Earthquakes are a very destructive and yet unpredictable manifestations of the Earth internal dynamics. They correspond to a rapid motion along geological faults, generating seismic waves as they propagate along the fault strands. The propagation of ruptures along faults induces dramatic stresses and deformation of the rocks hosting the fault, which become increasingly damaged (i.e, degraded) as multiple earthquakes occur along a fault over geological timescales. In turn, this damage of the off-fault rocks has an impact on the dynamic rupture processes: damage generation and earthquake rupture are coupled phenomena. A better knowledge of the dynamic damage processes can thus truly improve our understanding of the physics of earthquakes, and hence help to better predict strong motion and earthquake hazard. It is the goal of this proposal to investigate how dynamic ruptures can induce damage in the surrounding rocks, the specific characteristics of this damage, how it affects the rocks properties, and finally to build an earthquake rupture model which includes the couplings between rupture propagation and off-fault damage. The proposed approach is multidisciplinary, and includes: (1) field characterisation of naturally damaged samples around the San Jacinto fault in South California; (2) laboratory rock deformation experiments at very high deformation rates; and (3) the development of a numerical modeling approach, tested against experimental data, which will allow simulations of fully coupled earthquake rupture processes to be performed. By far the most challenging aspect of the study of dynamic damage is to perform rock deformation experiments at deformation rates and pressure conditions relevant to earthquake ruptures. To achieve this, our proposal includes the design and construction of a novel deformation apparatus which will allow high speed compression and decompression tests to be performed on rock samples. This apparatus will be unique in Europe and will cover an unprecedented range of deformation conditions.

Drylands store modest amounts of carbon in their soils and vegetation per unit area; however, as they cover 40% of the global land mass they store globally significant amounts of carbon overall. Rainfall is very variable between years, and these ecosystems respond rapidly to water availability. Therefore, carbon storage also varies greatly through time. Recent work has shown that dryland ecosystems may control variations in the global carbon cycle; however, there are significant uncertainties associated with understanding of carbon dynamics in dryland soils and vegetation, especially as climates change. Some researchers argue that drylands do not have the capacity to store or lose enough carbon to make any difference to the global amounts of carbon that are taken up by plants or soils, or lost to the atmosphere. Others argue that drylands may provide the 'missing-sink' in the global carbon cycle - helping to explain the stores of carbon needed to balance the global carbon budget, and that especially during wetter years, they have the capacity to store much more carbon than has previously been estimated. The current lack of consensus on the role of drylands in the global carbon cycle is hindering scientific ability to constrain the global carbon budget and understand future trends in the ability of the terrestrial carbon sink to mitigate climate change. This project will address this disagreement, providing robust analysis of existing data across a gradient of aridity and a range of plant types in a dryland region that contains the highest density of existing monitoring sites in the world. We will also undertake highly novel fieldwork, collecting new data which allow us to understand uncertainty in existing datasets that describe carbon storage and loss. We will then use new observations to evaluate which remotely sensed products, from existing satellite networks, are the most accurate at representing differences in carbon stocks in drylands. This element of the project is fundamental to understanding our planet, as it will enable more accurate global predictions of the carbon cycle and how this affects the global climate. Global modelling work argues that marginal, dryland ecosystems may control the global variability of carbon storage and loss and may also exert a profound control on the long-term trends of carbon storage and loss between the Earth and the atmosphere. This proposal will improve the empirical foundations of such model predictions. We contend that the predictions are likely to be true, but as yet have not been validated, nor understood well, in terms of the mechanisms that might underpin these controls. We will model the dynamics of vegetation in drylands, to test which vegetation models make the best predictions of growth and dieback, through wet and dry periods observed in the data that we collect in the first part of the project. Once we have established which vegetation models perform best, we will populate these models with appropriate parameters to predict how vegetation might respond to future climates, thus ensuring that the next step - to improve global model predictions of carbon loss and storage is made via a dialogue between empirical data collection and modelling. The project will deliver a fundamental improvement in our understanding of the carbon cycle in drylands, demonstrating empirically whether or not these landscapes have the capacity to control inter-annual variability and long-term trends in the land carbon sink. It will allow us to develop field techniques that can be exported to other landscapes, to constrain the uncertainty associated with measurements of ecosystem change. It will further allow us to understand and then recommend which globally available remote sensing products are best at characterising change in above-ground carbon stores in drylands. Finally it will permit us to make significant, data-based improvements to predictions of the global carbon cycle.

