Wed 04 Mar 14:00: From Mantle Convection to Seismic Observations – and Back?: The Impact of Tomographic Resolution and Mineralogical Uncertainty on Reconstructed Mantle Evolution
Understanding the structure and evolution of Earth’s mantle is fundamental for constraining plate-driving forces, lithospheric stresses, and the long-term behaviour of the geodynamo. While the present-day thermodynamic state of the mantle can be estimated from seismic tomography and high-pressure mineral physics, putting tight constraints on temperature and chemical heterogeneity based on seismic observations still remains a major challenge. Geodynamic simulations, by contrast, provide theoretical predictions for mantle evolution. However, their quality depends on how well input parameters are known, and they are only meaningful when rigorously tested through geodynamic–tomographic comparisons or, ideally, by comparing secondary predictions to a broad range of Earth observations. In this talk, I will discuss recent developments and potential future directions aimed at providing a quantitative, physically consistent link between temperatures predicted by mantle circulation models (MCMs) and the wealth of information contained in seismic recordings. For example, using global 3-D seismic wavefield simulations and full-coupling free-oscillation calculations for the MCM -derived structures, synthetic traveltime residuals and seismic spectra can be computed that accurately capture the various non-linearities in the relation to the underlying temperatures. A critical component in this context is the effect of mineral anelasticity, and it is particularly important to account for the associated uncertainties when comparing synthetic and real data. In addition to this forward approach, geodynamic adjoint inverse modelling can be used to retrodict mantle flow back in geologic time starting from the present-day state derived from tomographic images. Key challenges therein include determining the resolution and uncertainty of the tomography used and how they affect adjoint-state reconstructions, as well as assessing how accurately temperatures can be recovered using uncertain mineralogical information. Addressing the scale discrepancy between fluid dynamic predictions and seismically imaged structures is crucial, as validating reconstructed mantle flow involves surface topography calculations that are highly sensitive to the tomographic input. To improve future retrodictions, we conducted synthetic experiments illustrating the challenges of integrating tomographic and geodynamic models. Using a reference MCM as the “true” structure, we employed the linear SOLA Backus–Gilbert framework to explore spatially optimised averaging kernels and noise-related uncertainties, proposing a workflow to identify ideal SOLA parameters for next-generation adjoint models. Furthermore, synthetic closed-loop experiments demonstrate that tomographic damping, spatial blurring, and simplified mineralogies cause substantial deviations from “true” temperatures, especially near phase transitions. When such temperatures are used to prescribe buoyancy in geodynamic simulations, the errors will amplify non-linearly, potentially activating incorrect phase transitions and significantly altering reconstructed flow trajectories.
- Speaker: Bernhard Schuberth (LMU Munich)
- Wednesday 04 March 2026, 14:00-15:00
- Venue: Wolfson Lecture Theatre.
- Series: Bullard Laboratories Wednesday Seminars; organiser: Alice Turner.
Wed 18 Feb 14:00: From icequakes to earthquakes: Using seismology across the scales to understand Antarctica’s glacial and subglacial environment
Seismic waves, generated both within the ice and by distant earthquakes, provide a unique window into some of the most inaccessible environments on Earth. In this way, cryoseismology, a rapidly evolving branch of seismology, offers a wide and exciting range of opportunities to study the glacial and subglacial environments of polar and mountain regions. Such observations are invaluable to our understanding of the cryosphere and for constraining how ice sheets will respond to a warming world. In this talk, I will present results from two studies that demonstrate how cryoseismology can be used to improve our understandings of the Antarctic Ice Sheet. Starting small, an array of accelerometers and geophones deployed on the Larsen C Ice Shelf in 2022 detected 108 icequakes originating from within the ice shelf. Correlations between icequake explosivity and tidal phase suggest that this micro-seismicity is predominantly driven by tidal infiltration and circulation of seawater in the ice. In combination with radar data, this novel observation provides new insight into how rifting, which eventually leads to the calving of large tabular icebergs such as A68 , can be controlled by the internal structure of ice shelves, with important implications for their long-term stability. At the other end of the scale, the growing number of seismic deployments across Antarctica has enabled the use of teleseismic earthquakes to investigate the continent’s lithospheric structure. These data, however, also record information about the basal conditions of the Antarctic Ice Sheet. By building on established receiver function and P-wave coda autocorrelation methods, both the extent of subglacial sediment and the presence of subglacial till can be constrained. Rutford Ice Stream provides an ideal natural laboratory for testing this approach, with complementary radar, active-source seismic, and drilling data allowing the seismic signatures of subglacial till to be robustly validated. This proof of concept is then extended across Antarctica, where mapping the distribution of this deformable till can inform ice sheet models and reduce uncertainties in the consequent sea-level rise predictions.
