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Rapid detection of faults and fractures using drone magnetometry: Insights from the Grindavík hazard zone, Reykjanes Peninsula, Iceland

Elisa Johanna Piispa 1, Catherine Rachel Gallagher1,2, Gunnlaugur Magnús Einarsson3, Sindri Bernholt1, Katrín Ásta Karlsdóttir3, Ögmundur Erlendsson3, Irma Gná Jóngeirsdóttir3, Alexandra Kristín Hafsteinsdóttir3, Birgir Vilhelm Óskarsson4, Rosemary Philippa Cole1, Hannah Iona Reynolds1, and Robert Alexander Askew1,4

  • Affiliations: 1University of Iceland, Reykjavik, Iceland; 2HS Orka, Kópavogur, Iceland; 3Iceland GeoSurvey (ÍSOR), Kópavogur, Iceland; 4Natural Science Institute of Iceland, Garðabær, Iceland  

  • Presentation type: Poster

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

  • Poster Board Number: 63

  • Programme No: 6.3.22

  • Theme 6 > Session 3

Abstract

The renewed tectonic and volcanic activity in Reykjanes Peninsula also resulted in significant faulting, fracturing, and graben formation in the town of Grindavík in November 2023 and January 2024. This posed risk to infrastructure and public safety, particularly through the formation of sinkholes, subsidence, and surface instability. Effective mitigation of this activity required rapid and accurate mapping of the structures in the subsurface.  Drone-based magnetometry provides a novel possibility for detecting and characterizing subsurface faults, sinkholes and fractures. By measuring magnetic anomalies caused by contrasts between nonmagnetic features, such as sinkholes and fractures, and highly magnetic basaltic lavas, this technique can efficiently map hazardous areas, even in challenging terrain. This study highlights the application of drone magnetometry in the Grindavík hazard zone. By integrating magnetometry with complementary datasets such as InSAR and DEMs, we provided insights into the fault and fracture systems associated with the graben formation. The results demonstrate the method's usefulness in rapid-response scenarios, which are essential for informed hazard assessments, decision making, and risk mitigation in tectonically active regions.