Millions of people in sub-Saharan Africa rely on hand-pumped boreholes (HPBs) for their water supply, but they are often unreliable, with frequent breakdowns and long repair times. Although there have been previous attempts to understand the difficulty of access to water in rural areas and the functionality of rural water supply systems, they have typically taken ‘siloed’ approaches and focused only on the technical or social factors that influence the supplies’ performance.

A and local researchers in both Africa and the UK, shows that the failure of HPBs is not simply due to a single issue, such as a lack of water or a technical failure: it is the result of a combination of complex social, technical and physical interactions. The study provides crucial information for decision makers across governments, non-governmental organisations (NGOs) and communities aiming to make rural water access more reliable.

The research found that the probability of any failure occurring is dominated by physical and engineering factors: a combination of water levels, the condition of the pump, aquifer yields, and borehole construction and configuration. The length of time the pump was out of action was dominated by social factors including demand, access to spare parts and financing. The project team, led by BGS, tested current HPBs and facilitated interviews and participatory mapping events with water users and managers across Ethiopia, Malawi and Uganda. Combining statistical patterns of HPB failure with lived community experiences led to a new conceptual model that represents the diversity of real-world water-management arrangements.

This paper invites those working in rural water supply in sub-Saharan Africa to consider infrastructure performance through an interdisciplinary lens. These complex interactions can be understood by using frameworks like the one proposed in this study to improve rural water supply performance, which is especially important as rural water systems evolve towards more complex solar and piped technologies.

It hoped that understanding these complex interactions around rural water supplies will help governments, NGOs and communities make rural water access more reliable and fairer for all.

Dr Donald John MacAllister, BGS Senior Hydrogeologist the paper lead author

This research provides valuable insights into the interconnected drivers of water service downtime. Its findings come at a critical time as groundwater will continue to play a central role in meeting future water demand and strengthening drought resilience. Acting on these insights will be essential to enhance public and private sector support for water service provision through stronger regulation, improved planning, increased financing and enhanced service management.

Vincent Casey, WaterAid

The paper is now available online:

51���� director of international geoscience, Maggy Heintz, and its director of national geoscience, Jonathan Ford, visited Santiago in Chile on 30 January to take part in a signing ceremony at the Ministry of Mining led by the Minister, Aurora Williams, and the British Ambassador, Louise de Sousa. The visit also tied in with the launch of Chile critical minerals strategy.

Scientists from both countries will work together to produce reliable geological information essential for the sustainable management of critical mineral deposits in Chile. They will exchange cutting-edge technology and advanced methodologies to further understand and promote sustainable practices around natural resources and how such work can contribute to the responsible development of Chile critical minerals sector.

Following on from the signing, the BGS team travelled to Calama and San Pedro de Atacama to sign a Memorandum of Understanding (MoU) between BGS and the National Institute of Lithium and Salars. This MoU will strengthen collaboration and increase hydrogeological understanding of sustainable brine management.

It is an honour to be formalising such an important strategic partnership between the UK and Chile. BGS looks forward to new, science-led collaboration between our two countries, as we explore our shared interest in sustainable mining practices and natural hazard mitigation.

Maggy Heintz, director of BGS International Geoscience

For the first time, a science team has directly documented and extensively sampled a freshened water system beneath the ocean floor off the coast of New England in the USA. This major discovery comes from the initial analyses of sediment cores recovered during the , led by Co-Chief Scientists Professor Brandon Dugan (Colorado School of Mines, Golden, USA) and Professor Rebecca Robinson (Graduate School of Oceanography, University of Rhode Island, USA.

The 872 m of core, retrieved from deep below the sea floor, is now being opened, analysed and sampled by the science team, during almost a month of intensive, collaborative work. The expedition scientists are working side by side during January and February 2026 to uncover new insights into the formation, evolution and significance of this newly documented, sub-seabed, freshwater system.

Five BGS staff members are part of the operational team: Jeremy Everest, Margaret Stewart, Raushan Arnhardt (expedition project managers), Mary Mowat (database manager) and Bentje Brauns (hydrogeology). Their role is to coordinate and support the science team to process the core according to IODP³ standards and protocols.