Society faces major challenges from viral diseases. The recent Zika and Ebola outbreaks are only two examples of the devastating impact of viral illnesses on human health, and viral pathogens infecting agriculturally important livestock and plants simultaneously reduce food production and inflict great annual financial losses worldwide. Viruses, however, also have positive impacts on health and ecology. They balance and stabilise our gut microbiome, preventing serious illnesses such as certain autoimmune diseases, and influence our climate owing to their roles in carbon cycling in the oceans. It is therefore paramount to better understand virus structure and function across the entire virosphere in order to control, and even take advantage of, viruses in medicine and biotechnology. I have demonstrated previously that mathematical approaches developed in tandem with experimentalists are drivers of discovery of functionally crucial structural viral features, revealing their novel functional roles in viral life cycles, and enabling their exploitation in therapy and biotechnology. Previously developed mathematical approaches were geared towards a specific major sub-group of the virosphere. In this research programme, I will both broaden and deepen the development of novel mathematical techniques. Working in close collaboration with leading experimental groups, at a larger scale, I will identify functionally important geometric viral features in a number of major groups of viruses. This will include: geometric strand assortment in multipartite viruses, such as the major agricultural pathogen Bluetongue virus; the assembly of retroviruses like HIV, with applications to the construction of virus-like particles from viral components as vectors for gene editing and therapy; and the structure and evolution of viruses important for the gut microbiome and marine ecology. By linking structural features with their functions, I will address open problems regarding drivers of evolution in one of the simplest yet most important groups of biological entities. This approach will unmask evolutionarily conserved functional features that can be used as novel targets in anti-viral therapy, for the development of novel safer vaccines or repurposed in bionanotechnology.

Seismic hazard assessment and understanding of continental deformation are hindered by unexplained slip-rate fluctuations on faults, associated with (a) temporal clusters of damaging earthquakes lasting 100s to 1000s of years, and (b) longer-term fault quiescence lasting tens to hundreds of millennia. We propose a new unified hypothesis explaining both (a) and (b), involving stress interactions between fault/shear-zones and neighbouring fault/shear-zones; however key data to test this are lacking. We propose measurements and modelling to test our hypothesis, which have the potential to quantify the processes that control continental faulting and fluctuations in the rates of expected earthquake occurrence, with high societal impact. Our aspiration is that cities and critical facilities worldwide will gain additional protection from seismic hazard through use of the calculations we pioneer herein. The background is that slip-rate fluctuations hinder understanding because they introduce uncertainty about whether specific faults are active or not. For example, a review in Japan of earthquake risk to critical facilities, such as the Tsuruga nuclear power plant (NPP), revealed a geological fault under a nuclear reactor (Chapman et al. 2014). The question that arose was whether the fault was active or not. Japan's Nuclear Regulatory Authority (NRA) has guidelines defining fault activity, and considered the fault under the reactor to be active, evidenced by faulting in sediments <~125,000 years in age. The Japan Atomic Energy Power Company (JPAC) disagreed, following study by an independent team of geoscientists. In 2014, the Tsuruga NPP remained closed due to ongoing debate between the NRA and JPAC, with similar debates ongoing for other NPPs. We suggest that defining fault activity as simply "active" or "inactive" is unsatisfactory because it is debatable even amongst experts. In fact a fault that has not slipped in many millennia may, in reality, not be inactive, but instead may simply have a low slip-rate, with the capability to host a damaging earthquake after a long recurrence interval. Our breakthrough is we think slip-rate fluctuations over both timescales (a and b) are a continuum, sharing a common cause involving interaction between fault/shear-zones. For the first time, we provide calculations that describe this interaction, quantifying slip-rate fluctuations and seismic hazard in terms of probabilities. We show that slip during an earthquake cluster on a brittle fault in the upper crust occurs in tandem with high strain-rate on the viscous shear-zone underlying the fault. This deformation of the crust produces changes in differential stress on neighbouring fault/shear-zones. Viscous strain-rate is known to be proportional to differential