0636838 - GFÚ 2026 RIV US eng J - Journal Article
Glastonbury-Southern, E. - Winder, T. - Rawlinson, N. - White, R. S. - Greenfield, T. - Bacon, C. A. - Ágústsdóttir, T. - Brandsdóttir, B. - Gudnason, E. Á. - Hersir, G. P. - Fischer, T. J. - Doubravová, Jana - Hrubcová, Pavla - Eibl, E.P.S.
Pre-existing structures control the orientation of strike-slip faulting during the 2021 dike intrusion at Fagradalsfjall, Iceland.
Journal of Geophysical Research-Solid Earth. Roč. 130, č. 6 (2025), č. článku e2024JB030162. ISSN 2169-9313. E-ISSN 2169-9356
R&D Projects: GA TA ČR(CZ) TO01000198; GA ČR(CZ) GX25-16408X
Institutional support: RVO:67985530
Keywords : reykjanes peninsula * induced earthquakes * plate boundary * volcano * seismicity * rift * deflation * dike intrusion * microseismicity * fault plane solutions
OECD category: Volcanology
Impact factor: 3.9, year: 2023 ; AIS: 1.536, rok: 2023
Method of publishing: Open access
Result website:
https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2024JB030162DOI: https://doi.org/10.1029/2024JB030162

The 2021 Fagradalsfjall inflation and dike intrusion marked the initiation of a new era of volcanism on Iceland's Reykjanes Peninsula. We present a large automatic catalog consisting of more than 80,000 earthquake hypocenters spanning the full period of the dike intrusion, which were derived from seismic data recorded by a dense network of seismometers. The 9-10 km long dike exhibits a two-segment geometry of similar lengths. Linear regression on a relatively relocated subset of over 12,000 earthquakes revealed a strike of 029 degrees with a standard deviation of 2 degrees in the southern segment, and 046 degrees with a standard deviation of 1 degrees in the northern segment of the dike. A total of 97 detailed fault plane solutions from selected subsets of events provide new insight into the controls on faulting, showing almost exclusively right-lateral strike-slip/oblique-slip faulting associated with the dike intrusion, and a lack of left-lateral strike-slip fault motion. The alignment of fault planes is consistent with the orientation of pre-existing structures, within uncertainty estimates. In light of these observations, we conclude that the dominant controlling factor on the orientation of dike-related faulting is the extensive network of pre-existing structures formed by the active transtensional plate boundary along the Reykjanes Peninsula.
Permanent Link: https://hdl.handle.net/11104/0367910