- Speaker: Aisling Dunn (BAS)
- Wednesday 18 February 2026, 14:00-15:00
- Venue: Wolfson Lecture Theatre.
- Series: Bullard Laboratories Wednesday Seminars; organiser: ChuanChuan Lu.
Tue 24 Feb 12:00: Melting of unconstrained particles
What do ice cubes in a cocktail have in common with butter on a pan? And what can both tell us about the physics of melting? Through controlled experiments we explored the melting dynamics of (nearly) unconstrained systems, and compared our results with direct numerical simulations and analytical predictions, and show that two idealised systems at the extremes of Reynolds number (i.e., lubrication approximation, and fully developed isotropic turbulence) can provide useful insights for complex, inaccessible phenomena.
- Speaker: Edoardo Bellincioni, University of Twente
- Tuesday 24 February 2026, 12:00-13:00
- 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.
Wed 11 Feb 14:00: What triggering can teach us on faults, fluids and slow slip
It is now well known that large earthquakes can trigger a wide range of slip events, from slow to fast, on active faults at very large distances. I will discuss instances of triggering following the 2023 Kahramanmaraş earthquakes in Turkiye, all pointing the finger on the role of fluids and granular dynamics using geodetic data and seismological records.
- Speaker: Romain Jolivet (École Normale Supérieure)
- Wednesday 11 February 2026, 14:00-15:00
- Venue: Wolfson Lecture Theatre.
- Series: Bullard Laboratories Wednesday Seminars; organiser: Adriano Gualandi.
Tue 24 Feb 12:00: TBC
Abstract not available
- Speaker: Edoardo Bellincioni, University of Twente
- Tuesday 24 February 2026, 12:00-13:00
- 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.
Wed 25 Feb 14:00: Exploring upper mantle flow with seismic anisotropy and mantle circulation models
Plate tectonics, and its familiar dynamic consequences including earthquakes, volcanoes, and even the surface topography, are intrinsically linked to convection in the silicate mantle below. Mantle convection is a complex thermochemical process by which hot material rises from the deep Earth to the surface via upwellings like plumes, and cold material is returned to the deep via subduction. Tomographic images of seismic velocity provide a snapshot of the thermochemical state of the mantle at the present day, but do not directly constrain dynamic processes such as deformation. Seismic anisotropy, the variation of seismic wave speed with direction, emerges as a result of the long-wavelength ordering of smaller features (such as crystals, fractures, or melt inclusions) and thus can give information about processes such as deformation and flow. Recent advances in seismic tomography have provided a global picture of anisotropy throughout the mantle, but quantitatively interpreting these for mantle flow requires models. The NERC -funded MC2 project has focused on building a large suite of mantle circulation models (MCMs) – convection simulations constrained by models of the Earth’s plate motion over the last 1 billion years – exploring a range of different parameters of mantle convection. It is providing a framework to compare these models to a broad spectrum of observations (seismic, geodynamic, geochemical, and geomagnetic). In this talk, I will outline how we are using these models to predict the seismic anisotropy resulting from the flow in the upper mantle in these models and comparing it to tomographic models of radial anisotropy. These comparisons demonstrate the influence of parameters including the radial viscosity profile of the shallow mantle and the core-mantle boundary temperature on the resulting anisotropy. The models we produce show a consistent discrepancy with the tomographic images at around 100 km below mid-ocean ridges, suggesting that the anisotropy observed here for the Earth cannot be explained by solely by the lattice preferred orientation of olivine. The most plausible alternative explanation for these signatures is the presence of deep melt below the ridges.