The goal of this expedition went far beyond collecting sediment cores. Scientists also set out to sample the water stored within the sediments, including from sandy layers that act as aquifers and from clay layers known as aquitards that usually keep the water in place beneath the sea floor.

Although roughly 70 per cent of Earth surface is covered by water, significant volumes of water also move and are stored below ground. Many coastal communities depend on land-based aquifers for their freshwater supply. What fewer people realise is that, in many parts of the world, the aquifers continue offshore and contain zones of ‘freshened’ water beneath the ocean floor. Scientists have known these offshore systems existed since 1976, but they have remained virtually unexplored until now. During the expedition, the science team successfully documented and sampled freshened water within a zone nearly 200 m thick below the sea floor.

We were excited to see that freshened water exists in multiple kinds of sediments – both marine and terrestrial. Freshened water in such different materials will help us understand the conditions that emplaced the water.

Prof Brandon Dugan, Colorado School of Mines, Golden, USA.

Further analyses, such as age models, conducted by the science team will help to find out where and especially when the water was placed here.

The cores contain sediment with a wide range of composition and ages. It was surprising to see sediment, not rocks, throughout the section. The sediment has not yet transformed into rock – I did not expect to see that and it will be an interesting component of our future work.

Prof Rebecca Robinson, Graduate School of Oceanography, University of Rhode Island, USA.

After a successful coring, sampling and downhole logging campaign last summer, the BGS team is incredibly excited to be supporting the science team to begin the scientific analysis the material collected. The cores have been safely held in their plastic liners since they were drilled out of the seabed and, at the Onshore Operation in Bremen, they are being opened and split, revealing the fresh split-core surfaces for the first time.

The BGS team are contributing to the detailed sampling and analysis of the cores that, when combined with the groundwater samples taken from the borehole, will improve our understanding of the development of the New England shelf and the freshened water reservoirs underlying it. It is such a satisfying moment, after years of effort to acquire the cores, to be rewarded with new data and insights in such an important and societally relevant subject.

David McInroy, marine geoscientist, BGS.

Shedding light on similar water aquifers around the world

The approach used during IODP³-NSF Expedition 501 will not only deepen understanding of offshore freshened groundwater systems off the coast of New England, but will also shed light on similar hidden water aquifers around the world. Because many coastal regions rely on groundwater for their freshwater supply, the expedition initial findings are highly relevant to society. The research will also reveal how nutrients such as nitrogen cycle through continental shelf sediments and how these processes influence the abundance and diversity of microbes living in these environments.

These goals align closely with the 2050 Science Framework for Ocean Research Drilling – one of the foundations of the IODP³ scientific programme. Ultimately, the expedition research will help to decipher how sediments and fluids cycle through the Earth system and improve our knowledge about sea level changes and freshwater flow beneath the seabed along our coastal shelves. “The researchers will continue to work on and with the samples to decipher more – for example, to date the groundwater more accurately which is critical to advancing our knowledge,” adds Rebecca Robinson.

Background

The expedition is a joint collaboration between the International Ocean Drilling Programme (IODP³) and the US National Science Foundation (NSF). The cores were retrieved during offshore operations between May and August 2025. For onshore operations the science team have met at the Bremen Core Repository, at MARUM – Center for Marine Environmental Sciences of the University of Bremen (Germany). “We greatly appreciate being able to conduct this advanced research at MARUM, supported by its world-class laboratories, exceptional facilities, and dedicated staff,” adds Brandon Dugan

The cores will be archived and made accessible for further scientific research for the scientific community after a one year-moratorium period. All expedition data will be open access in the IODP³ Mission Specific Platform (MSP) data portal in PANGAEA, and resulting outcomes will be published.

International approach

Forty science team members from 13 nations (Australia; China; France; Germany; India; Italy; Japan; the Netherlands; Portugal; Sweden; Switzerland; UK; USA) are taking part in this MSP expedition that consists of two phases: offshore and onshore operations. Offshore operations took place between May and early August 2025.

The expedition is conducted by the European Consortium for Ocean Research Drilling (ECORD) as part of IODP³, funded by IODP³ and the US National Science Foundation (NSF).

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Deep in the heart of the Borneo rainforest lies one of South-east Asia most important natural sites: the of Sarawak, Malaysia. Despite being home to one of the most diverse tropical rainforests on the planet, arguably the world heritage area most astonishing feature lies underground.

