EGU25-12897, updated on 15 Mar 2025
https://doi.org/10.5194/egusphere-egu25-12897
EGU General Assembly 2025
© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.
Validating the link between fault geometry and slip distribution
Tom Gabrieli1, Pierre Romanet2,3, Yuval Tal1, and Marco M. Schuderi2
Tom Gabrieli et al.
  • 1Ben-Gurion University of the Negev, Earth and Environmental Sciences, Shoham, Israel
  • 2Department of Earth Sciences, La Sapienza University of Rome, Piazzale Aldo Moro 5, 00185 Roma, Italy
  • 3Université Côte d’Azur, CNRS, IRD, Observatoire de la Côte d’Azur, Géoazur, Sophia-Antipolis, 06560 Valbonne, France

Fault geometry is increasingly regarded as a key parameter that affects all aspects of the earthquake cycle, yet the in-situ geometry of active faults remains poorly resolved, and they are often modeled as largely planar. On the other hand, recent advances in sensing and computational abilities enable measuring the co-seismic slip of large earthquakes in high resolution, both on the surface and at seismogenic depths. Previous analytical and numerical studies showed that the slip distribution of an earthquake is mechanically linked to the fault geometry through its curvature, though this link has not yet been verified. Here we show experimental verification of this link, by measuring at high precision the shear slip profiles along non-planar interfaces in laboratory earthquakes. We trigger dynamic shear ruptures that propagate along the interface between two loaded and matching PMMA plates and, using image correlation of ultrahigh-speed photography, resolve the propagating ruptures and the resulting displacements. The plates are pre-cut along a desired geometry, and we compare the slip calculated from the geometry and the experimental shear slip at each pixel along the interface. We show that, as predicted analytically, fault curvature is correlated to slip gradient when the plates are in contact and anti-correlated when there is opening. These relationships are clearly visible in our results at all measured scales regardless of the rupture complexity. Our results suggest that variations of the co-seismic slip along a fault can be highly indicative of the in-situ fault geometry and, alternatively, that slip distribution may be predicted along a fault with known geometry.

How to cite: Gabrieli, T., Romanet, P., Tal, Y., and Schuderi, M. M.: Validating the link between fault geometry and slip distribution, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-12897, https://doi.org/10.5194/egusphere-egu25-12897, 2025.