Earth Sciences talks

The upper mantle beneath old, stable continents reveals puzzling seismic discontinuities within the cold and strong thermal boundary layer. This is unexpected, as tomographic models depict fast wavespeeds and low energy dissipation, offering no basis for sharp velocity gradients within the boundary layer. Resolving this paradox requires explaining the observations with mechanisms such as metasomatic alteration by volatile-bearing rocks or grain-scale solid-state processes. I present new constraints derived from scattered-wave imaging that significantly improve global coverage and depth resolution. Advanced denoising of body-waves reveals a sharp velocity reduction beneath two-thirds of all continents at 90 ± 20 km depth, best explained by sub-solidus grain-boundary weakening. In some regions, velocity drops are observed between 120 and 250 km, while in others, velocity increases occur at 150 ± 50 km. Across all cases, upper mantle discontinuities rarely extend beyond the continental heterosphere. Near continental margins and subduction zones, these features may indicate partial melting, while rare double discontinuities could reflect melt layers or tectonic remnants from continental assembly, paleo-subduction, or underplating. These findings provide crucial seismic clues for resolving the paradox of lithosphere discontinuities, offering new insights into the nature and dynamics of the thermal boundary layer beneath continents

• Speaker: Tolulope Olugboji, University of Rochester
• Wednesday 18 June 2025, 14:00-15:00
• Venue: Wolfson Lecture Theatre.
• Series: Bullard Laboratories Wednesday Seminars; organiser: Tom Merry.

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The Sulawesi subduction zone, having recently undergone the initiation of subduction, serves as an ideal natural laboratory for investigating the dynamics of subduction initiation in young ocean basins. Is the subduction process in this region “spontaneous” or “induced”? Why is the North Arm of Sulawesi rotating clockwise? Does the absence of a corresponding volcanic island arc represent a unique tectonic feature of the Sulawesi subduction zone, or is it a characteristic stage in the transformation of a young basin into an active continental margin? This study seeks to address these questions through a combination of numerical modelling and geophysical observations.

• Speaker: Miao Dong, Chinese Academy of Sciences
• Wednesday 11 June 2025, 14:00-15:00
• Venue: Wolfson Lecture Theatre, Bullard Laboratories.
• Series: Bullard Laboratories Wednesday Seminars; organiser: ChuanChuan Lu.

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Abstract not available

• Speaker: James Jackson
• Friday 13 June 2025, 16:00-17:00
• Venue: Tea Room, Old House.
• Series: Bullard Laboratories Tea Time Talks; organiser: David Al-Attar.

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In this talk I hope to show how I applied what I learned at the IEEF in my career as a consulting engineer. Of particular utility to me has been the idea of breaking a complex engineering problem into small tractable pieces. I am obliged to briefly introduce my company, Itasca International, and the type of work we do. I will show three examples: Potash is a water soluble rock made of potassium salts, it is economically important because its use as a fertilizer. In North America, potash is solution mined by circulating water that dissolves the rock. This is a rich problem that involves chemistry, fluid flow, heat transfer, and geomechanics. I will demonstrate some models that are used to help design solution mines, forecast production, and diagnose operational problems. Explosives are an inexpensive means to break and move rock for civil purposes like tunneling, road cut development, and open pit mine excavation. Rock blasting is a complex set of processes that span several orders of magnitude in time-scale, length-scale, and stress magnitude. I will describe some simple mathematical and numerical models that have helped understand blasting. Onshore wind energy is rapidly growing in the United States, partially as a consequence of the Inflation Reduction Act of 2022. During construction, the world’s largest mobile cranes are used to lift the nacelle and blades of turbines. There have been several high profile cases of these large cranes tipping over and being destroyed during construction. It is 2025, so every talk has to have something about machine learning now: I will describe the technical problem of soil bearing capacity failure and show how machine learning, via the concept of a surrogate model, has helped make wind turbine installation faster, safer, and less expensive.

Bio: Jason Furtney was a student at the IEEF from 2002 to 2006 after studying Geology at Edinburgh University. Since leaving the institute, Jason has been working as a consulting engineer for Itasca International, a geomechanics consulting and software company in Minneapolis, Minnesota.