The caves of the Gunung Mulu National Park

Under the limestone ridge of Gunung Api lies the extensive Clearwater cave system. At over 260 km in length and with passages often exceeding 30 m in diameter, it is believed to be the world largest cave system by volume, and is a haven for local wildlife.

The nearby Deer Cave is home to an estimated three million wrinkle-lipped bats, which fly out of the cave each evening to feed, creating a stunning visual display. Cave swiftlets also fly many kilometres into the Clearwater cave system to make their nests, which are prized as a local delicacy and used to make bird nest soup. Lying in wait to try and catch them as they fly past are cave racer snakes, whilst an astonishing array of cockroaches, millipedes, crabs, crickets and spiders are sustained by the piles of guano (bat poo) that line the cave floor. The ecosystem featured in a series.

History of the caves

Caves are fantastic repositories of geological and archaeological data, preserving information that would otherwise be lost to surface erosion and degradation. They and the deposits they contain hold clues to past landscape change, allowing us to reconstruct how the Earth’s surface has changed over millennia.

The caves were first explored as part of a Royal Geographical Society expedition in 1978. Working in collaboration with the Sarawak Forestry Corporation and the national park, the has been exploring, surveying and undertaking research in the caves ever since. This includes caving expeditions led by Andrew Eavis, a veteran of the 1978 expedition.

Dating of stalagmites and cave sediments indicates the Mulu caves are up to three million years old. Other analysis of cave stalagmites has yielded a climate record spanning hundreds of thousands of years, whilst volcanic ash provides evidence of a massive volcanic eruption in the Philippines 189 000 years ago. More recent archaeological finds also provide evidence of human activity and burials in some of the caves.

Recent research within this incredible cave system led to a surprising discovery about the formation of the caves within it.

Unusual dissolution

One of the unusual aspects of the Mulu caves is the way the cave passages have been sculpted.  Most caves in the region are formed by the dissolution (dissolving or break down) of limestone by acidic water, primarily from rivers flowing through the cave. The action of flowing water on the limestone rock creates small asymmetrical scoops etched into the passage walls, called scallops. These are preserved on the passage walls even after the formative river has abandoned the passage, as the water finds new, lower routes through the rock. The scallops are of interest to scientists as they can be used to deduce past water flow, providing a record of how water flowed through the caves over time.

In the Clearwater cave system, typical scallops are present in the lower levels of the cave system, close to the present river. However, in the older, higher levels of the cave system, which have long since been abandoned by the river, they are strangely noticeable by their absence, having been dissolved away and replaced by unusual corroded and pitted rock architecture.

The passage walls are frequently eroded into small dissolution pots and coated with a weathered crust: analysis has shown these are composed of calcium phosphate minerals, which is highly unusual in caves. Corroded stalagmites are common, dissolved away like rotten teeth to reveal their internal growth rings. These features suggest some form of atmospheric dissolution of the passage walls and stalagmites has taken place in the time since the passage was abandoned by the underground river.

Comparison with other caves suggests these features are generally restricted to tropical cave systems. One of the key aims of recent Mulu expeditions has been to understand how these features form and why. A team of researchers led by BGS geologist Dr Andrew Farrant, cave microbiologist Prof Hazel Barton (University of Alabama), her PhD student J Max Koether and BGS isotope geochemist Dr Andi Smith set out to investigate what may be happening.

Caving and exploration

Undertaking cave research can be hard work. Sampling trips into a cave system over 250 km long takes time and, in some cases, involved making camp underground. It is hard, sweaty, sometimes muddy work, occasionally requiring ropes to climb up pitches or descend vertical drops. But the rewards are enormous: the caves are spectacular, with stunning formations, huge chambers and amazing biota.

The Clearwater streamway is probably one of the finest cave passages in the world. Not only is there the prospect of new scientific discoveries, but also the chance to explore new cave passages where no human has ever trodden. On one trip, the team crawled through a flat-out squeeze to emerge into an undiscovered chamber over 200 m long, 70 m wide and 50 m high (big enough to hold two Airbus A380 jets) and adorned with 20 m-high stalagmites.