- Speaker: James Wookey (University of Bristol)
- Wednesday 25 February 2026, 14:00-15:00
- Venue: Wolfson Lecture Theatre.
- Series: Bullard Laboratories Wednesday Seminars; organiser: ChuanChuan Lu.
Wed 11 Mar 14:00: Seismotectonics of the Sumatra-Andaman region: insights from block modelling, high-resolution seismicity and seismic imaging
Convergence of the Indo-Australian and Eurasian plates along the Sunda subduction zone generates large earthquakes and tsunamis, exemplified by the 2004 Mw9.2 event. The subduction zone is a classic example of slip partitioning, where oblique convergence is partitioned between the megathrust and upper plate strike-slip faults. Upper plate faults are highly active, but their location and slip rates offshore are not well known. Additionally, the distribution of locked and creeping areas along the fault systems is not well resolved.
In this talk, I’ll share initial results from two studies investigating this tectonic system. We first use earthquake and GPS data to resolve fault slip rates through block modelling. We find several new features of the tectonic system, including the separation of the forearc into two independent blocks and a rapid slip rate of the Andaman-Nicobar fault in the Andaman Sea. Second, to better understand the geometry and behaviour of the Great Sumatran Fault in Northern Sumatra, we deployed 130 seismic nodes primarily for microseismicity detection and subsurface imaging. Our ~18 months of data reveal pronounced differences in seismicity along the fault. One segment appears to be creeping, with abundant shallow microseismicity and repeating earthquakes, while the other appears to have a locked upper crust.
- Speaker: Karen Lythgoe (University of Edinburgh)
- Wednesday 11 March 2026, 14:00-15:00
- Venue: Wolfson Lecture Theatre.
- Series: Bullard Laboratories Wednesday Seminars; organiser: ChuanChuan Lu.
Tue 17 Feb 12:00: Iron rain and iron snow in planetary interiors: insights from fluids experiments
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 so-called “iron rain”. The efficiency of chemical equilibration between metal and silicates controlled the initial temperature and composition of the Earth. Current parameterizations of the equilibration efficiency neglect the influence of planetary rotation after impact.
In a different planetary context, the icy moon Ganymede sustains an intrinsic magnetic field, likely generated by fluid motions in its iron-rich liquid core. Core evolution models suggest solidification proceeds from the outer boundary inward, producing dense, pure iron crystals that sink and remelt at greater depth. This process, referred to as “iron snow”, is thought to drive core dynamics that feed the magnetic field. Yet, it is commonly modeled as purely fluid convection, neglecting the presence and properties of solid particles.
- Speaker: Dr Quentin Kriaa (University of Cambridge)
- Tuesday 17 February 2026, 12:00-13:00
- Venue: Department of Earth Sciences, Tilley Lecture Theatre.
- Series: Department of Earth Sciences Seminars (downtown); organiser: .
Tue 03 Mar 12:00: Sulphur stories from the land, sulfur stories from the sea
The sulfur cycle is one of the main contributors to the control of O2 and CO2 atmospheric levels during Earth’s history. It interacts with both the carbon and oxygen cycles during weathering on land and diagenesis in the ocean. It is thus paramount to reconstruct accurately its variations in the past. To do so, sulfur isotope ratios in carbonates are an increasingly used archive, though major questions remains about (1) how sulfur isotope ratios are recorded in carbonate, (2) how well they are preserved and (3) what they mean.
I will present recent progress about how sulfate is incorporated in carbonates and a few examples of paleoenvironmental investigations, both on land and in the ocean. In continental environments, carbonates help retrace the origin of sulfur and understand the role of sulfuric acid in diagenetical processes. In oceanic sediments, reliably reconstructing past sulfur isotope ratios of seawater from carbonates will help to unpack various steps of diagenetic alteration and thus collect key information about the activity of microorganisms in deep ocean sediments.
