period, focusing on the wettest parts of each season. Researchers used electrical resistivity tomography and low-frequency distributed acoustic sensing to investigate the integrity of unstable slopes at various scales. Combining resistivity and fibre optics to observe changes in ground composition allowed for better monitoring and evaluation of natural and engineered slopes.

Landslides triggered by rainfall can significantly affect communities and infrastructure. Predicting exactly where and when they’ll occur is challenging, as local factors like geology, slope orientation and ground moisture all play a role. Most landslide early warning systems mainly track slope movement or rainfall intensity but, by monitoring ground moisture, we can extend the warning period at particularly vulnerable locations.

Arnaud Watlet, BGS HRA and lead author of the paper.

We are delighted to receive the BGA award, which recognises the incredible work and strong dedication of our team to landslide prevention.

Jim Whitely, BGS HRA and co-author of the paper.

Scientists at the 51ÁÔÆæ (BGS) have published UK regional hazard maps revealing the most susceptible local authority regions around the country. The maps provide regional decision makers with an overview of the relevant hazards in their local area and provide an important indication of where more detailed hazard data may be required.

The analysis considers the occurrence of eight key geohazards relating to natural subsidence, the presence of the ground-gas radon, and the possibility of legacy mining in an area (excluding coal).

Regions in the south (Devon; Dorset; Hampshire; Kent; Surrey; Wiltshire; West Sussex) and north (Cumbria; North Yorkshire; Northumberland) of England are shown to be the most susceptible, with some regions affected by all eight hazards. The Outer Hebrides and Halton (south of Liverpool) were revealed to be the least susceptible, with exposure to three or fewer hazards.

Various geological properties and processes are associated with each hazard but the majority result in some form of ground movement, causing similar societal impacts and damage to infrastructure and homes. For example, collapsible deposits, compressible ground, running sands and shrink-swell subsidence can all result in damage to roads and pathways, breaks in utility pipes and damage to foundations and buildings. Former underground workings and soluble rocks can both cause larger underground cavities that may be prone to collapse, causing more significant and sudden movement and damage. Radon is the exception; it is a natural radioactive gas that can enter buildings from the ground and can increase the risk to human health where there is exposure to high concentrations.

Figures released by the show thousands of claims relating to ground movement such as subsidence are being made annually, costing millions of pounds to remediate. costs tens of millions pounds a year to repair and there are dramatic examples of and soluble rock collapses causing sudden and catastrophic damage to residential areas. Radon gas is linked to in the UK each year.

It is important to note that there are other active hazards such as river and coastal erosion affecting some local authority regions, not yet included in this study. 

To create these maps, BGS has simplified and summarised its geological information. In this generalised form they give an indication as to which geohazards are most prevalent per region. For a more detailed view of specific areas that are most prone to particular geohazards risks please visit the BGS data product webpages for mining hazards (non including coal), ground instability and radon gas to find out how to access higher-resolution data.

51ÁÔÆæ has compiled its most comprehensive and authoritative datasets in this way to provide the maximum support for a diverse range of stakeholders, ranging from regulators to policymakers and planners.

Presenting the data in this generalised manner provides a quick and convenient indication as to which geohazards are most prevalent by region, informing mitigation strategies and the acquisition of higher resolution data. We would encourage anyone interested in our hazard data to contact us or visit our dataset webpages for more information.

Katy Lee – BGS Product Portfolio Manager

The underlying BGS geohazard datasets from which these statistics are derived are each presented as five susceptibility classes per hazard. The summary maps shown here present statistics relating the upper three classifications which represent areas most likely to be impacted by the respective hazards. For the BGS GeoSure and mining hazard (not including coal) ground instability hazards these upper three classes represent areas where susceptibility to ground instability is possible, probable or known.  The BGS Radon Potential upper three classes cover 95 per cent of homes estimated to be at or above the threshold guideline for radon levels (200 becquerels per cubic metre).

For full details of the classification breakdown, please refer to the respective dataset product user guides:

• 51ÁÔÆæ GeoSure
• Mining hazard (not including coal)

Download the maps

• Geohazard susceptibility in each British local authority
• Most prevalent geohazards per local authority

Further information on the assessed hazards:

If you have any queries about the BGS data available to support hazard susceptibility assessments please get in touch (digitaldata@bgs.ac.uk) or visit our dataset webpages for more information.

To date, the real-time impact data that is needed to effectively forecast and monitor geological hazard events has been unavailable or incomplete. The FloodTags platform aims to fill this gap by using large language models (LLMs) to extract real-time and historic information from social media platforms (X; YouTube; Bluesky; Facebook; Instagram) and more than 150 000 online news sources. This collaboration is a step towards providing timely, ground-level insight into geological hazards around the world.

I am aware that many organisations around the world, including BGS, rely on the manual gathering of data from social media and the news during disaster events, and to update regional and national hazard inventories. This can add a significant time lag to relevant information being interpreted, particularly during natural disasters, which means any actions taken are also delayed. We have been working with FloodTags for some time now and are delighted to formalise our collaboration in this highly valuable area of research.

Catherine Pennington, BGS Engineering Geologist, landslides.

