Strike-Slip Fault-Generated Paleotsunamis in Lake Iznik (NW Türkiye): Numerical Modeling Corroborated by Coastal Deposits

Abstract

Strike-slip faults in lacustrine environments present overlooked tsunamigenic potential. For the first time, we have reconstructed paleotsunamis triggered by strike-slip faulting with a dip-slip component that ruptured the lake floor. This study focuses on Lake Iznik (Türkiye), located along the middle strand of the North Anatolian Fault (MNAF). We modeled tsunami generation, propagation, and inundation for the 121 CE (Mw ∼7.3) and 1065 CE (Mw ∼6.9) earthquakes using a coupled coseismic dislocation and hydrodynamic model. Simulated run-ups and inundation distances are validated against coastal tsunami deposits. Our results show maximum run-ups of ∼3 m for the 121 CE event and ∼1 m for the 1065 CE event, highlighting the tsunami hazard to the lakeshore. We also demonstrate that the tsunami generated during the 1065 CE event lacked sufficient wave height (<0.5 m) to damage the newly discovered submerged Byzantine basilica. These findings emphasize the need to integrate tsunami risk into seismic hazard assessments for lacustrine strike-slip fault zones.

Keywords

Bibliographic record

BibTeX Citation

@article{Zafar2025strikeslipfaultgenerated,
  author = {Zafar, M. and Dutykh, D. and Paris, R. and Gastineau, R. and De Sigoyer, J. and Duarte, E. and Ünsal, N. and Harrichhausen, N. and Flavard, S. and Sahin, M. and Sabatier, P.},
  title = {Strike-Slip Fault-Generated Paleotsunamis in Lake Iznik (NW Türkiye): Numerical Modeling Corroborated by Coastal Deposits},
  journal = {Geophys. Res. Lett.},
  year = {2025},
  volume = {52},
  number = {18},
  pages = {e2025GL117422},
  doi = {10.1029/2025GL117422},
  abstract = {Strike-slip faults in lacustrine environments present overlooked tsunamigenic potential. For the first time, we have reconstructed paleotsunamis triggered by strike-slip faulting with a dip-slip component that ruptured the lake floor. This study focuses on Lake Iznik (Türkiye), located along the middle strand of the North Anatolian Fault (MNAF). We modeled tsunami generation, propagation, and inundation for the 121 CE (Mw ∼7.3) and 1065 CE (Mw ∼6.9) earthquakes using a coupled coseismic dislocation and hydrodynamic model. Simulated run-ups and inundation distances are validated against coastal tsunami deposits. Our results show maximum run-ups of ∼3 m for the 121 CE event and ∼1 m for the 1065 CE event, highlighting the tsunami hazard to the lakeshore. We also demonstrate that the tsunami generated during the 1065 CE event lacked sufficient wave height (<0.5 m) to damage the newly discovered submerged Byzantine basilica. These findings emphasize the need to integrate tsunami risk into seismic hazard assessments for lacustrine strike-slip fault zones.},
  keywords = {paleotsunami, strike-slip fault, Lake Iznik, North Anatolian Fault, tsunami modeling, coastal deposits, lacustrine tsunami, seismic hazard},
  publisher = {American Geophysical Union (AGU)},
  issn = {0094-8276}
}