- Speaker: Dr Guillaume Paris, University of Lorraine
- Tuesday 03 March 2026, 12:00-13:00
- Venue: Department of Earth Sciences, Tilley Lecture Theatre.
- Series: Department of Earth Sciences Seminars (downtown); organiser: Marie-Laure Bagard.
Mon 23 Feb 13:00: Constraining Carbon in Earth’s Mantle
In situ carbon isotopes are a powerful but under-utilised tracer of mantle processes, in part due to analytical challenges and lack of reference materials. In this talk, I present a new SIMS method for concurrently measuring carbon isotopes and carbon concentration in basaltic glass, enabling improved precision at low carbon concentrations and high spatial resolution. Applying this method to olivine-hosted melt inclusions, I first describe recent work constraining the convecting upper mantle, which yields a more positive and more tightly defined δ13C value than previously assumed, along with a lower organic burial fraction of carbon. I then present results from the Icelandic primordial mantle reservoir sampled at Miðfell, revealing anomalously heavy carbon isotopic compositions coupled with depleted incompatible element concentrations, potentially linking early core formation to modern mantle heterogeneity. Together, these results refine the mantle carbon baseline and deep carbon cycle and demonstrate how melt inclusions retain isotopic memory of Earth’s interior processes.
- Speaker: Dr. Joshua Shea, University of Cambridge
- Monday 23 February 2026, 13:00-14:00
- Venue: Harker 1, Dept of Earth Sciences .
- Series: Cambridge Volcanology Seminar; organiser: Natalie Deng.
Mon 09 Feb 13:00: Modelling explosive volcanic eruptions from proximal hazards to global climate disruption
Explosive volcanic eruptions have critical impacts on our environment and societies including local-regional scale devastation from pyroclastic flows and tephra fallout, regional-continental scale air pollution and airspace shutdown, and global-scale cooling of Earth’s surface. I will give an overview of my group research and how it contributes to understanding and managing these impacts. First, I will discuss how volcanic plume modelling, informed by laboratory experiments and observational databases, helps us understand the relationship between eruption intensity, atmospheric conditions and the height of injection of volcanic ash and gas into the atmosphere. Second, I will discuss how numerical models ranging from reduced-complexity models to full-blown Earth System Models with interactive stratospheric aerosols can help us constrain the radiative forcing and climatic impacts of volcanic eruptions. Using ice-core, geological and satellite records, I will apply these models to discuss volcanic impacts on climate from 8,000 BC to 2100. Last, I will bring together volcanic plume, aerosol and climate modelling to interrogate how ongoing climate change driven by anthropogenic activities will affect the life cycle of volcanic stratospheric aerosols, and whether we should expect more or less volcanic cooling as Earth warms.
- Speaker: Prof. Thomas Aubry, University of Oxford
- Monday 09 February 2026, 13:00-14:00
- Venue: Harker 1, Dept of Earth Sciences .
- Series: Cambridge Volcanology Seminar; organiser: Natalie Deng.
Wed 18 Feb 14:00: From icequakes to earthquakes: Using seismology across the scales to understand Antarctica’s glacial and subglacial environment
Seismic waves, generated both within the ice and by distant earthquakes, provide a unique window into some of the most inaccessible environments on Earth. In this way, cryoseismology, a rapidly evolving branch of seismology, offers a wide and exciting range of opportunities to study the glacial and subglacial environments of polar and mountain regions. Such observations are invaluable to our understanding of the cryosphere and for constraining how ice sheets will respond to a warming world. In this talk, I will present results from two studies that demonstrate how cryoseismology can be used to improve our understandings of the Antarctic Ice Sheet. Starting small, an array of accelerometers and geophones deployed on the Larsen C Ice Shelf in 2022 detected 108 icequakes originating from within the ice shelf. Correlations between icequake explosivity and tidal phase suggest that this micro-seismicity is predominantly driven by tidal infiltration and circulation of seawater in the ice. In combination with radar data, this novel observation provides new insight into how rifting, which eventually leads to the calving of large tabular icebergs such as A68 , can be controlled by the internal structure of ice shelves, with important implications for their long-term stability. At the other end of the scale, the growing number of seismic deployments across Antarctica has enabled the use of teleseismic earthquakes to investigate the continent’s lithospheric structure. These data, however, also record information about the basal conditions of the Antarctic Ice Sheet. By building on established receiver function and P-wave coda autocorrelation methods, both the extent of subglacial sediment and the presence of subglacial till can be constrained. Rutford Ice Stream provides an ideal natural laboratory for testing this approach, with complementary radar, active-source seismic, and drilling data allowing the seismic signatures of subglacial till to be robustly validated. This proof of concept is then extended across Antarctica, where mapping the distribution of this deformable till can inform ice sheet models and reduce uncertainties in the consequent sea-level rise predictions.
