“Monitoring the Interior of Solids and Fluids using Multiply-Scattered Waves”Supervisors: Prof. Andrew Curtis, Dr. Giovanni Meles (The University of Edinburgh, UK)
Fully Funded Ph.D. Project for National or International Students
We often wish to monitor changes in the interior of solids or fluids from measurements on their surfaces. In the Earth’s interior, earthquakes move bodies of rock relative to one-another changing fracture and fault distributions and stresses; magma movements and volcanic eruptions change subsurface temperatures, pressures and fluid distributions; the injection of fluids into the subsurface to extract geothermal energy or to store waste, natural gas or CO2 in subsurface reservoirs, or the extraction of either fluids such as water or hydrocarbons, or solids such as ores or minerals, directly changes the distribution of subsurface fluids, stress fields, chemistry and heat.
These effects are usually monitored using Geophysical measurements made on the Earth’s surface. Many of these measurements involve injecting seismic or electromagnetic waves into the subsurface, and recording the waves that emerge again at the surface after being scattered in complex ways by variations in fluid or rock properties in the subsurface. By repeating the measurements at different times, changes in the scattered wavefields between the different measurements allow us to detect changes in the subsurface properties.
This project aims to improve the way that we interpret such information from recordings of complex wavefields. We will develop methods to image and monitor changes in the Earth’s subsurface (described above), or in the interior of other solid or fluid bodies (e.g., fish moving in oceans, flaws developing in industrial components, masonry integrity in buildings, or changes inside humans in medical imaging).
The recorded wavefields usually have an easily understood component comprising waves that have been reflected, refracted, diffracted or scattered only once within the medium before returning to the surface, followed by a complex ‘coda’ comprising many overlapping waves that were scattered multiple times as they travelled through the medium. While the singly-scattered component is relatively easy to interpret, statistical properties of the coda have been shown to have far greater sensitivity to changes occurring inside the medium. Ideally we would be able to use both parts of the wavefield to image and monitor such changes.
Recently scientists in Edinburgh have discovered the first direct link between the first few diffractions of waves returning from the interior of the body, and the waves arriving in the coda. For the first time this may allow both the singly- and multiply-scattered waves to be understood and interpreted within the same theoretical framework. You will explore these initial, exciting results and develop them further, investigating how we can use them for practical monitoring of the interior of solid and fluid bodies.
This PhD has a generous EU-level salary, funds for international research visits & conferences, and is part of a European network of 15 PhD students working on related topics and with who you will regularly interact.
You will be trained in all relevant specialities, and will carry out your research by developing further the mathematical equations describing relevant wave theory, exploring the physics of waves and their interactions with solids and fluids, programming and using high performance computers, and through laboratory or field experimentation. The University of Edinburgh has equipment to perform geophysical field tests, access to large industrial data sets of subsurface seismic surveys and global seismological databases, very large computational power for data analysis, courses in necessary programming skills, and experts in the mathematics and physics of waves. This project is in collaboration with the Université Joseph Fourier in Grenoble, France, to which you would make extended visits: that university has laboratories to explore acoustic, elastic and electromagnetic scattered wave phenomena, and expertise in both theoretical and experimental physics.
Apply on-line at: http://www.ed.ac.uk/schools-departments/geosciences/postgraduate/phd/programmes-supervisors/physical-sciences/phd-projects?DisciplineID=3#projectlist
For more information contact: Prof. Andrew Curtis (Andrew.Curtis@ed.ac.uk)
How good is research at University of Edinburgh in Earth Systems and Environmental Sciences?
FTE Category A staff submitted: 104.98
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