Project #7

How tectonics affects seismic hazard parameters in complex continental settings

Main Supervisor: Ylona van Dinther (UU)
Co-Supervisor: Taras Gerya (ETH), Alice Gabriel (LMU)

Location: Universiteit Utrecht (Netherlands) –

Duration of the PhD: 4 years

The doctoral candidate will be enrolled in a PhD program at the Universiteit Utrecht

Objectives: Recent 2D tectonic earthquake sequence modelling of the Northern Apennines reveals that realistic tectonic loading and deep structures and rheology have a major impact on earthquake sequences in the upper continental crust. Specifically, the stress field and the type, distribution and rate of earthquakes in Northern Apennines are significantly affected by slab pull and lower crustal rheology, although these are not taken into account in earthquake sequence modelling or seismic hazard assessment. To understand these key features this doctoral candidate will first extend 2D visco-elasto-plastic, seismo-thermo-mechanical models, simulating earthquake sequences following millions of years tectonic, topography and fault evolution, down to milliseconds of earthquakes from strike slip to complex continental settings. To computationally efficiently simulate wave-mediated stress transfer in 3D, faults stress states will be coupled to the dynamic rupture model following recent achievements. Second, these new state-of-the-art models will be applied to spontaneously simulate and understand seismic hazard parameters (i.e., Mmax and b-value) as a function of important tectonic and rheological parameters (e.g., loading by mantle and lower crust, carbonate rheology, fluid flow). Third, a scenario in the Betics (Spain) will be constrained by observations from field studies, geodesy, seismology and fault geometries, and microphysical friction laws, using instantaneous modelling to assess its seismic hazard and compare those outcomes to more traditional PSHA approaches to converge towards a more physics-inspired PSHA methods.

Expected Results:

  1. 2D cross-scale / 3D coupled visco-elasto-plastic tectonic earthquake sequence models for complex continental settings;
  2. Improved understanding of how key tectonic and rheological parameters affect seismic hazard parameters in complex continental settings;
  3. Data-constrained physics-based scenario for seismic hazard assessment in the Betics.

Planned secondments: LMU (9 months, A. Gabriel, M18-22 & M34-37, Couple tectonic earthquake sequence models to dynamic rupture models in 3D complex continental settings for ground motion and hazard assessment); TNO (3 months, J.-D. van Wees, Loes Buijze, M27-29, model Mmax for induced seismicity in geothermal reservoirs using Linear Elastic Fracture Mechanics).