Crustal stress state from combined anisotropic seismic imaging and geomechanical modeling

The Earth’s crust is a mechanically heterogeneous system in which stress, fractures, and geofluids are tightly coupled and jointly control deformation. Quantifying the present-day crustal stress state remains challenging, as it is commonly inferred from indirect and spatially sparse observations and often relies on simplifying assumptions in seismic imaging and mechanical models.

We present a methodological framework that combines probabilisitic anisotropic seismic imaging with geomechanical modeling to constrain the crustal stress state in a physically consistent manner. Seismic anisotropy in the upper crust, expressed through directional variations in elastic properties, is used as a proxy for fracture orientation, fracture density, and fluid-induced compliance, which are intrinsically linked to the ambient stress field. Incorporating anisotropic parameters into seismic imaging reduces inversion artifacts and enables a more robust characterization of stress-aligned fracture networks.

These seismic constraints are integrated into geomechanical models that simulate the stress field under realistic boundary conditions and rheological properties, and calibrated by direct comparison between observed stress indicators (e.g. seismic T-axes, surface faulting patterns, fast shear wave polarisations), anisotropy patterns and model-predicted stress orientations. This combined approach improves stress-state quantification by leveraging seismically-inferred 3D fracture patterns while also providing a framework to assess uncertainties arising from seismic imaging assumptions and mechanical parameter choices.

The proposed methodology is broadly applicable to tectonic and volcanic settings, as well as geothermal and oil fields, and offers a transferable strategy for improving stress-state estimates in regions where direct measurements are limited.