We aim to investigate transient, oscillatory and secular behaviour related to the dynamics of magma degassing and transport, and reflected in the levels of lava lakes, and in the composition and fluxes of emitted gases and in other geophysical and geodetic parameters. We will achieve this through detailed studies of the lava lakes of two contrasting "laboratory volcanoes" (Kilauea and Erebus). While both volcanoes host lava lakes, their magma properties differ significantly in terms of composition, crystal content, viscosity and degassing styles. This will enable us to examine a variety of volcanic phenomena and to develop and evaluate hypotheses pertinent to understanding the behaviour of many open-vent volcanoes around the world. Of particular importance to the project, we plan to acquire high-precision, high-temporal resolution and sustained measurements of lava lake level using an innovative and purpose-built radar instrument. This will be a novel adaptation of existing radar systems that have been used for other environmental applications, and builds from work on a prototype radar device that we are already designing and constructing ahead of our next field mission to Erebus volcano. The radar observations will be integrated, at the target volcanoes, with both operational and campaign measurements obtained from ultraviolet and infrared spectroscopy (for gas flux and composition), thermal imagers (for lake surface radiometry and velocimetry), gravimetry (for mass changes), continuous geodesy (to characterise ground deformation) and seismology. The new radar instrument will be integrated into the operational surveillance programme of the Hawaiian Volcano Observatory. Our focus in the first half of the project will be on perfecting and installing the radar instrumentation. In the second half we will capitalise on the incoming datastreams, integrate them with our own and other ancillary observations of the target lava lakes, and use time-series analysis to identify temporal evolution of lava lake cycles and secular phenomena, and leads and lags between different parameters (e.g., lake level, gas flux, gas composition). This will help to tease out relationships and feedbacks between degassing, rheology, lake geometry and eruptive style (e.g., explosive vs. passive degassing at Erebus). A key outcome of the project will be the development of hypotheses that explain the complex variations in lava lake level, gas flux and chemistry, mass change and surface deformation that we will have documented in the field. We expect the observed variability and contrasting dynamic regimes to represent both shallow (conduit and lava lake) and deeper (reservoir) processes. A key to the ethos of the project is its combination of expertise in radar instrumentation (UCL) and volcanology (Cambridge), and the close collaboration of UK project members with partners in the USA (the US Geological Survey-Hawaiian Volcano Observatory, and the Mount Erebus Volcano Observatory, which operates from New Mexico Tech.). This is an ambitious project through which we hope to transform aspects of our understanding of magmatic processes, thanks to the planned synergy of electrical engineering, field science, and sophisticated data processing and time-series analysis. We aim to recruit a PhD student through the Cambridge-NERC Earth System Science DTP to develop theoretical aspects of lava lake fluid dynamics. The student would work closely with the PI and named researcher (Dr. Nial Peters).

Explosions are a pressing and pervading threat in the modern world. Terrorist events such as the 2017 Manchester Arena bombing, large-scale industrial accidents such as the 2020 Beirut explosion, and the current conflict in Ukraine, have highlighted a key gap in our knowledge: we do not we do not yet understand how blast waves propagate and interact with multiple obstacles in complex environments. Accordingly, we cannot yet predict the loading from such events, and our ability to determine the consequences relating to risk, structural damage, and casualty numbers, is severely limited. Current numerical tools for predicting blast loads in complex environments are either overly simplistic, or physics-based numerical tools which have been hitherto developed in the absence of experimental validation data. Clearly, progress in this area is limited and will remain so until we have the ability to experimentally measure the output from explosions occurring in settings of varying complexity at varying scales. This proposal will see the development of an ambitious and unique experimental facility, MicroBlast, for ultra-small-scale studies of blast propagation in complex environments, making use of rapid prototyping and 3D printing to generate true replica test specimens. MicroBlast will be a new state-of-the-art apparatus for data-rich, high spatial/temporal resolution, multi-parameter, full-field measurements of blast loading using a combination of pressure sensors, stereo high speed video cameras, and medium-wave infra-red cameras. This facility will be a step-change in our ability to perform rapid, precision experiments in explosive load quantification; the blast equivalent of a wind tunnel or shaking table test. We aim to study the fundamental mechanisms governing blast load development in complex environments, and set the agenda for future research in this area. Are explosions in crowded environments repeatable and deterministic, or are they highly sensitive to small changes in input parameters? What are the consequences for numerical modelling tools and experimental design? We aim to develop the next generation of predictive approaches for blast in urban environments, and to collectively raise the scientific benchmark of load prediction and structural damage assessment.

The development of radiometric geochronology is one of the greatest triumphs of 20th century geoscience. Geochronology underpins the study of Earth history and puts fundamental constraints on the rate of biological evolution. Tremendous resources are invested in the development of sophisticated mass spectrometers capable of measuring isotopic ratios with ever increasing resolution and sensitivity. Unfortunately, the statistical treatment of mass spectrometer data has not kept up with these hardware developments and this undermines the reliability of radiometric geochronology. This proposal aims to create a 'software revolution' in geochronology, by building an internally consistent ecosystem of computer programs to account for inter-sample error correlations. These have a first order effect on the precision and accuracy of geochronology but are largely ignored by current geochronological data processing protocols. The proposed software will modify existing data reduction platforms and create entirely new ones. It will implement a data exchange format to combine datasets from multiple chronometers together whilst keeping track of the correlated uncertainties between them. The new algorithms will be applied to five important geological problems. 1. The age of the Solar System is presently constrained to 4567.30 +/- 0.16 Ma using primitive meteorites. The meteorite data are 'underdispersed' with respect to the analytical uncertainties. The presence of strong inter-sample error correlations is one likely culprit for this underdispersion. Accounting for these correlations will significantly improve the accuracy and precision of this iconic age estimate. 2. The Cretaceous-Palaeogene boundary marks the disappearance of the dinosaurs in the most notorious mass extinction of Earth history. We will re-evaluate the timing of critical events around this boundary using high precision 40Ar/39Ar geochronology. Preliminary results from other samples show that 40Ar/39Ar data are prone to strong (r^2 > 0.9) inter-sample error correlations, and that these have a first order effect on the precision and accuracy of weighted mean age estimates. A sensitivity test indicates that this may change the timing of the mass extinction by up to 200ka. 3. The 'Taung Child' is a famous hominin fossil that was discovered in a South African cave in 1924. It is considered to be the world's first Australopithecine, but has not yet been dated. We have a good unpublished U-Pb age of 1.99 +/- 0.05 Ma from a tufa collected above the hominid, and an imprecise upper age limit of 1.4 +/- 2.7 Ma on a calcrete deposit below it. Applying the new algorithms to the latter date will greatly improve its precision. This will be further improved with additional measurements, in time for the 100th anniversary of the Taung Child's discovery. 4. Depth profiling of the U-Pb ages in rutile and apatite provides an exciting new way to constrain the thermal evolution of lower crustal rocks. However, the laser ablation data used for this research are prone to strong error correlations that are not accounted for by current data reduction protocols. These protocols will be revised using the new software, permitting better resolution of the inferred t-T paths. (5) Radiogenic noble gases such as 40Ar (from 40K), 4He (from U, Th and Sm), and 129Xe (from 129I) are lost by volume diffusion at high temperatures. The revised regression algorithms implemented by the research programme will be applied to step-heating 'Arrhenius' experiments. This will improve the calculation of diffusion coefficients for these gas species, resulting in further improvement of (noble gas) thermochronology.