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.

More information

Access the full paper:

Funding

This is work is funded by the 51ÁÔÆæ 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.

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 and floods triggered by earthquakes pose a great threat to human life and infrastructure. Currently, research into mitigation of these natural hazards has focused on events triggered during or shortly after earthquakes; for example, the failure of a slope shortly after a seismic event.

However, the long-term seismic effects that cause unstable landslides to accelerate without immediate failure are largely neglected. A new project, ‘Advancing knowledge of multi-hazards processes and their impact’ (AMHEI), aims to fill this research gap by looking at slope dynamics following a major earthquake and how these processes can also affect flood hazards.

There is currently little research into earthquakes affecting landslides and flooding in the longer term. We are excited to be able to utilise latest satellite technologies to better understand the relationships between these hazards.

Alessandro Novellino, BGS Remote Sensing Geoscientist.

AMHEI will use the latest satellite technologies, includingInterferometric Synthetic Aperture Radar(InSAR) combined with artificial intelligence techniques, to map and identify relationships between natural hazards in Turkey, using the February 2023 earthquake as a case study.

Funded by the European Space Agency, the project will be led by Alessandro Novellino, a remote sensing geoscientist at BGS, in collaboration with colleagues at the Faculty of Geo-Information Science and Earth Observation at the University of Twente (Netherlands) and the University of Bergen (Norway).

Research led by a BGS scientist has revealed that an estimated 1.9 to 2.7 million people in the Bandung metropolitan region of Indonesia would be exposed to high levels of ground shaking from an earthquake on the nearby Lembang Fault.

Over the past five years, Ekbal Hussain, a remote sensing geoscientist at BGS, has worked alongside scientists in Indonesia to research and produce deformation maps for the Bandung metropolitan region. To do this, they used a combination of data from satellites and GPS measurements made around the fault.

Bandung is the capital of West Java, Indonesia, and has a population of approximately 8.4 million people. The centre of the city lies less than 10 km south of the Lembang Fault, a major fracture between two blocks of rock in West Java. Although there are no documented records of large historical earthquakes, the Lembang Fault shows geomorphological evidence of significant earthquakes in the 15th century.

A fault slip rate is the average amount of earthquake energy accumulation each year; using different techniques, this had previously been estimated to either be between 1.95 to 3.45 mm a year or 6 mm a year for the Lembang Fault. This new study has found that the slip rate is 4.7 mm a year.

Using this new slip rate alongside previous studies, which estimated the recurrence period of large earthquakes on the fault at between 170 and 670 years, it can be estimated that the magnitude of an earthquake will be between 6.6 and 7.0. If such earthquakes were to occur on the fault today they would expose approximately 1.9 million to 2.7 million people within the Bandung metropolitan region to high levels of ground shaking, greater than 0.3 g, or 30 per cent of the strength of gravity.

The research highlights the importance of not forgetting local crustal faults located near large urban centres, which also pose a high risk to communities.

In Indonesia, the perceived risk of earthquakes is from large events on the subduction zone. However, in this paper, we show that shorter faults like the Lembang Fault, located much closer to major cities, can also be extremely dangerous.

Ekbal Hussain, BGS Remote Sensing Geoscientist.

Funding

This is work is funded by the UK National Capability ‘Geoscience to tackle global environmental challenges’ 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.

More information

Access the full paper:

As climate change affects the globe, the regional impact in southern Africa is that of a drying climate with more frequent droughts (Dai, 2012). Combined with an increasing population, this poses challenges to future food supply (van Ittersum et al., 2016).

Conservation agriculture (CA) is a promising tool to help combat the factors affecting food security in the region. This is an agricultural technique consisting of minimal soil disturbance (no tillage), mulching the soil with crop residues (the remains of the crop after harvest), and crop rotation and/or intercropping to diversify the system (FAO, 2016). CA has been shown to increase both yields and the resilience of crops to drought when compared to conventional agricultural methods and has been found to increase water infiltration into soils, reducing runoff and erosion (McGarry et al., 2000; Palm et al., 2014; Pittelkow et al., 2014; Steward et al., 2018; Thierfelder and Wall, 2009; Verhulst et al., 2010).