stress, so, given data on slip-rate fluctuations one can calculate changes in differential stress, and then calculate implied changes to viscous strain-rates on receiver shear zones and slip-rates on their overlying brittle faults. We provide a quantified example covering several millennia, but lack data allowing a test over tens to hundreds of millennia. If we can verify our hypothesis over both timescales, through successful replication of measurements via modelling, we will have identified and quantified a hitherto unknown fundamental geological process. We will study the Athens region, Greece, where a special set of geological attributes allows us to measure and model slip-rate fluctuation over both time scales (a and b), the key data combination never achieved to date. We know of no other quantified explanation that links slip-rate fluctuations over the two timescales; the significance and impact of accomplishing this is that it has the potential to change the way we mitigate hazard for cities and critical facilities. Chapman et al. 2014, Active faults and nuclear power plants, EOS, 95, 4

Turbidity currents are the volumetrically most import process for sediment transport on our planet. A single submarine flow can transport ten times the annual sediment flux from all of the world's rivers, and they form the largest sediment accumulations on Earth (submarine fans). These flows break strategically important seafloor cable networks that carry > 95% of global data traffic, including the internet and financial markets, and threaten expensive seabed infrastructure used to recover oil and gas. Ancient flows form many deepwater subsurface oil and gas reservoirs in locations worldwide. It is sobering to note quite how few direct measurements we have from submarine flows in action, which is a stark contrast to other major sediment transport processes such as rivers. Sediment concentration is the most fundamental parameter for documenting what turbidity currents are, and it has never been measured for flows that reach submarine fans. How then do we know what type of flow to model in flume tanks, or which assumptions to use to formulate numerical or analytical models? There is a compelling need to monitor flows directly if we are to make step changes in understanding. The flows evolve significantly, such that source to sink data is needed, and we need to monitor flows in different settings because their character can vary significantly. This project will coordinate and pump-prime international efforts to monitor turbidity currents in action. Work will be focussed around key 'test sites' that capture the main types of flows and triggers. The objective is to build up complete source-to-sink information at key sites, rather than producing more incomplete datasets in disparate locations. Test sites are chosen where flows are known to be active - occurring on annual or shorter time scale, where previous work provides a basis for future projects, and where there is access to suitable infrastructure (e.g. vessels). The initial test sites include turbidity current systems fed by rivers, where the river enters marine or freshwater, and where plunging ('hyperpycnal') river floods are common or absent. They also include locations that produce powerful flows that reach the deep ocean and build submarine fans. The project is novel because there has been no comparable network established for monitoring turbidity currents Numerical and laboratory modelling will also be needed to understand the significance of the field observations, and our aim is also to engage modellers in the design and analysis of monitoring datasets. This work will also help to test the validity of various types of model. We will collect sediment cores and seismic data to study the longer term evolution of systems, and the more infrequent types of flow. Understanding how deposits are linked to flows is important for outcrop and subsurface oil and gas reservoir geologists. This proposal is timely because of recent efforts to develop novel technology for monitoring flows that hold great promise. This suite of new technology is needed because turbidity currents can be extremely powerful (up to 20 m/s) and destroy sensors placed on traditional moorings on the seafloor. This includes new sensors, new ways of placing those sensors above active flows or in near-bed layers, and new ways of recovering data via autonomous gliders. Key preliminary data are lacking in some test sites, such as detailed bathymetric base-maps or seismic datasets. Our final objective is to fill in key gaps in 'site-survey' data to allow larger-scale monitoring projects to be submitted in the future. This project will add considerable value to an existing NERC Grant to monitor flows in Monterey Canyon in 2014-2017, and a NERC Industry Fellowship hosted by submarine cable operators. Talling is PI for two NERC Standard Grants, a NERC Industry Fellowship and NERC Research Programme Consortium award. He is also part of a NERC Centre, and thus fulfils all four criteria for the scheme.