@article{ZieglerRajabiHeidbachetal.2016,
  author    = {Ziegler, Moritz O. and Rajabi, Mojtaba and Heidbach, Oliver and Hersir, Gylfi Pall and Agustsson, Kristjan and Arnadottir, Sigurveig and Zang, Arno},
  title     = {The stress pattern of Iceland},
  series = {Tectonophysics : international journal of geotectonics and the geology and physics of the interior of the earth},
  volume    = {674},
  journal   = {Tectonophysics : international journal of geotectonics and the geology and physics of the interior of the earth},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0040-1951},
  doi       = {10.1016/j.tecto.2016.02.008},
  pages     = {101 -- 113},
  year      = {2016},
  abstract  = {Iceland is located on the Mid-Atlantic Ridge which is the plate boundary between the Eurasian and the North American plates. It is one of the few places on earth where an active spreading centre is located onshore but the stress pattern has not been extensively investigated so far. In this paper we present a comprehensive compilation of the orientation of maximum horizontal stress (S-Hmax). In particular we interpret borehole breakouts and drilling induced fractures from borehole image logs in 57 geothermal wells onshore Iceland. The borehole results are combined with other stress indicators including earthquake focal mechanism solutions, geological information and overcoring measurements resulting in a dataset with 495 data records for the S-Hmax orientation. The reliability of each indicator is assessed according to the quality criteria of the World Stress Map project The majority of S-Hmax orientation data records in Iceland is derived from earthquake focal mechanism solutions (35\%) and geological fault slip inversions (26\%). 20\% of the data are borehole related stress indicators. In addition minor shares of S-Hmax orientations are compiled, amongst others, from focal mechanism inversions and the alignment of fissure eruptions. The results show that the S-Hmax orientations derived from different depths and stress indicators are consistent with each other. The resulting pattern of the present-day stress in Iceland has four distinct subsets of S-Hmax orientations. The S-Hmax orientation is parallel to the rift axes in the vicinity of the active spreading regions. It changes from NE-SW in the South to approximately N-S in central Iceland and NNW-SSE in the North. In the Westfjords which is located far away from the ridge the regional S-Hmax rotates and is parallel to the plate motion. (C) 2016 Elsevier B.V. All rights reserved.},
  language  = {en}
}
@article{FlovenzWangHersiretal.2022,
  author    = {Fl{\´o}venz, {\´O}lafur G. and Wang, Rongjiang and Hersir, Gylfi P{\´a}ll and Dahm, Torsten and Hainzl, Sebastian and Vassileva, Magdalena and Drouin, Vincent and Heimann, Sebastian and Isken, Marius Paul and Gudnason, Egill {\´A}. and {\´A}g{\´u}stsson, Kristj{\´a}n and {\´A}g{\´u}stsd{\´o}ttir, Thorbj{\"o}rg and Hor{\´a}lek, Josef and Motagh, Mahdi and Walter, Thomas R. and Rivalta, Eleonora and Jousset, Philippe and Krawczyk, Charlotte M. and Milkereit, Claus},
  title     = {Cyclical geothermal unrest as a precursor to Iceland's 2021 Fagradalsfjall eruption},
  series = {Nature geoscience},
  volume    = {15},
  journal   = {Nature geoscience},
  number    = {5},
  publisher = {Nature Research},
  address   = {Berlin},
  issn      = {1752-0894},
  doi       = {10.1038/s41561-022-00930-5},
  pages     = {397 -- 404},
  year      = {2022},
  abstract  = {Understanding and constraining the source of geodetic deformation in volcanic areas is an important component of hazard assessment. Here, we analyse deformation and seismicity for one year before the March 2021 Fagradalsfjall eruption in Iceland. We generate a high-resolution catalogue of 39,500 earthquakes using optical cable recordings and develop a poroelastic model to describe three pre-eruptional uplift and subsidence cycles at the Svartsengi geothermal field, 8 km west of the eruption site. We find the observed deformation is best explained by cyclic intrusions into a permeable aquifer by a fluid injected at 4 km depth below the geothermal field, with a total volume of 0.11 ± 0.05 km3 and a density of 850 ± 350 kg m-3. We therefore suggest that ingression of magmatic CO2 can explain the geodetic, gravity and seismic data, although some contribution of magma cannot be excluded.},
  language  = {en}
}