• Speaker: Jason Furtney, Itasca International
• Thursday 03 July 2025, 11:30-12:30
• Venue: Open Plan Area, Institute for Energy and Environmental Flows, Madingley Rise CB3 0EZ.
• Series: Institute for Energy and Environmental Flows (IEEF); organiser: Catherine Pearson.

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At a late stage of its accretion, the Earth experienced high-energy planetary impacts. Following each collision, the metal core of the impactor sank as millimetric drops into a molten silicate magma ocean. The efficiency of chemical equilibration between these silicates and the metal core controlled the composition of the Earth controlled the initial temperature and composition of rocky planets, and hence the emergence of plate tectonics, the time when a solid inner core started to grow, or the driving of an early dynamo in the Earth’s core by exsolution of light elements.

In this talk I will present different experiments focusing on the interaction of settling particle clouds with their surrounding through entrainment, mixing and chemical reactions. I will first present experiments on inert clouds settling in a quiescent fluid. Then, I will discuss the implications of planetary rotation on the efficiency of chemical transfers inside particle clouds, largely disregarded despite the strong rotation rate of the proto-Earth that has been suggested by impact simulations.

• Speaker: Quentin Kriaa, Uni of Cambridge
• Thursday 12 June 2025, 11:30-12:30
• Venue: Open Plan Area, Institute for Energy and Environmental Flows, Madingley Rise CB3 0EZ.
• Series: Institute for Energy and Environmental Flows (IEEF); organiser: Catherine Pearson.

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Abstract not available

• Speaker: Jason Furtney,
• Thursday 03 July 2025, 11:30-12:30
• Venue: Open Plan Area, Institute for Energy and Environmental Flows, Madingley Rise CB3 0EZ.
• Series: Institute for Energy and Environmental Flows (IEEF); organiser: Catherine Pearson.

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Water quality in lakes is closely linked to hydrodynamics and is often dominated by thermal stratification which limits the exchange between the upper layers (called the epilimnion) and the deeper layers (called the hypolimnion). Consequently, the vertical redistribution of biogeochemical tracers such as dissolved oxygen and nutrients by convective overturning during winter is a key process in annual lake cycles. In deep lakes, convective cooling often does not reach the deepest layers. Furthermore, convective cooling is weakening due to climate change, motivating a good understanding of (i) alternative deepwater renewal mechanisms, and (ii) deepwater dynamics in large deep lakes in general. Understanding deepwater dynamics is crucial because of the role deepwater currents play in mediating water-sediment exchanges, hypolimnetic mixing, and horizontal and vertical transport.

In this talk, I will present results from several studies conducted in Lake Geneva, Western Europe’s largest lake (max. depth 300 m), combining field observations, 3D numerical modelling, and particle tracking. The first part of the talk will cover the dynamics and ecological implications of wintertime coastal upwelling and interbasin exchange and upwelling, highlighting their role in deepwater renewal. The second part of the talk will present recent findings on the importance of different vertical modes of rotationally-modified standing internal waves (i.e., Kelvin and Poincaré waves) on the deepwater dynamics in Lake Geneva, highlighting the impact of seemingly negligible but ever-present weak stratification in the deep hypolimnion on the vertical structure of higher vertical-mode Poincaré waves.

• Speaker: Rafael Reiss (University of Cambridge)
• Thursday 05 June 2025, 11:30-12:30
• Venue: Open Plan Area, Institute for Energy and Environmental Flows, Madingley Rise CB3 0EZ.
• Series: Institute for Energy and Environmental Flows (IEEF); organiser: Catherine Pearson.

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For large earthquakes to occur, seismic ruptures need to propagate long distances along-strike and overcome different types of barriers. Understanding how far an earthquake can propagate includes assessing the effectiveness of these barriers in stopping earthquakes, which depends on the characteristics of both the rupture and barriers. It also includes the evaluation of a portion of a fault to be ready to host an earthquake as it will depend, among other factors, on the energy accumulated since the occurrence of the previous large event. There is thus a time dependency.

In this talk, I will focus on both of these aspects. First, I will discuss about geometrical barriers, due to geometrical complexities along a fault (e.g. gaps and steps), within the framework of the rate-and-state friction law. Next, I will discuss about energetical barriers based on a recent extension of Linear Elastic Fracture Mechanics theory to elongated ruptures. The work presented here adopts a probabilistic approach and aims to integrate certain aspects of the physics of rupture propagation into seismic hazard analysis.