Research

Complex ecosystems are a distinctive feature of tropical caves, driven by the daily input of guano from bats and swiftlets. Bats create large piles of pungent excrement beneath their roosts, whilst the swiftlets’ guano is dispersed more widely, sometimes kilometres into the caves. The teams’ initial hypothesis was that the guano was somehow implicated in creating the unusual dissolution forms and smooth walls seen in the caves. Initial analysis of the guano piles in the caves indicated that they are strongly acidic, comparable to stomach acid or lemon juice, with a pH as low as 1.9. This could account for dissolution beneath the guano pile, but not the pervasive dissolution features seen throughout the caves.

Further work on the microbiology of the guano showed that microbial breakdown of urea (from bats) and uric acid (from birds) generates significant quantities of ammonia and carbon dioxide, which are released into the cave air. Measurable plumes of ammonia can be detected in some caves; could this be responsible for the unusual features?

Attention turned to the weathered ‘paste’ seen on many passage walls. This turned out to be teeming with microbial life, in some places containing a higher microbial cell count than cultured yogurt. Analysis of condensation water droplets on the cave walls revealed extraordinarily high levels of nitrate (up to 7000 mg/l; for comparison, the UK drinking water standard is 150 mg/l), whilst drips feeding the stalagmites had little or no nitrate.

These observations suggest that ammonia released into the cave air by the microbial decay of bat and bird guano adsorbs onto water droplets on the passage walls and stalagmites. Here, microbes use the ammonia as a food source, producing nitrates, nitric oxide, nitrogen dioxide and nitric acid as byproducts. This acid dissolves the passage walls and stalagmites, removing the original dissolutional scallops and replacing them with a suite of biogenic dissolution features. It is estimated that, in some places, several metres of dissolution have occurred in just a few tens of thousands of years: geologically speaking, this is a very short time period.

Further work is ongoing to learn more about the microbial processes that occur within the guano and on the cave walls. The discovery of this novel mechanism of cave development has significant implications, such as how we interpret past environments from caves, the preservation of cave art, and the impact of this acidic environment on ropes and other caving equipment.

The great thing about the Mulu Caves Project expeditions is they have enabled us not just to explore new caves, but to do some amazing science too. One thing is clear from our work in the caves; the surface and underground environments are inextricably linked. There is much we still have to discover and one wonders what other secrets are waiting to be discovered beneath Gunung Api…

Publication

Our research has been recently published in the journal Geomorphology.

Farrant, A R, Koether, J M, Barton, H A, Lauritzen, S E, Pennos, C, Smith, A C, White, J, McLeod, A, and Eavis, A J. 2025. . Geomorphology, Vol. 483, 109822. DOI: https://doi.org/10.1016/j.geomorph.2025.109822

Thanks                 

Thanks go to Andrew Eavis and members of the Mulu Caves Project, the Sarawak Forestry Corporation and the Gunung Mulu National Park management and staff, without whom this work would not have been possible. Part of the research was funded by a NEIF steering committee grant to Andi Smith.

About the author

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.

51���� is to create a Memorandum of Understanding (MoU) in partnership with the State Service of Geology and Mineral Resources of Ukraine, after a meeting between BGS Director Karen Hanghøj and Yehor Perelyhin, Ukraine Deputy Minister of Economy, Environment and Agriculture. The document will establish a framework through which geological projects can be pursed.

Karen Hanghøj welcomed the agreement and the opportunities it brings with it.

51���� is built upon a history of strong collaborations that centralise the vital role of the subsurface in shaping resilient economies, sustainable environments and thriving societies.

I am excited by the potential to deliver innovative solutions and make a meaningful, positive impact on some of the most pressing challenges facing the world today, which will be unlocked through joint research and data exchange opportunities with Ukraine.

Dr Karen Hanghøj, BGS Director.

The talks with BGS took place as part of a visit to London that saw the Ukrainian delegation meet with the UK Government to explore the development of the critical minerals sector. Also on the agenda for the meeting was the creation of targeted training and professional development programmes for Ukrainian geologists and specialists, as investment in skills and scientific expertise are essential for the growth of strategic sectors.

Work will now focus on finalising the MoU, which will involve identifying priority projects related to the critical minerals sector and preparing the joint training programmes for Ukrainian geologists and specialists.