This collaboration marks a major step forward for FloodTags. Partnering with BGS brings us the scientific expertise and data to expand into landslides and other geological hazards. Their deep knowledge of earth science opens the door to new applications for our real-time media monitoring tools. Combined with the power of large language models, this collaboration allows us to jointly deliver fast and relevant disaster insights for both hydrological and geological hazards. This helps governments and emergency services in making more informed, evidence-based decisions.

Jurjen Wagemaker, founder of FloodTags.

As a first activity under the new Memorandum of Understanding, BGS and FloodTags are in Indonesia this week topresent the first version of HazTags, an LLM-powered platform for monitoring floodsand landslides using social and news media data. They will discuss long-term collaboration in Indonesia with:

• theIndonesian national research agency, BRIN
• Centre for Volcanology and Geological Hazard Mitigation (PVMBG)
• Indonesian Red Cross (PMI)
• Meteorology, Climatology and GeophysicsAgency (BMKG)
• Ministry for Public Works (PU)
• National Agency for Disaster Management (BPBD)
• Research Centre for Disaster Mitigation (ITB)

For more information, please contact BGS press (bgspress@bgs.ac.uk) or call 07790 607 010.

The World Landslide Forum takes place every three years, with the first meeting held in Tokyo, Japan, in 2008, and sees the participation of over a thousand researchers from all over the world. The aim of the forum is to create a common platform to promote cooperation between scientists, technicians and experts to develop collaborative strategies to reduce the risk of landslides worldwide.

The sixth World Landslide Forum, which was titled ‘Landslide science for sustainable development’, took place this year in Florence, Italy, from Tuesday 14 to Friday 17 November 2023.

It was announced at the forum that BGS has been designated as a World Centre of Excellence on landslide risk reduction, along with 15 other institutes.

It was a great honour for BGS to receive this recognition, which is testament to the hard work and excellent science undertaken by our landslides team.

Prof Jonathan Chambers, BGS Head of Shallow Geohazards and Earth Observation.

During the forum, the most important aspects relating to landslide research were addressed, following six thematic areas:

• monitoring and early warning
• modelling
• hazard and risk assessment
• mitigation techniques
• triggering mechanisms
• climate change

Loch Lomond is an iconic part of Scotland scenery, surrounded by a variety of landforms that tell us about the region glacial past. But hidden beneath the water is a less well-known landscape that also has an important story to tell. Researchers from BGS marine geoscience and landslides teams have been studying evidence for landslides that have occurred under the water since the retreat of the last glaciers in the area, around 11 700 years ago.   

Landslides around and in Loch Lomond

Onshore, evidence for landslides is quite common in steep highland areas like that around Loch Lomond. Most activity occurred soon after the last glaciers melted, when the landscape was adjusting to the removal of the thick ice cover after the end of the last ice age. Today, landslides are less frequent. They mainly go unnoticed in remote hills but can still be extremely disruptive when they coincide with infrastructure. 

Like their onshore counterparts, most of the underwater landslide activity appears to have occurred in the centuries immediately following glacier retreat and the underwater landscape is far more stable now. What we didn’t know is how this activity has affected the beds of lochs such as Loch Lomond. Using high-resolution, multibeam bathymetry and shallow seismic images collected by BGS, the team have detected evidence for widespread, underwater landslide activity in the loch itself. The locations of these past landslides can give clues to where underwater slopes may still be susceptible.

Recent activity

The team has found some evidence for more recent underwater landslide activity, too. They were particularly interested in a site known as Wade Bridge Bank. A report from the 1980s () describes a displacement of rockfill during the construction of an embankment for the A82. The embankment was completed and settled as planned before work began on the road, but little was reported on the impact that the earlier rockfill displacement had on the loch bed, primarily because high-resolution bathymetric survey technology didn’t exist at the time. 

51ÁÔÆæ research

This is where the new multibeam and shallow seismic data come in. The teams’ findings, published in the , show that the event likely initiated a series of underwater landslides travelling some 700 m and reaching almost halfway across the loch. Using information from the original report alongside interpretations from the new data, the teams were also able to run computer models to simulate the underwater landslide runout following the embankment displacement.

Work is continuing to build a database of past landslides in Loch Lomond, which we hope to extend to include other lochs and steep, near-shore sites in Britain. The techniques used in Loch Lomond also open excellent opportunities to investigate underwater slope processes at near-shore sites in steep glaciated settings. This is valuable not only in locations where infrastructure is planned along steep shorelines, but also where cables and pipelines associated with offshore energy could be severely damaged by such slope movements.

Further reading

• Carter, G D, Cooper, R, Gafeira, J, Howe, J A, and Long, D. 2020. . Geomorphology, Vol. 365, 107282. DOI: https://doi.org/10.1016/j.geomorph.2020.107282
• Finlayson, A, Nedumpallile-Vasu, N, Carter, G, Dakin, N, and Cooper, R.  In press. . Quarterly Journal of Engineering Geology and  Hydrogeology. DOI: https://doi.org/10.1144/qjegh2022-075
• Howison, J A, and MacDonald, A. 1988. . Proceedings of the Institution of Civil Engineers, Vol. 84(3), 497–518. DOI: https://doi.org/10.1680/iicep.1988.32

About the author

Dr Andrew Finlayson

Head of BGS Marine Geoscience

51ÁÔÆæ Edinburgh

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