• Speaker: Speaker to be confirmed
• Thursday 05 June 2025, 14:00-15:00
• Venue: Wolfson Lecture Theatre, Bullard Laboratories.
• Series: Bullard Laboratories Wednesday Seminars; organiser: Adriano Gualandi.

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Abstract not available

• Speaker: Rafael Reiss (University of Cambridge)
• Thursday 05 June 2025, 11:30-12:30
• Venue: Open Plan Area, Institute for Energy and Environmental Flows, Madingley Rise CB3 0EZ.
• Series: Institute for Energy and Environmental Flows (IEEF); organiser: Catherine Pearson.

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Understanding how quickly, where, and why biodiversity is changing remains a key question in ecology. Observations show that the pace of change varies widely across different regions. Palaeoecological research contributes valuable insights by revealing long-term patterns and helping to interpret the effects of drivers such as human activity and erosion.

Drawing on examples from islands around the world, we examine how biodiversity has shifted significantly, particularly following human settlement and other environmental pressures. Our findings suggest that islands colonised within the past 1500 years tend to experience more rapid ecological changes than those settled earlier. We also explore the long-term introduction and spread of non-native species, along with the resulting trends in biotic homogenisation.

These examples show how standardised palaeoecological records can help create a more complete understanding of long-term changes in island ecosystems.

• Speaker: Sandra Nogué Bosch, Autonomous University of Barcelona
• Wednesday 04 June 2025, 17:30-19:00
• Venue: Latimer Room, Clare College.
• Series: Quaternary Discussion Group (QDG); organiser: wb350.

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James Sear, IEEF - Plumes in Turbulence

Ross Shepherd, IEEF — Efficiency of CO2 storage in aquifers

• Speaker: James Sear and Ross Shepherd, IEEF
• Thursday 29 May 2025, 11:30-12:30
• Venue: Open Plan Area, Institute for Energy and Environmental Flows, Madingley Rise CB3 0EZ.
• Series: Institute for Energy and Environmental Flows (IEEF); organiser: Catherine Pearson.

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Modern molecular science, best described as the convergence of (bio)chemistry, molecular biology, physics, and the transformative power of artificial intelligence, is paving the way in design of advanced materials for precision medicine. One of the most promising innovations are bio-nano hybrids, engineered systems that seamlessly integrate biomolecules into synthetic nanostructures to bridge the gap between biology and technology.

In this talk, we will delve into the design principles and biomedical applications of organic and hybrid nanomaterials, with a focus on their role in real-time detection of senescent (aged) cells and the role they play in early cancer detection, and targeted drug delivery.

Beyond the current applications, we will also explore how the next generation of bio-nano tools could redefine the future of biomedical nanotechnology, unlocking new possibilities for disease monitoring, intervention, and treatment. We will also examine the key challenges that must be addressed to streamline the translation pipeline from labs to clinic.

• Speaker: Prof Ljiljana Fruk ( Department of Chemical Engineering and Biotechnology)
• Thursday 22 May 2025, 11:30-12:30
• Venue: Open Plan Area, Institute for Energy and Environmental Flows, Madingley Rise CB3 0EZ.
• Series: Institute for Energy and Environmental Flows (IEEF); organiser: Catherine Pearson.

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To better understand current climate trends and extremes and their potential environmental impacts, annually resolved and absolutely dated proxy archives are required, but their quality and quantity decrease drastically back in time with only a few such records available before the Common Era. In this talk, we will learn from living and relict trees about climate and environmental conditions in eastern England and beyond from the present back to the mid-Holocene. I will introduce a vast, yet rapidly disappearing archive of thousands of exceptionally well-preserved subfossil oak and yew trunks in eastern England. Using dendrochronological, radiocarbon and isotopic dating, we anchor oak and yew tree-ring chronologies between 5,200 and 4,200 years ago. We further develop an eco-physiological model based on yew tree-ring stable carbon and oxygen isotopes to reconstruct mid-Holocene hydroclimate variability. We show that contrary to today’s climate-growth relationships, relatively dry soil and atmospheric conditions in the mid-Holocene favoured yew growth, while higher groundwater tables and wetter soils reduced ring width formation. We propose that yew woodlands disappeared around 4,200 years ago due to the combined effects of rapid sea-level rise in the North Sea, a prolonged negative phase of the North Atlantic Oscillation, and significant riverine flooding. These hydroclimatic and biogeographic changes in eastern England, together with independent evidence from pollen records and lake sediments, shed new lights on the yet debated 4.2 ka climate anomaly, typically associated with extreme drought in central Asia. Intriguingly, our new subfossil Fenland record implies unusually humid and stormy conditions for the North Atlantic/European region during this period.

