Utrecht University (UU) has great ambitions for its teaching quality and study success rates. This also applies to its clear research profiles which are centred around four themes: Dynamics of Youth, Institutions, Life Sciences and Sustainability. Utrecht University plays a prominent role in our society and contributes to finding the answers to topical and future societal issues.

The Department of Earth Sciences is now looking for a highly-motivated, high-potential applicant to fill a:

PhD position on constraining the maximum earthquake magnitude in Groningen using 3D multi-physics, data-driven modelling (4 years)

The seismic hazard due to induced seismicity in the Groningen gas field (the Netherlands) is largely determined by the maximum earthquake magnitude (Mmax) and the likelihood of its scenarios. Mmax is thus critical for political decision-making and hazard perception by society. Current Mmax estimates are determined using extrapolations from observed small earthquakes using event-based statistics and expert judgement. A physical basis is thus largely missing. Such a physical component is consistently challenging to include in any probabilistic seismic hazard assessments (PSHA) due to very high demands on computational costs. Particularly, the challenge in Groningen is to include the key physical processes on a particularly complex network of many, curved and intersecting faults. The PhD candidate will utilize recent advances in several computational communities to advance physics-based PSHA and provide physics-based estimates of Mmax in Groningen.

The PhD candidate will develop a 3D multi-physics, data-driven framework through linking two existing state-of-the-art methods and adding a third, novel semi-analytical model that will be further developed. First, probabilistic fault stresses will be provided by a semi-analytical reservoir simulator MACRIS1. These fault stresses will take into account improved geometries of the Groningen faults and the production history of the field. Subsequently, these pre-earthquake fault stresses, along with friction parameters derived in the laboratory in Utrecht on Groningen rocks, will be exported to 3D dynamic earthquake rupture simulations powered by High Performance Computing in SeisSol 2,3,4,5. Third, these dynamic simulations will serve to validate and extend a semi-analytical model based on linear elastic fracture mechanics (LEFM) theory for straight faults6 to complex fault geometries. This theory allows for a fast and probabilistic assessment of the likelihood of different Mmax scenarios across the field, while accounting for key uncertainties. The aim is that the results of this PhD project will be embedded in the Groningen risk assessment framework housed at the Geological Survey of the Netherlands (TNO). In the future, this new physical framework may also be of great value in determining the earthquake risk for induced and natural earthquakes in the Netherlands and worldwide. This could thus provide an important contribution in allowing for a safe and sustainable usage of the subsurface to facilitate our society's transition to sustainable energy. The project can therefore serve as a stepping stone for a career in fundamental earthquake physics or various societally and economically relevant industries.

The research team includes project leader Dr Ylona van Dinther (UU), Prof. Dr Jan-Diederik van Wees (TNO, UU), Dr Alice Gabriel (LMU Munich), Prof. Dr Jean-Paul Ampuero (GEOAZUR), Dr Thibault Candela (TNO), Dr Loes Buijze (TNO) and Prof. Dr Liviu Matenco (UU). Collaborators also appointed on the project include Dr Thomas Ulrich (LMU Munich) and Dr Huihui Weng (GEOAZUR). The research will mainly be performed at Utrecht University, but extended stays at the partner institutes in Germany and France are included in the project planning. Furthermore, this project is part of DeepNL, a long-term Dutch research programme into a better understanding of how the deep subsurface behaves under the influence of human interventions, e.g. in the gas reservoir in the province of Groningen (The Netherlands), and that aims to develop a knowledge base for geothermal energy extraction and underground CO2 and hydrogen storage.

Up to 10% of the candidate's time will be dedicated to assisting in the BSc and MSc teaching programmes of the Department of Earth Sciences. A personalised training programme will be set up, mutually agreed on recruitment, which will reflect the candidate's training needs and career objectives.

References:

  1. J.-D. van Wees et al. (2019). 3-D mechanical analysis of complex reservoirs: a novel mesh-free approach. Geophys. J. Int., 219(2), https://doi.org/10.1093/gji/ggz352
  2. C. Pelties et al. (2012). Three-dimensional dynamic rupture simulation with a high-order discontinuous Galerkin method on unstructured tetrahedral meshes. JGR: Solid Earth, 117, https://doi.org/10.1029/2011JB008857
  3. C. Uphoff et al. (2017). Extreme scale multi-physics simulations of the tsunamigenic 2004 Sumatra megathrust earthquake. SC'17 Proceedings, article 21, https://doi.org/10.1145/3126908.3126948
  4. T. Ulrich et al. (2019). Coupled, physics-based modeling reveals earthquake displacements are critical to the 2018 Palu, Sulawesi tsunami. Pure and Appl. Geophys., 176, https://doi.org/10.1007/s00024-019-02290-5
  5. I. van Zelst et al. (2019). Modeling megathrust earthquakes across scales: One-way coupling from geodynamics and seismic cycles to dynamic rupture. JGR: Solid Earth, 124, https://doi.org/10.1029/2019JB017539
  6. H. Weng & J.P. Ampuero (2019). The dynamics of elongated earthquake ruptures. JGR: Solid Earth, 124, https://doi.org/10.1029/2019JB017684

Qualifications:

The successful candidate should be ambitious and have a MSc (or equivalent) in Earth Sciences, Physics, or Engineering with demonstrable affinity with geophysical or sub-surface processes. Experience with one or more of the following topics would be an advantage: computational methods, analytical (theoretical) skills, (modelling of) earthquakes, faults, and reservoirs. A broad interest in earthquakes, and the willingness and capacity to interact with the team members, are essential. The candidate should be proficient in English and have excellent scientific writing and presenting skills. The candidate is an independent thinker, enthusiastic team player and has good communication skills.

Terms of employment:

You will be offered a full-time PhD position, initially for one year with extension up to four years in total upon a successful assessment in the first year, and with the specific intent that it results in a doctorate within this period. Employment conditions are based on the Collective Labour Agreement of the Dutch Universities. The gross monthly salary starts with € 2,395 in the first year and increases to € 3,061 in the fourth year of employment with a full-time appointment. The salary is supplemented by a holiday allowance of 8% per year and an end-of-year bonus of 8.3%. In addition, we offer a pension scheme, collective insurance schemes and flexible employment conditions.

About the organisation:

The Utrecht Faculty of Geosciences offers education and research concerning the geosphere, biosphere, atmosphere and hydrosphere. With a population of 3,400 students (BSc and MSc) and 720 staff, the Faculty is a strong and challenging organisation. The Faculty is organised in four Departments: Earth Sciences, Physical Geography, Sustainable Development, and Human Geography & Spatial Planning.

The Department of Earth Sciences conducts teaching and research across the full range of the solid Earth and environmental Earth sciences, with activities in almost all areas of geology, geochemistry, geophysics, biogeology and hydrogeology. The department hosts a highly international tenured staff of over 45 scientists and more than 110 PhD students and postdoctoral researchers. Our research programme spans four intertwined themes: Climate & Life, Earth interior, Earth materials, and Environmental Earth Sciences. We have access to or house a wide variety of world-class laboratories and infrastructures, which includes the Dutch National Super Computer hosted by SURFsara to be used in this project.

Additional information

For informal questions, please contact the project leader, Dr Ylona van Dinther, at y.vandinther@uu.nl.

How to apply:

To apply, please follow this link and the guidelines mentioned there. The application deadline is September 19th, 2021. Evaluations and interviews are planned soon thereafter, such that the position can start between October 15th 2021 and February 1st 2022.

Online screening may be part of the selection.

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posted: 28 July 2021     Please mention EARTHWORKS when responding to this advertisement.