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This UKCCSRC (UK Carbon Capture and Storage Research Centre) Call 1 project involved the development, testing and validation of a two-fluid transient flow model for simulating outflow following the failure of high pressure CO2 pipelines is presented. The project made use of experimental data and used experimental data available from other UK/EC funded projects. The model developed accounts for thermal and mechanical non-equilibrium effects during depressurisation by utilising simple constitutive relations describing inter-phase mass, heat and momentum transfer in terms of relaxation to equilibrium. Pipe wall/fluid heat exchange on the other hand is modelled by coupling the fluid model with a finite difference transient heat conduction model. This paper describes the model, the details of its numerical solution and its validation as well as parametric analysis of relevant parameters. http://www.sciencedirect.com/science/article/pii/S1750583614002394, DOI: 10.1016/j.ijggc.2014.08.013. UKCCSRC grant UKCCSRC-C1-07.
Observed global seismograms used to study earthquakes in the Azores. The seismograms have been processed and then have been used to perform source inversions of the events.
International Ocean Discovery Program Expedition 363, planktonic foraminifera range chart data Planktonic foraminifera range charts indicating: Column A: Sample ID Columns B and C: sample interval Columns D and E: top and bottom sample depth Column F: Zone (Wade et al., 2011) [W11] Column G: Zone name
Processed SAR interferograms for the Wells, Nevada earthquake. Grant abstract: How do earthquakes happen? Understanding the nature of earthquakes is a key fundamental question in Geociences that holds many implications for society. Earthquakes are typically associated with a sudden release of energy that has slowly accumulated over hundreds to thousands of years, being strongly controlled by friction in faults buried several kilometers beneath our feet under quite extreme conditions. For example, the amount of heat produced in just a few seconds is such that it can dramatically change the nature of the fault zone near the sliding surface. Moreover, there is abundant evidence of substantial frictional weakening of faults (i.e., fault strength weakens with increasing slip or slip rate) during earthquakes. However, there are still many open questions related to earthquake source processes: How similar are earthquakes in different temperature-pressure conditions? What is the earthquake's energy budget, which controls the intensity of ground motions? What are the physical mechanisms responsible for fault weakening? Recent progress in seismological imaging methods, theoretical fracture mechanics and rupture dynamics simulations can help solve these questions. Huge volumes of freely available seismic and geodetic data from around the world now allow the routine calculation of earthquake models where earthquakes are typically described as single space-time points. Time is now ripe for systematically building robust, more detailed seismic models bearing information on earthquake's physics by using recently developed sophisticated modelling tools along with high-quality images of the 3-D Earth's interior structure enabled by high performance computing facilities. Moreover, it is now possible to model ruptures theoretically in detail using both analytical fracture mechanics calculations and numerical rupture dynamics simulations, and, for example, estimate the fault temperature during the rupture process, which is the most direct way to quantify friction. However, systematic quantitative links between these calculations and seismological observations are still lacking. This project addresses these issues through a coordinated effort involving seismology and rock mechanics aiming at estimating fault temperature rise during earthquakes from new macroscopic seismic source models. We will use advanced seismic source imaging methods to build a new set of robust kinematic, static and dynamic earthquake source parameters for a large selected set of global earthquakes (e.g., average fault length, width, rupture speed and time history, stress drop, radiated and fracture energy). These solutions will then be used as input parameters to estimate fault temperature using analytical and numerical rupture dynamics calculations. This will lead to an improved understanding of how local fault processes occurring at scales from few microns to tens of centimetres translate into macroscopic seismological properties, how energy is partitioned during earthquakes and which are the mechanisms responsible for fault weakening. Ultimately this project will shed new light on many basic questions in earthquake science such as the similarity of earthquakes in different P-T conditions and the potential geological record left by ruptures (e.g., melt). More broadly, this project will benefit hazard models and any studies relying on accurate earthquake source parameters such as studies in seismic tomography, active tectonics and microseismicity (e.g., associated with hydraulic fracturing).