Current methods used to forecast aftershocks — secondary quakes that can prove more deadly than initial earthquakes — can take several hours or days. New machine learning models have now been developed that can forecast where and how many aftershocks will take place following an earthquake in close to real-time.

Researchers from BGS, the University of Edinburgh and the University of Padua created the artificial intelligence (AI)-driven forecasting tools. They were developed by training machine learning models on earthquake data from California, New Zealand, Italy, Japan and Greece, all parts of the world that regularly experience earthquakes.

The rapid forecasts produced by AI-powered tools could help authorities with decision making about public safety measures and resource allocation in disaster-hit areas. The team analysed the AI models’ ability to produce forecasts of how many aftershocks will take place within the 24 hours following earthquakes of magnitude 4 or higher. They compared the performance of their models with the most widely used forecasting system, known as the epidemic-type aftershock sequence (ETAS) model, which is used operationally in Italy, New Zealand and the USA.

While both model types show similar performance at forecasting aftershock risk, the ETAS model took much longer to produce results. As it involves running a large number of simulations, the ETAS model can take up to several hours or days on a single mid-range computer.

By training the AI tools on records of past earthquakes from regions with different tectonic landscapes, researchers say their models could be used to forecast aftershock risk in most parts of the world that experience earthquakes.

The research, published in Earth, Planets and Space, was supported by the European Union Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie SPIN Innovative Training Network.

This study shows that machine learning models can produce aftershock forecasts within seconds, showing comparable quality to that of ETAS forecasts. Their speed and low computational cost offer major benefits for operational use: coupled with the near real-time development of machine learning-based, high-resolution earthquake catalogues, these models will enhance our ability to monitor and understand seismic crises as they evolve.

Foteini Dervisi, study leader, PhD student at BGS and the University of Edinburgh School of GeoSciences.

The Jakarta Fault runs beneath the southern part of the capital city of Indonesia, Jakarta. Jakarta is one of the largest cities in the world, with a population exceeding 30 million in the metropolitan area. New research by BGS and Indonesian colleagues shows that this fault could generate a magnitude 6.5 earthquake, which would expose a large number of people as well as significantly important economic infrastructure to strong ground shaking.

Between 2019 and 2023, Indonesian scientists from the Institut Teknologi Bandung (ITB), National Research and Innovation Agency (BRIN) and the Geospatial Information Agency (BIG) collected ground movement data across the Jakarta Fault from a dense network of global navigation satellite systems (GNSS). These measurements revealed slow, millimetre-scale changes in ground movement occurring across the fault, which indicated energy accumulating that will need to be released, potentially in a future earthquake.

Geophysical modelling shows that ground movement is accruing on the fault at 3.2 mm per year, with the fault locked or ‘stuck’ down to at least 7.2 km. This accumulation has been happening for at least 210 years, which means that releasing it all now would result in a magnitude 6.5 earthquake.

While magnitude 6.5 earthquakes are not uncommon in Indonesia, they mostly occur under the ocean. The danger here is that the earthquake could occur in the middle of a densely built-up area like Jakarta, which means a much higher level of risk to life and infrastructure.

Dr Ekbal Hussain, remote sensing geoscientist at BGS and research co-leader.

The Jakarta Fault is a relatively newly recognised major tectonic fault on the Indonesian island of Java. It is a part of a broader fault system that cuts across most of Java, which, with a population of 157 million people, is the most densely populated island on Earth. Geophysical surveys conducted by BGS in the 1970s and 1980s, in collaboration with the Indonesian Geological Research and Development Center, helped identify this major tectonic structure for the first time, but its earthquake potential has remained unclear until now.

This research forms part of strategic UK/Indonesia research partnerships on geological hazard solutions, as outlined in a recently published White Paper, UK/Indonesia partnerships for advancing geohazard science for disaster risk assessment in Indonesia. The paper, co-developed by key Indonesian and UK hazard experts, presents a strategic roadmap to significantly reducing the impacts of geological hazards in the country. Importantly, it highlights the strength of UK and Indonesian science partnerships for delivering the best disaster resilience science.

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Funding

This is work is funded by the 51���� National Capability programme. The BGS and Indonesian researchers involved in this study are continuing their engagement with local government to address the hazard challenges raised in this work.