How do complex fault geometries influence earthquake cycle deformation?

The School of Earth, Environment, and Sustainability at the University of Leeds invites applications from prospective postgraduate researchers who wish to commence study for a PhD in the academic year 2026/27. This opportunity is open to UK applicants and covers UK fees plus a maintenance allowance matching current UKRI rates (£21,805 in 2026/27). <br /> <br /> This exciting project aims to understand how complicated fault geometries influence earthquake style and recurrence. You will combine field work, lab analyses, and seismology to investigate fault slip patterns on multiple scales in time and space. <br /> <br /> Heterogeneities in fault system geometries may strongly influence earthquake nucleation and recurrence (Cowie et al., 2012; Dieterich and Richards-Dinger, 2010; Walters et al., 2018). In particular, normal faults display complex geometries due to the mechanisms by which they evolve and grow, and the relationship between repeated faulting and the growth of topography in the footwall (Ciftci and Bozkurt, 2007; DuRoss et al., 2019). Fault geometry complexities such as segmentation, relays, and branches can act as persistent barriers to rupture, but might also invoke heterogeneities in stress and strength that could influence the size and frequency distributions of earthquake rupture (Goebel et al., 2015). In this project you will characterise fault behaviour across different scales in time and space to better quantify how complex geometries may influence patterns of earthquake recurrence.