Whilst we are aware that CA can improve yields and drought tolerance and that it can influence water infiltration, little is known about hydrodynamics below the ground surface, i.e. the way the water moves through and is stored within the soil profile and how it travels to the groundwater table. The , described in detail in a blog by project lead Prof Murray Lark, aims to provide some answers to fill this knowledge gap.

Questions the project hopes to answer include:

• how does CA affect the quantity of water stored in the soil profile?
• how is water uptake by crops influenced by CA?
• how does CA alter recharge rates for groundwater?

My own research is on near-surface geophysics, specifically developing and applying electrical resistivity tomography (ERT), a ground imaging technique. ERT entails the use of an instrument to pass an electrical current through the ground via cabling and metal electrodes, and the measurement of voltages produced by the resultant electrical field in the vicinity of that current. By collecting many measurements in one dataset and processing the data with specialised software, it is possible to model (or image) the electrical resistivity of the subsurface in either two or three dimensions and at a high spatial resolution.

The resultant electrical resistivity models may be influenced by factors such as soil composition, porosity and water content. Through the repetition of ERT measurements over time, it is possible to see the changes in resistivity of the ground; assuming the soil composition has remained constant, any difference in resistivity is likely caused by variations in the water content of the soil, therefore it is possible to image soil moisture content over time (hydrodynamics). This ability to study the hydrodynamics of soils makes ERT ideally suited to helping to answer the research questions of the CEPHaS project.

At BGS we have developed a low-cost, low-power, ERT monitoring instrument called PRIME. Due to its low cost we have been able to purchase several instruments, enabling each to be permanently installed at an individual site. The low power requirements mean that we can install them in remote locations with just a solar panel and some batteries to provide the required energy. Consequently, we have been able to collect data with a higher temporal resolution than has been previously possible. We are collecting measurements twice daily in our three CEPHaS observatories in Zambia, Malawi and Zimbabwe.

In the CEPHaS project, we are using a combination of techniques to try to address our research objectives, through both the novel technique of ERT monitoring and more traditional methods:

• collecting weather data and monitoring the crops themselves to calculate evapotranspiration
• installing point sensors in the upper metre to monitor soil water content and soil suction (the capillary suction caused by the porosity of the soil).
• drilling boreholes to tens of metres and instrumenting them with piezometers to monitor the level of the groundwater table in order to study groundwater recharge

These traditional point-sensor methods provide high accuracy and a high frequency of measurements over time (temporal resolution), but their low spatial resolution means that they struggle to capture heterogeneities common in the subsurface and are not always able to show the cause of any rise or fall in groundwater levels.

We are using these more traditional methods together with ERT monitoring as the strengths and limitations of each complement one another.  While the collection of twice-daily measurements is pushing the boundaries for ERT monitoring, it is far less frequent than data collection by point sensors. Meanwhile, the high spatial resolution collected by ERT monitoring allows us not only to better understand heterogeneities between point sensors, but also to bridge the gap between the soil sensors in the upper metre and those sensors found in the boreholes at depth.

The aerial photograph in the video shows the agricultural test plots, while the coloured cuboids beneath the ground surface show the modelled electrical resistivity. Each of the resistivity cuboids are 1 m square in plan view, and 3.1 m deep. In the initial, static phase, warmer colours equate to higher resistivities, while cooler colours signify lower resistivities. After this, the modelled ERT shows changes in resistivity over time, with blue colours depicting decreasing resistivity and red showing resistivity increases. The decreases in the resistivity are caused by the wetting fronts created by several rainfall events penetrating to depth.

In addition to the research objectives of CEPHaS, the project possesses a very strong capacity-building element. The training and experience that has been provided throughout the project means that colleagues at the University of Zambia, Lilongwe University of Agriculture and Natural Resources and the University of Zimbabwe are amongst the most advanced users of PRIME technology outside of BGS. Not only this, but the equipment installed in the three CEPHaS observatories is to remain after the end of the project, allowing project partners to continue with important research and bid for new projects.

