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E446: How do earthquake cycles make geological structures? (Lead Supervisor: Alex Copley, Earth Sciences)

Supervisors: Alex Copley (Earth Sciences) and James Jackson (Department of Earth Sciences

Importance of the area of research:

One of the major unsolved problems in the Earth Sciences concerns understanding how repeated earthquake cycles produce topographic and geological structures (e.g. folds, faults, and mountains). Rapid technological and conceptual advances in the fields of seismology, satellite data, and numerical modelling, mean that we are now in a position to make significant new advances in this field. By making observations of deformation that span a wide range of timescales (seconds to millions of years) and length-scales (metres to hundreds of kilometres), and by modelling and synthesising these diverse observations, we can generate the first understanding of how repeated earthquake cycles create geological and topographic structures. One important implication of this work lies in the understanding and assessment of earthquake hazard. Additionally, the presence of many of the world's natural resources in fault-bounded mountain ranges and basins provides an economic relevance to this topic.

Project summary:

This project will make new fieldwork, remote sensing, geodetic, and seismological observations of earthquakes, the associated post- and inter-seismic motion, and the longer-term deformation preserved in geomorphology and geological structures. Comparing these datasets will reveal which aspects of earthquake cycle deformation are preserved in the geological record and as topographic structures. Modelling of these observations will pinpoint the material properties of the crust that control how and when geological structures are produced. This multidisciplinary approach provides greater insights than the use of one method alone. Important recent developments include new tools to estimate earthquake slip distributions, vast amounts of geodetic data being gathered by new satellites, and the ability to produce high-resolution elevation models from a new generation of optical satellite images.

What the student will do:

There are a number of possible target regions for the project, including Iran, Greece, India, and East Africa, and the student will work across at least two geographical areas. The student will begin by making field and remote-sensing observations of the geology and geomorphology in the target fault zones. They will then use InSAR and seismology to map the distribution of motion before, during, and after earthquakes. It will then be possible to compare the earthquake-cycle observations with the total deformation preserved in the geology and geomorphology, to address what motions, at what part of the earthquake cycle, produced the geological structures. The next step will be to use this new understanding, combined with dynamic models, to establish what material properties control the creation of geological structures, and so the geological evolution of the continents. By studying multiple regions, it will be possible to assess the importance of the parameters that vary between them (e.g. the thickness of the brittle upper crust, and the overall tectonic setting).

Please contact the lead supervisor directly for further information relating to what the successful applicant will be expected to do, training to be provided, and any specific educational background requirements.

References:

Copley, A., Mitra, S., Sloan, R.A., Gaonkar, S., and Reynolds, K., 2014, Active faulting in apparently stable peninsular India: rift inversion and a Holocene-age great earthquake on the Tapti Fault, Journal of Geophysical Research, doi:10.1002/2014JB011294

Copley, A., 2014, Postseismic afterslip 30 years after the 1978 Tabas-e-Golshan (Iran) earthquake: observations and implications for the geological evolution of thrust belts, Geophysical Journal International, 197, p 665-679, doi: 10.1093/gji/ggu023

Howell, A., Palamartchouk, K., Papanikolaou, X., Paradissis, D., Raptakis,C., Copley, A., England, P., and Jackson, J., 2017, The 2008 Methoni earthquake sequence: the relationship between the earthquake cycle on the subduction interface and coastal uplift in SW Greece, Geophysical Journal International, 208, p 1592-1610, doi: 10.1093/gji/ggw462

Follow this link to find out about applying for this project.

Other projects available from the Lead Supervisor can be viewed here.

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