<p>Faults in the V-shaped Dinar-Baklan basin in western Turkey intersect at a perpendicular angle at the fault terminations. There are three main faults accommodating extension across the region, including the Dinar fault that ruptured in an Ms 6.1 eathquake on the 1 October, 1995 (Altunel et al., 1999; Eyidogan and Barka, 1996). Localities have been identified to collect samples to measure the Quaternary fault slip rate, and how it varies through time, on each fault using cosmogenic isotope analyses. Cosmogenic isotopes are a Quaternary dating technique that quantifies how earthquakes have displaced the ground surface over multiple earthquake cycles and thousands of years (Goodall et al., 2021; Schlagenhauf et al., 2010). Results from these analyses will illuminate how the fault slip rate has varied over time, and whether these three faults have similar patterns of displacement. </p> <p>Deformation across western Turkey is accommodated on a complicated network of large normal faults with variable orientations (Bozkurt, 2003; Bozkurt and Sozbilir, 2004; Uzel, 2016). Rapid extension is distributed across the large network of normal faults, but exactly how each fault contributes, and whether there are major unknown faults that also may be important, is still unknown (e.g. Nissen et al., 2022). This project will aim to determine the precise geometry of the Dinar-Baklan basin faults at depth using geological mapping, cross sections, and seismology. The surface expression of the faults will also be mapped in detail using Terrestrial Laser Scanning (TLS), UAV – RS, and field mapping to characterise which aspect of geometry are likely to be important at depth. Further seismological observations covering western Turkey will aim to quantify characteristics of faulting (b-values, empirical density distributions), which will help to understand how regional deformation varies in space and time. </p> <p>Ultimately, regional earthquake statistics can be used to conduct physics-based earthquake models that can be incorporated into statistically based earthquake hazard models (Shaw et al., 2018). This project aims to gain a better understanding of how complex faulting may influence the pattern of earthquakes across western Turkey, and has the potential for significant scientific and human impact. </p> <p paraeid="{c0b39875-fa37-4f62-b141-c0441f72ca39}{174}" paraid="1738547839"><strong>Objectives </strong></p> <ol role="list" start="1"> <li aria-setsize="-1" data-aria-level="1" data-aria-posinset="1" data-font="" data-leveltext="%1." data-list-defn-props="{"335552541":0,"335559685":720,"335559991":360,"469769242":[65533,0],"469777803":"left","469777804":"%1.","469777815":"hybridMultilevel"}" data-listid="28" role="listitem"> <p paraeid="{c0b39875-fa37-4f62-b141-c0441f72ca39}{180}" paraid="89671461">Determine detailed fault slip rates on three faults in western Turkey using cosmogenic isotope analyses on bedrock fault scarps (Cowie et al., 2017; Goodall et al., 2021). You will conduct fieldwork to collect samples from sites identified previously and conduct detailed field-based surveys of the sites (e.g. using Terrestrial Laser Scanning, TL; Bubeck et al., 2015). You will process the samples in the lab, analyse the results, and model the data using Bayesian MCMC methods to determine time-variable fault slip rates for each fault. </p> </li> </ol> <ol role="list" start="2"> <li aria-setsize="-1" data-aria-level="1" data-aria-posinset="2" data-font="" data-leveltext="%1." data-list-defn-props="{"335552541":0,"335559685":720,"335559991":360,"469769242":[65533,0],"469777803":"left","469777804":"%1.","469777815":"hybridMultilevel"}" data-listid="28" role="listitem"> <p paraeid="{c0b39875-fa37-4f62-b141-c0441f72ca39}{205}" paraid="648938553">Investigate the structure of the Dinar – Baklan basin at depth using field based geological mapping, cross sections, and available seismological data. Combined with fault slip rate data, you will aim to better understand how cross-cutting basins evolve and interact at depth. You will investigate whether there are major barriers to rupture of these complex faults, and there is scope to conduct rupture modelling to determine how rupture scenarios might evolve over multiple earthquake cycles on intersecting faults.  </p> </li> </ol> <ol role="list" start="3"> <li aria-setsize="-1" data-aria-level="1" data-aria-posinset="3" data-font="" data-leveltext="%1." data-list-defn-props="{"335552541":0,"335559685":720,"335559991":360,"469769242":[65533,0],"469777803":"left","469777804":"%1.","469777815":"hybridMultilevel"}" data-listid="28" role="listitem"> <p paraeid="{c0b39875-fa37-4f62-b141-c0441f72ca39}{211}" paraid="2095372254">Investigate the seismological characteristics of normal faults across western Turkey to quantify earthquake statistics for the complex network of faults that span this region (Dieterich and Richards-Dinger, 2010). Depending on your interests, you may further investigate fault properties by investigating paleostress indicators and fault surface roughness. </p> </li> </ol> <p paraeid="{c0b39875-fa37-4f62-b141-c0441f72ca39}{229}" paraid="1916429745"><strong>Fit to NERC science </strong></p> <p paraeid="{c0b39875-fa37-4f62-b141-c0441f72ca39}{235}" paraid="1163671003">This project directly addresses NERCs aim to tackle challenges faced by the world in the fields of hazards and solid earth science. NERC has a priority to increase the understanding of environmental hazards to manage vulnerability, risk, response and recovery – and this project aims to better understand the fundamental processes that affect how and when earthquakes occur. We will be working in western Turkey, which hosts many earthquakes and where there are significant populations exposed directly to this hazard. Our research will not only improve our understanding of fundamental processes of earthquakes in general, but also specifically on the targeted faults in western Turkey. </p> <p paraeid="{c0b39875-fa37-4f62-b141-c0441f72ca39}{241}" paraid="963311148"><strong>Logistics </strong></p> <p paraeid="{c0b39875-fa37-4f62-b141-c0441f72ca39}{251}" paraid="1052954007">You will be based in the <a href="https://environment.leeds.ac.uk/see" rel="noreferrer noopener" target="_blank">School of Earth, Environment, and Sustainability</a> at the University of Leeds. You will work alongside scientists and students in the <a href="https://environment.leeds.ac.uk/institute-geophysics-tectonics" rel="noreferrer noopener" target="_blank">Institute of Geophysics and Tectonics</a>. You will also be part of the UK-wide network <a href="https://comet.nerc.ac.uk/" rel="noreferrer noopener" target="_blank">COMET</a>, the Centre for the observation and modelling of earthquakes, volcanoes, and tectonics.  </p> <p><strong>Key References </strong></p> <p>Altunel, E., Barka, A., and Akyuz, S., 1999, Palaeoseismicity of the Dinar fault, SW Turkey: Terra Nova, v. 11, p. 297-302. </p> <p>Bozkurt, E., 2003, Origin of NE-trending basins in western Turkey: Geodinamica Acta, v. 16, p. 61-81. </p> <p>Bozkurt, E., and Sozbilir, H., 2004, Tectonic evolution of the Gediz Graben: field evidence for an episodic, two-stage extension in western Turkey: Geological Magazine, v. 141, no. 1, p. 63-79. </p> <p>Bubeck, A., Wilkinson, M., Roberts, G. P., Cowie, P. A., McCaffrey, K. J. W., Phillips, R. J., and Sammonds, P., 2015, The tectonic geomorphology of bedrock scarps on active normal faults in the Italian Apennines mapped using combined ground penetrating radar and terrestrial laser scanning: Geomorphology, v. 237, p. 38-51. </p> <p>Ciftci, N. B., and Bozkurt, E., 2007, Anomalous stress field and active breaching at relay ramps: A field example from Gediz Graben, SW Turkey: Geological Magazine, v. 144, p. 687-699. </p> <p>Cowie, P. A., Phillips, R. J., Roberts, G. P., McCaffrey, K. J. W., Zijerveld, L. J. J., Gregory, L. C., Faure Walker, J., Wedmore, L. N. J., Dunai, T. J., Binnie, S. A., Freeman, S. P. H. T., Wilcken, K., Shanks, R. P., Huismans, R. S., Papanikolaou, I., Michetti, A. M., and Wilkinson, M., 2017, Orogen-scale uplift in the central Italian Apennines drives episodic behaviour of earthquake faults: Scientific Reports, v. 7:44858. </p> <p>Cowie, P. A., Roberts, G. P., Bull, J. M., and Visini, F., 2012, Relationships between fault geometry, slip rate variability and earthquake recurrence in extensional settings: Geophysical Journal International. </p> <p>Dieterich, J. H., and Richards-Dinger, K. B., 2010, Earthquake Reccurence in Simulated Fault Systems: Pure Appl. Geophys., v. 167, p. 1087–1104. </p> <p>DuRoss, C. B., Bunds, M. P., Gold, R. D., Briggs, R. W., Reitman, N. G., Personius, S. F., and Toke, N. A., 2019, Variable normal-fault rupture behavior, northern Lost River fault zone, Idaho, USA: Geosphere, v. 15, no. 6, p. 1869-1892. </p> <p>Eyidogan, H., and Barka, A., 1996, The 1 October 1995 Dinar earthquake, SW Turkey: Terra Nova, v. 8, p. 479-485. </p> <p>Goebel, T. H. W., Sammis, C. G., Becker, T. W., Dresen, G., and Schorlemmer, D., 2015, A comparison of seismicity characteristics and fault structure between stick-slip experiments and nature: Pure Appl. Geophys., v. 172, p. 2247-2264. </p> <p>Goodall, H. J., Gregory, L. C., Wedmore, L. N. J., McCaffrey, K. J. W., Amey, R. M. J., Roberts, G. P., Shanks, R. P., Phillips, R. J., and Hooper, A., 2021, Determining histories of slip on normal faults with bedrock scarps using cosmogenic nuclide exposure data: Tectonics, v. 40, p. e2020TC006457. </p> <p>Nissen, E., Cambaz, M. D., Gaudreau, E., Howell, A., Karasozen, E., and Savidge, E., 2022, A reappraisal of active tectonics along the Fethiye-Burdur trend, southwestern Turkey: Geophysical Journal International, v. 230, p. 1030-1051. </p> <p>Schlagenhauf, A., Gaudemer, Y., Benedetti, L., Manighetti, I., Palumbo, L., Schimmelpfennig, I., Finkel, R., and Pou, K., 2010, Using in situ Chlorine-36 cosmonuclide to recover past earthquake histories on limestone normal fault scarps: a reappraisal of methodology and interpretations: Geophysical Journal International. </p> <p>Shaw, B. E., Milner, K. R., Field, E. H., Richards-Dinger, K. B., Gilchrist, J. J., Dieterich, J. H., and Jordan, T. H., 2018, A physics-based earthquake simulator replicates seismic hazard statistics across California: Science Advances, v. 4, p. eaau0688. </p> <p>Uzel, B., 2016, Field evidence for normal fault linkage and relay ramp evolution: the Kirkagac fault zone, western Anatolia (Turkey): Geodinamica Acta, v. 28, no. 4, p. 311-327. </p> <p>Walters, R. J., Gregory, L. C., Wedmore, L. N. J., Craig, T. J., McCaffrey, K. J. W., Wilkinson, M., Chen, J., Li, Z., Elliott, J. R., Goodall, H., Iezzi, F., Livio, F., Michetti, A. M., Roberts, G., and Vittori, E., 2018, Dual control of fault intersections on stop-start rupture in the 2016 Central Italy seismic sequence: Earth and Planetary Science Letters, v. 500, p. 1-14. </p> <p> </p> <p><strong>Selection process</strong></p> <ul> <li>All applications will be considered after the deadline. </li> <li>Awards are based on academic merit and no other factors such as financial hardship are taken into account. </li> <li>Applicants will be e-mailed within 4 weeks of the deadline to confirm the outcome. </li> </ul> <p> </p> <p><strong>Other Conditions </strong></p> <ul> <li>Awards must be taken up by 1 October 2026 </li> <li>Candidates who have previously been awarded a PhD or are currently registered on a PhD are excluded from applying. Those who were previously studying for a PhD but did not complete may be considered. </li> <li>Applicants must live within a reasonable distance of the University of Leeds whilst in receipt of this Studentship. </li> <li>Please be aware that any expenses related to the relocation of international students to the UK (visa, insurance, NHS fees, flights, etc) would be their responsibility and is not covered by this award. </li> </ul>

