Seismic twister: Crustal deformation along the Dinarides-Hellenides Transition in 4D

• Applicants: Professor Dr. Daniel Koehn; Dr. Sofia-Katerina Kufner
• Subject Area: Geophysics ; Geology
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 560302743

This project aims to answer the question how Earth’s crust reacts to the bending and rotation of a lithospheric slab at depth. We hypothesize that this bending and rotation causes a truly 3D upper crustal deformation zone, which consists of a mosaic of crustal blocks that experience distinct deformation histories. The Dinarides-Hellenides Transition Zone in Albania, one of the focus regions within DEFORM, is a prime natural laboratory to test this hypothesis. This region, where the Adriatic microplate converges with the western Balkans, experiences high seismic hazard compared to other parts of the plate boundary. The exact mechanisms and locations of crustal deformation remain debated. We here propose an analysis tool that can determine the deformation state across the entire crust—not just along active faults. Our interdisciplinary approach combines crustal anisotropy determination from shear wave splitting (SWS) and the method of stylolite stress inversion (SRIT). Upper crustal anisotropy may be due to stress-aligned microcracks, revealing the local stress field, but also may be structure related, e.g., close to fault systems, thus, carry information on their current or past activity. Stylolites, in turn, can be seen as stress-gauges, as they represent solution surfaces in rocks. Their analysis offers the possibility to decipher stress directions as well as the magnitude of the full stress tensor for different geological events, with the most recent commonly resampling the current stress field. Here, we will use data from a 400-station seismological network, which recorded 10,800 local earthquakes over nine months for SWS analysis and anisotropy inversion. To separate the superposition of different factors causing anisotropy, we will perform geological fieldwork and perform SRIT and ultimately combine these two datasets in a 3D Inversion. Our approach will produce a comprehensive model of the current crustal stress distribution as well as information on past deformation events. This will enhance our understanding of past and ongoing deformation and its relation to the seismic hazard potential. Bridging seismology and geology, our approach is novel and feasible as the seismological station spacing is on the same scale as geological structures. Within DEFORM, this project serves as a critical link between lithosphere-scale and surface-based studies and provides crucial data for modeling studies.

• DFG Programme: Priority Programmes
• Subproject of: SPP 2497: Plate Deformation and Geohazards: The Eastern Margin of the Adriatic Plate (DEFORM)
• International Connection: Albania
• Cooperation Partner: Professorin Dr. Ana Fociro
• Co-Investigator: Professor Dr. Andreas Rietbrock