• Speaker: Tatiana Bebchuk, University of Cambridge
• Wednesday 21 May 2025, 17:30-19:00
• Venue: Latimer Room, Clare College.
• Series: Quaternary Discussion Group (QDG); organiser: sr632.

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Abstract not available

• Speaker: Dr Benjamin Devenish (Met Office)
• Wednesday 28 May 2025, 13:00-14:00
• Venue: Small Lecture Theatre (SLT), Department of Geography .
• Series: Cambridge Volcanology Seminar; organiser: Matthew Morris.

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Abstract not available

• Speaker: Dr Benjamin Devenish (Met Office)
• Wednesday 28 May 2025, 13:00-14:00
• Venue: Small Lecture Theatre (SLT), Department of Geography .
• Series: Cambridge Volcanology Seminar; organiser: Matthew Morris.

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Abstract not available

• Speaker: Isabel Papanagnou
• Friday 16 May 2025, 16:00-17:00
• Venue: Tea Room, Old House.
• Series: Bullard Laboratories Tea Time Talks; organiser: David Al-Attar.

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Artificial Intelligence (AI) is transforming many fields, including geosciences and disaster risk management, by offering powerful tools for analysing complex systems and supporting critical decision-making process. However, as the complexity and potentially the predictive skill of an AI model increases, its interpretability — the ability to understand the model and its predictions from a physical perspective — may decrease. In critical situations, such as scenarios caused by natural hazards, the resulting lack of understanding of how a model works and consequent lack of trust in its results can become a barrier to its implementation.

This talk focuses on the emerging field of Explainable AI (XAI), which enhances the human-comprehensible understanding and interpretation of opaque ‘black-box’ AI models, can build trust in AI model results, and encourage greater adoption of AI methods in geoscience and disaster risk management. Drawing on recent research, it highlights how XAI can enhance the adoption of AI in this field and outlines key challenges, current trends, and promising directions for future integration of XAI into geoscience and disaster risk management applications.

• Speaker: Saman Ghaffarian, UCL
• Wednesday 14 May 2025, 14:00-15:00
• Venue: Wolfson Lecture Theatre, Bullard Laboratories.
• Series: Bullard Laboratories Wednesday Seminars; organiser: Lisanne Blok.

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Artificial Intelligence (AI) is transforming many fields, including geosciences and disaster risk management, by offering powerful tools for analysing complex systems and supporting critical decision-making process. However, as the complexity and potentially the predictive skill of an AI model increases, its interpretability — the ability to understand the model and its predictions from a physical perspective — may decrease. In critical situations, such as scenarios caused by natural hazards, the resulting lack of understanding of how a model works and consequent lack of trust in its results can become a barrier to its implementation.

This talk focuses on the emerging field of Explainable AI (XAI), which enhances the human-comprehensible understanding and interpretation of opaque ‘black-box’ AI models, can build trust in AI model results, and encourage greater adoption of AI methods in geoscience and disaster risk management. Drawing on recent research, it highlights how XAI can enhance the adoption of AI in this field and outlines key challenges, current trends, and promising directions for future integration of XAI into geoscience and disaster risk management applications.

• Speaker: Saman Ghaffarian, UCL
• Wednesday 14 May 2025, 14:00-15:00
• Venue: Wolfson Lecture Theatre, Bullard Laboratories.
• Series: Bullard Laboratories Wednesday Seminars; organiser: Tom Merry.

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Abstract not available

• Speaker: Professor Claire Horwell (Durham University)
• Monday 12 May 2025, 13:00-14:00
• Venue: Small Lecture Theatre (SLT), Department of Geography .
• Series: Cambridge Volcanology Seminar; organiser: Matthew Morris.

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Abstract coming soon

• Speaker: Saman Ghaffarian, UCL
• Wednesday 14 May 2025, 14:00-15:00
• Venue: Wolfson Lecture Theatre, Bullard Laboratories.
• Series: Bullard Laboratories Wednesday Seminars; organiser: Tom Merry.

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