<p>Formal applications for research degree study should be made online through the <a href="https://www.leeds.ac.uk/research-applying/doc/applying-research-degrees">University's website</a>. <strong>Please state clearly</strong> in the research information section that the research degree <strong>you wish to be considered for is <em>How do complex fault geometries influence earthquake cycle deformation?</em></strong> as well as <a href="https://environment.leeds.ac.uk/see/staff/1296/dr-laura-gregory">Dr. Laura Gregory</a> as your proposed supervisor.</p> <p>You will be required to provide a CV and a brief personal statement which outlines your interest in the project you are applying for, why you have chosen it and how your skills map onto the requirments of the project.</p> <p>If English is not your first language, you must provide evidence that you meet the University's minimum English language requirements (below).</p> <p><em>As an international research-intensive university, we welcome students from all walks of life and from across the world. We foster an inclusive environment where all can flourish and prosper, and we are proud of our strong commitment to student education. Across all Faculties we are dedicated to diversifying our community and we welcome the unique contributions that individuals can bring, and particularly encourage applications from, but not limited to Black, Asian, people who belong to a minority ethnic community, people who identify as LGBT+ and people with disabilities. Applicants will always be selected based on merit and ability.</em></p>

Applicants to research degree programmes should normally have at least a first class or an upper second class British Bachelors Honours degree (or equivalent) in an appropriate discipline. The criteria for entry for some research degrees may be higher, for example, several faculties, also require a Masters degree. Applicants are advised to check with the relevant School prior to making an application. Applicants who are uncertain about the requirements for a particular research degree are advised to contact the School or Graduate School prior to making an application.

The minimum English language entry requirement for research postgraduate research study is an IELTS of 6.0 overall with at least 5.5 in each component (reading, writing, listening and speaking) or equivalent. The test must be dated within two years of the start date of the course in order to be valid. Some schools and faculties have a higher requirement.

<p>We are offering a fully funded scholarship to study the project ‘How do complex fault geometries influence earthquake cycle deformation?’, at the school of Earth, Environment, and Sustainability, University of Leeds for one UK status candidate. The funding covers UK tuition fees as well as a UKRI matched maintenance stipend (currently £21,805 in 2026/27) per year, for three and a half years, subject to satisfactory progress.</p> <p>Applicants must be eligible to pay fees at the Home (UK) rate.</p> <p>If you are unsure whether you are eligible for UK fees/funding, please see our <a href="https://www.leeds.ac.uk/undergraduate-fees/doc/fee-assessment">fee assessment page.</a></p>

<p>For further information please contact lead supervisor Laura Gregory: <a href="mailto:L.C.Gregory@leeds.ac.uk">L.C.Gregory@leeds.ac.uk</a></p> <p>For admissions guidance please contact the Faculty of Environment PRG Admissions Team: ENV-PGR@leeds.ac.uk</p> <p> </p>