The CEPHaS project aims to answer important questions surrounding the hydrodynamics of CA by using complementary methods, both traditional and novel. With our findings, we want to assist policymakers and potential CA farmers with making informed decisions about the uptake of this promising agricultural method. We hope that the dissemination of our findings, and the increased research capacity the project has built, will leave a legacy long beyond the project end.

My name is Alessandro and I am a remote sensing geoscientist at BGS. I use satellite data to map, monitor and model geohazards and part of my job consists of working during disaster response activities.

The key to successful emergency response is quick and effective early action. This is only possible if the right information is available in the right place, in the shortest time possible. Because we are now in the ‘Golden Age’ of spaceborne Earth observation (EO), satellite data is providing users with an unprecedented wealth of data¹ that is stimulating the growth of processing services² and novel methodologies³ while also improving our capability in disaster response situations.

I use EO data to identify damaged areas or potential cascading hazards following a disaster, which support civil protection authorities and international humanitarian communities in planning the logistics of relief action. I built most of my experience by leading EO activities for the processing of satellite data needed to reconstruct the evolution of volcanic activity that led to the Anak Krakatau 2018 collapse and tsunami^4,5.

Since then, I have become an authorised user of the . The charter is a worldwide collaboration, by which satellite data are made available for the benefit of disaster management. By combining EO data from different space agencies and commercial provides, the charter allows expertise to be coordinated for rapid response to major disaster situations. Equally importantly, the charter prompts participating space agencies to release satellite data at no cost.

To have an idea of the rapid growth in the use of satellite data from the disaster response community, the charter was activated 11 times in 2000, when the organisation was first established, rising to 55 times in 2020. My most recent work for the charter is related to the Nyiragongo volcano in the Democratic Republic of the Congo. The charter was activated⁶ less than a day after Nyiragongo eruption on 22 May 2021. At least 30 people died and to escape the dangers associated with the eruption, which occurred when fractures opened in the volcano side.

Soon after the activation I liaised with international space agencies (the European Space Agency, Japan Aerospace Exploration Agency and Argentina’s space agency CONAE) to coordinate the acquisition of tasked radar data over the volcano, resulting in a total of 18 images over the first two weeks. Differing from optical data, radar sensors can ‘see’ almost completely through clouds and volcanic plumes (Figure 1).

This gave me a unique opportunity to map the lava flows from space⁷ and estimate a total lava extent of about 9.4 km² with around 1100 infrastructure affected (as of the 27 May).  Although this is a preliminary analysis that has not yet been validated in the field (Figure 2), this piece of information was key for the BGS volcanology team to work in collaboration with the Goma Volcanological Observatory and assess eruptive volume calculations, vent identification, and probabilistic lava flow hazard assessments.

This Nyiragongo event shows how international initiatives provide organizations working on the front lines, like BGS, with the opportunity to increase the impact and effectiveness of our science by having quick access to EO data. However, I believe that the next step forward in the uptake of EO for disaster response lies in capacity-building activities, in an effort to help lower- and middle-income countries use and benefit from space-based technologies not just at the response stage but, more importantly, during mitigation and preparedness, key phases to assess a region vulnerability and mitigate the risk.

Recently, a number of initiatives (UNOOSA, UNOSAT) are going into this direction and, in addition, NGOs are showing growing interest in space-based geographic information. I look forward to watching the progress.

References

International research published this week, illustrates the opportunities and challenges that robots and autonomous systems, known as RAS, could bring for urban biodiversity and ecosystems in the future.

51ÁÔÆæ Principal Modeller Dr Andrew Barkwith was part of a global team who contributed to the paper , published in Nature Ecology and Evolution.

Led by the University of Leeds, the research explores emerging trends and likely future developments that could transform our natural environment and brings together views from 170 researchers and stakeholders from 35 countries around the world and from a variety of disciplines.

Robots and autonomous systems are technologies that can sense, analyse, interact with and manipulate their physical environment. They include automated vehicles, automated irrigation, smart buildings that mitigate heat stress, drones able to apply pesticides and wireless sensor networks used for monitoring.

The researchers highlight that technological innovations have altered the way in which economies operate and how people interact with built, social and natural environments.

