Geophysics Research Group University of Ulster, Coleraine

The Geophysics Research Group is offering Ph.D. projects in crustal fluids
and earthquake physics. Possible funding is available from a number of
sources including the Northern Ireland Department of Education and
Learning (DEL) and the University of Ulster; the latter through both Vice
Chancellor Research Scholarships and Teaching Assistantships. More
information about application procedures and funding is available at
http://www.ulst.ac.uk/research/rps/prospects/ while information about the
Group can be found at http://www.science.ulst.ac.uk/crg/geophys/index.html
or by contacting Dr. Sandy Steacy ([log in to unmask]). The deadline for
applications is 11 April 2003.

Briefly, students are being sought for:

1: Numerical Simulation of the dispersion of tracers in scale invariant,
fractured, porous materials.

Here the modified Lattice Boltzmann scheme will be used to solve the
advection-diffusion equation in a 3 dimensional complex geometry
consisting of a fractally-correlated, porous medium with a fractal
distribution of fractures. The project will use the parallel computing
facilities developed in the Geophysics Research group as part of an EPSRC
funded project on the scale invariance of earthquake populations. The
project will explore the influence of the statistics of the medium
geometry on the statistics of the plume dispersion. In particular, the
project will aim to elucidate the sensitivity of the plume dispersion in
the region of both the matrix and fracture percolation thesholds.

2: Physical modelling of the dispersion of tracers in scale invariant,
fractured, porous materials in the laboratory.

The Geophysics Research Group of the University of Ulster is currently
completing a NERC funded project on the measurement of fluid velocity
fields in complex geologically realistic media with scale invariant
geometries. These measurements are being used to validate numerical
predictions of fluid flow in these media. This project has involved the
construction of an experimental rig in which fluid moving in a 2D Hele-
Shaw cell can be examined. Here we propose that this apparatus should be
used to explore the movement of a tracer plume in such media. Specifically
it is proposed that the concentrations of tracers in the outflow should be
monitored in time at several places at the outflow from the cell so that
breakthrough curves might be measured. Video techniques will also be used
on visible tracers to monitor their progress throughout the model. In
addition, samples of fractured, porous rock will be prepared so that the
progress of a tracer plume might be monitored throughout the sample. All
results will be compared to theoretical and numerical predictions.

3:  Investigating the role of relaxation in realistically complex network
models of seismicity.

The aim of this project is to investigate both the extent to which
relaxation occurs and its effect on earthquake statistics in a 3-D network
model of distributed seismicity. Specific objectives include: 1) examining
the statistics of the seismicity resulting from models with varying
degrees of fault relaxation and fault geometry, 1) comparing predicted
seismicity statistics to observed seismicity in natural systems with
differing fault geometries, and 3) assessing the relative importance of
fault and system relaxation on patterns of seismicity.

4: Does a quantifiable seismic rate exist?

The aims of this project are to systematically investigate whether a
physically quantifiable seismic rate exists in reality or whether any
measure of rate simply depends on the size of the box (spatial and/or
temporal) in which the measurement is made. Specific objectives include:
1) Understanding the dependence of apparent seismic rate on the spatial
and temporal box size used in its measurement. 2) Examining the effects of
standard declustering algorithms on the computation of seismic rate. 3)
Elucidation of the physical mechanisms controlling seismic rate by
comparison with synthetic catalogs with known spatial and temporal
properties.