Multi-decadal time series of groundwater levels were compiled by the authors from records of observation wells initiated and maintained by government departments and research institutions in nine countries in sub-Saharan Africa. The pan-African collation of these hydrographs was initiated at the 41st Congress of the International Association of Hydrogeologists (IAH) in Marrakech (Morocco) on 14th September 2014. All records were subjected to a rigorous review by the authors during which the integrity, continuity, duration and interpretability of records were evaluated. This process included dedicated workshops in Benin, Tanzania, and Uganda, and records failing these tests were discarded from the analysis. Procedures included taking of the first time derivative to identify anomalous spikes in records commonly associated with errors of data-entry. Where multiple records in same geographic and climate zone were available (e.g. Benin, South Africa) we prioritized records remote from potential areas of intensive abstraction. Statistical clustering of records was also used in the Limpopo Basin of South Africa to identify the representativity of employed records at Modderfontein and Sterkloop.
Data has been recorded during triaxial rock deformation experiments where Lanhelin granite samples were subjected to dynamic and half-controlled shear failure. The data consists of mechanical data (load, displacement, confining pressure, strain gauge data), ultrasonic data (AE source locations and arrival times, sensor locations, arrival times of active acoustic surveys), and scanning electron microscope images of the samples after shear failure. Dataset contains all data necessary to evaluate the results presented in the paper entitled: 'Off-fault damage characterisation during and after experimental quasi-static and dynamic rupture in crystal rock from laboratory P-wave tomography and microstructures' by Aben, Brantut, and Mitchell, Journal of Geophysical Research: Solid Earth.
This poster on the UKCCSRC Call 2 project The Development and Demonstration of Best Practice Guidelines for the Safe Start-up Injection of CO2 into Depleted Gas Fields was presented at the CSLF Call project poster reception, London, 27.06.16. Grant number: UKCCSRC-C2-183. Highly-depleted gas fields represent prime potential targets for large-scale storage of captured CO2 emitted from industrial sources and fossil-fuel power plants. Given the potentially low reservoir pressures as well as the unique thermodynamic properties of CO2, especially in the presence of the various stream impurities, the injection process presents significant safety and operational challenges. In particular, the start-up injection leads to the following risks: • blockage due to hydrate and ice formation following the contact of the cold CO2 with the interstitial water around the wellbore; • thermal stress shocking of the wellbore casing steel, leading to its fracture and ultimately escape of CO2; • over-pressurisation accompanied by CO2 backflow into the injection system due to the violent evaporation of the superheated liquid CO2 upon entry into the wellbore.
This poster on the UKCCSRC Call 1 project Multiphase flow modelling for hazard assessment of dense phase CO2 pipelines containing impurities was presented at the CSLF Call project poster reception, London, 27.06.16. Grant number: UKCCSRC-C1-07. The aim of the project is to develop and validate experimentally a heterogeneous flow model for predicting the transient depressurisation and outflow following the puncture of dense-phase CO2 pipelines containing typical impurities. Given that CO2 is an asphyxiant at high concentrations, this information is pivotal to assessing all the hazard consequences associated with CO2 pipeline failure, including fracture propagation behaviour, atmospheric dispersion, emergency shutdown valve dynamics and emergency blowdown.
This presentation on the UKCCSRC (UK Carbon Capture and Storage Research Centre) Call 1 project, Multi-Phase Flow Modelling for Hazardous Assessment, was presented at the Cranfield Biannual, 22.04.15. Grant number: UKCCSRC-C1-07.
These data contain time series of stress, strain, confining pressure, pore pressure, pore volume, permeability and elastic wave velocities of samples of Purbeck Limestone deformed under hydrostatic and triaxial conditions at room temperature. All samples were saturated with decane as pore fluid.This dataset is used and fully described/interpreted in the paper: Brantut, N., M. Baker, L. N. Hansen and P. Baud, Microstructural control of physical properties during deformation of porous limestone, submitted to J. Geophys. Res.