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Reykjanes Peninsula: fires and faults as witnesses of a rifting episode

Nicolas Oestreicher1, 2, 3 , Joël Ruch1, Simon Bufféral4, Elisabetta Panza1, Xingjun Luo5, Yohann Chatelain1, Halldór Geirsson6, Þorsteinn Sæmundsson6, 7

  • Affiliations:  1Department of Earth Sciences, University of Geneva, Geneva, Switzerland; 2WSL Institute for Snow and Avalanche Research SLF, Davos, Switzerland; 3Climate Change, Extremes and Natural Hazards in Alpine Regions Research Centre CERC, Davos, Switzerland; 4Laboratoire de Géologie, École Normale Supérieure, PSL University, Paris, France; 5Lab of Volcano and Earthquake Research, School of Geosciences and Info-Physics, Central South University, 410083 Changsha, China; 6Department of Earth Sciences, University of Iceland, Reykjavik, Iceland; 7Faculty of Life and Environmental Sciences, University of Iceland, Reykjavik, Iceland 

  • Presentation type: Poster

  • Presentation time: Monday 16:30 - 18:30, Room Poster Hall

  • Poster Board Number: 164

  • Programme No: 3.1.56

  • Theme 3 > Session 1

Abstract

As the ongoing rifting episode began, the Reykjanes Peninsula in SW Iceland was deformed at the location of new dikes and eruption sites, affecting the entire peninsula. Our study examines surface deformation along an East-West transect of the peninsula, using a combination of InSAR (Interferometric Synthetic Aperture Radar) time-series, kinematic GNSS (Global Navigation Satellite System) data collected with a vehicle-mounted antenna, and high-resolution drone photogrammetry at selected locations of active faults. This integrative approach provides valuable insights for choosing appropriate surface deformation monitoring techniques during a volcano-tectonic unrest. Our analysis reveals how faults were reactivated and how new fractures formed between 2020 and 2024 by unveiling their strike, vertical offset, normal and shear displacement components. We detect fracture displacement at the centimetre scale and up to meters. The surface expression of fault displacement agrees with seismic moment tensors data at depth, and we highlight multiple NS-oriented faults with a right-lateral kinematic sense of motion. The tectonic stress release represents a critical part of the signal during the early phase of the rifting episode, coinciding with dike intrusions and facilitating magma transport to the surface. We demonstrate the benefits of combining different methods and resolutions to understand the deformation processes on the peninsula. These results contribute to refining monitoring strategies relevant to the broader scientific community.