- Speaker: Aisling Dunn (BAS)
- Wednesday 18 February 2026, 14:00-15:00
- Venue: Wolfson Lecture Theatre.
- Series: Bullard Laboratories Wednesday Seminars; organiser: Alice Turner.
Thu 12 Feb 11:30: A Stefan-Graetz problem in the kitchen: cleaning by convective dissolution
One method of removing layers of unwanted material from a surface is to contact it with a solvent in which it will dissolve. The rate of dissolution is enhanced when the solvent is flowing, which is why dishwashers spray liquid around to both contact soiled plates with the aqueous cleaning solution and to generate falling films over the surfaces. [This is also why you should stack the dirty dishes properly!] In many cases a cleaning front develops, between soil-free and soiled regions. Modelling the front dynamics – a Stefan problem – is complicated by the rate of mass transfer being spatially non-linear – the Graetz problem. In this talk I will present recent experimental and numerical work on this topic, driven by an interest to improve the sustainability of cleaning-in-place of food processing equipment. No food will be cleaned during this talk, just lots of instant coffee.
- Speaker: Ian Wilson (University of Cambridge)
- Thursday 12 February 2026, 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.
Tue 24 Feb 11:30: TBC
Abstract not available
- Speaker: Edoardo Bellincioni, University of Twente
- Tuesday 24 February 2026, 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.
Fri 20 Mar 16:00: Topographically Generated Internal Waves in the Arctic Ocean Northward of the Critical Latitude
Abstract not available
- Speaker: Tianshu Liu
- Friday 20 March 2026, 16:00-17:00
- Venue: Tea Room, Old House.
- Series: Bullard Laboratories Tea Time Talks; organiser: David Al-Attar.
Fri 20 Mar 16:00: Title to be confirmed
Abstract not available
- Speaker: Tianshu Liu
- Friday 20 March 2026, 16:00-17:00
- Venue: Tea Room, Old House.
- Series: Bullard Laboratories Tea Time Talks; organiser: David Al-Attar.
Fri 13 Mar 16:00: Sensitivity of the Atlantic Meridional Overturning Circulation to Turbulent Diapycnal Mixing
Abstract not available
- Speaker: Kate Oglethorpe
- Friday 13 March 2026, 16:00-17:00
- Venue: Tea Room, Old House.
- Series: Bullard Laboratories Tea Time Talks; organiser: David Al-Attar.
Fri 06 Mar 16:00: Links between the lowermost mantle and the surface tested with a global map of ultra-low velocity zones
Abstract not available
- Speaker: James Aktins
- Friday 06 March 2026, 16:00-17:00
- Venue: Tea Room, Old House.
- Series: Bullard Laboratories Tea Time Talks; organiser: David Al-Attar.
Fri 27 Feb 16:00: Title to be confirmed
Abstract not available
- Speaker: Isabel Siggers
- Friday 27 February 2026, 16:00-17:00
- Venue: Tea Room, Old House.
- Series: Bullard Laboratories Tea Time Talks; organiser: David Al-Attar.
Fri 13 Feb 16:00: Applications of Bayesian inference to modern sea level
Abstract not available
- Speaker: Dan Heathcote
- Friday 13 February 2026, 16:00-17:00
- Venue: Tea Room, Old House.
- Series: Bullard Laboratories Tea Time Talks; organiser: David Al-Attar.