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Hazard and risk assessment for fault movements on the Reykjanes peninsula, Iceland

Ásta Rut Hjartardóttir1, Michelle Parks1, Vincent Drouin1, Joaquin M. C. Belart2, Páll Einarsson3 and Bergrún Óladóttir1

  • Affiliations: 1Icelandic Meteorological Office, Reykjavík, Iceland; 2Natural Science Institute of Iceland, Garðabær, Iceland; 3Institute of Earth Sciences, University of Iceland, Reykjavík, Iceland 

  • Presentation type: Poster

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

  • Poster Board Number: 107

  • Programme No: 7.2.19

  • Theme 7 > Session 2

Abstract

Significant fault movements related to dike intrusions have been documented, e.g. in Iceland, Hawaii, and Ethiopia. The latest such events occurred on the Reykjanes peninsula, Iceland during an ongoing volcanic unrest. Nine dike intrusions formed from November 2023 to December 2024 of which seven led to fissure eruptions. The intrusions were in some cases accompanied by meter-scale movements along faults. Graben subsidence occurred in the town of Grindavík, where fault movements and subsidence caused significant damage to houses, roads and other infrastructure. An eruption in Fagradalsfjall in 2021 started a new eruptive period on the Reykjanes peninsula, after a hiatus of ~800 years. Previous research indicates that when one volcanic system on the peninsula starts erupting, several of the five others tend to follow within a timescale of tens to a few hundreds of years. Therefore, the Icelandic Meteorological Office is leading a volcanic hazard and risk assessment for the entire Reykjanes peninsula, of which fault movements are considered an important factor. The project is done in collaboration with municipalities, civil protection departments and companies/institutions responsible for maintaining important sources for inhabited areas on the peninsula, e.g. electricity, hot and cold water. Various critical infrastructure is located within the volcanic systems of the Reykjanes peninsula, such as high-temperature geothermal power plants and cold water supplies for larger towns, e.g. part of the capital area of Reykjavík. The hazard and risk assessment includes information on the location of faults and an attempt to estimate the likelihood that they will be reactivated.