RAS have already revolutionised how environmental data are collected and how species populations are monitored for conservation.

Researchers believe that too narrow a focus on technological advances may overlook other social, ecological and technological ramifications. 

It anticipated that around 7 billion people will live in urban areas by 2050. As mobile and sensor technologies advance, RAS are becoming more integrated within society with huge potential to enhance urban sustainability.

They have a large range of potential applications, such as autonomous transport, waste collection, infrastructure maintenance and repair, policing and precision agriculture.

However, we don’t have a particularly good understanding of how widespread uptake and use of RAS could impact biodiversity or ecosystems and it important to evaluate this.

This has been a very valuable project to be involved in as it highlights the different perspectives of researchers and stakeholders around the world and broadens our understanding of a rapidly emerging topic.

Dr Andrew Barkwith, BGS Principal Modeller.

It hoped this kind of horizon scanning will encourage innovation and facilitate proactive responses by researchers, managers, policymakers and other stakeholders.

The research illustrates the importance of understanding and responding to both positive and negative impacts of new technologies, to ensure an overall positive outcome, to avoid potentially detrimental and unintended consequences and to fully realise the benefits.

The findings strongly suggest that development and implementation of RAS should be aligned with environmental concerns.

For example, the automated management of hydrological systems could result in the homogenisation of water currents and timings of flow, disrupting the life cycle of flow-sensitive species.  

It clear the RAS offer unique opportunities that could benefit natural ecosystems, as well as how we interact with our urban environments and green spaces, around the world.

However, it is vitally important we gain a global perspective about these kinds of opportunities, challenges and impacts RAS present for the environment, early in the process, and that we continue with these kind of research opportunities to contribute insights from a geological perspective.

Dr Andrew Barkwith, BGS Principal Modeller.

Technology, such as robotics, has the potential to change almost every aspect of our lives. As a society, it is vital that we try to understand any possible side effects and risks of our growing use of robots and automated systems.

Although the future impacts on urban green spaces and nature are hard to predict, we need to make sure that the public, policy makers and robotics developers are aware of the potential pros and cons.

Dr Martin Dallimer, School of Earth and Environment at the University of Leeds.

The research was conducted as part of University of Leeds’ ‘Self Repairing Cities’ project, which aims to enable robots and autonomous systems to maintain urban infrastructure without causing disruption to citizens and was funded by the Engineering and Physical Sciences Research Council (EPSRC).

Andrew Barkwith is the lead for the 51ÁÔÆæ Smart Observing Systems (SOS) project, based at BGS headquarters in Nottingham.

51ÁÔÆæ is part of a multi-disciplinary team led by the University of Nottingham to develop a remote monitoring tool designed to help authorities manage public safety and environmental issues in recently abandoned coal mines.

The tool uses satellite radar imagery to capture millimeter-scale measurements of changes in terrain height. These measurements, when integrated with geological process models, can be used to monitor and forecast groundwater levels and changes in geological conditions deep below the earth surface in former mining areas. Ultimately this can help forecast where surface discharge of mine water may occur.

The study uses an advanced InSAR technique, called Intermittent Small Baseline Subset (ISBAS), developed by the University of Nottingham and Terra Motion Ltd and uses geological data provided by the BGS.

The method has been implemented over Nottinghamshire coalfields and the findings published in a paper ‘’ in the journal Remote Sensing of the Environment.

The team hopes to integrate results into an existing screening tool developed by the Environment Agency and Coal Authority to help local planning authorities, developers and consultants design sustainable drainage systems in coalfield areas, with potential to be scaled to coalfields across the UK.

The research was led by University of Nottingham PhD, David Gee and funded by the . ENVISAT and Sentinel-1 SAR data were provided by the with geological data by BGS and hydrogeological data by the Coal Authority.

Luke Bateson and Alessandro Novellino from the BGS Earth Observation and Geodesy capability have supported the geological interpretation and modelling of the InSAR results.

You can read more about the Interferometric Synthetic Aperture Radar (InSAR) technique from BGS Remote Sensing Geologist, Alessandro Novellino in ‘’, on the 51ÁÔÆæ blog.