E. Glastonbury-Southern, T. Winder, N. Rawlinson, R. S. White, T. Greenfield, C. A. Bacon, T. Ágústsdóttir, B. Brandsdóttir, E. Á. Gudnason, G. P. Hersir, T. J. Fischer, J. Doubravová, P. Hrubcová, E. P. S. Eibl
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引用次数: 0
Abstract
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° with a standard deviation of 2° in the southern segment, and 046° with a standard deviation of 1° 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.
期刊介绍:
The Journal of Geophysical Research: Solid Earth serves as the premier publication for the breadth of solid Earth geophysics including (in alphabetical order): electromagnetic methods; exploration geophysics; geodesy and gravity; geodynamics, rheology, and plate kinematics; geomagnetism and paleomagnetism; hydrogeophysics; Instruments, techniques, and models; solid Earth interactions with the cryosphere, atmosphere, oceans, and climate; marine geology and geophysics; natural and anthropogenic hazards; near surface geophysics; petrology, geochemistry, and mineralogy; planet Earth physics and chemistry; rock mechanics and deformation; seismology; tectonophysics; and volcanology.
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