Seismic structure of Iceland from Rayleigh wave inversions and geodynamic implications
MetadataShow full item record
We have constrained the shear-wave structure of crust and upper mantle beneath Iceland by analyzing fundamental mode Rayleigh waves recorded at the ICEMELT and HOTSPOT seismic stations in Iceland. The crust varies in thickness from 20 to 28 km in western and northern Iceland and from 26 to 34 km in eastern Iceland. The thickest crust of 34-40 km lies in central Iceland, roughly 100 km west to the current location of the Iceland hotspot. The crust at the hotspot is ~32 km thick and is underlain by low shearwave velocities of 4.0-4.1 km/s in the uppermost mantle, indicating that the Moho at the hotspot is probably a weak discontinuity. This low velocity anomaly beneath the hotspot could be associated with partial melting and hot temperature. The lithosphere in Iceland is confined above 60 km and a low velocity zone (LVZ) is imaged at depths of 60 to 120 km. Shear wave velocity in the LVZ is up to 10% lower than a global reference model, indicating the influence of the Mid-Atlantic Ridge and the hotspot in Iceland. The lowest velocities in the LVZ are found beneath the rift zones, suggesting that plume material is channeled along the Mid-Atlantic Ridge. At depths of 100 to 200 km, low velocity anomalies appear at the Tjornes fracture zone to the north of Iceland and beneath the western volcanic zone in southwestern Iceland. Interestingly, a relatively fast anomaly is imaged beneath the hotspot with its center at ~135 km depth, which could be due to radial anisotropy associated with the strong upwelling within the plume stem or an Mgenriched mantle residual caused by the extensive extraction of melts.
Author Posting. © The Authors, 2005. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Earth and Planetary Science Letters 241 (2006): 901-912, doi:10.1016/j.epsl.2005.10.031.
Showing items related by title, author, creator and subject.
Two-station measurement of Rayleigh-wave phase velocities for the Huatung basin, the westernmost Philippine Sea, with OBS : implications for regional tectonics Kuo, Ban-Yuan; Chi, Wu-Cheng; Lin, Ching-Ren; Chang, Emmy Tsui-Yu; Collins, John A.; Liu, Char-Shine (John Wiley & Sons, 2009-10-28)A broad-band ocean-bottom seismometer (OBS) deployed ~180 km east of Taiwan provides a first glimpse into the upper mantle beneath the westernmost section of the Philippine Sea or the Huatung basin (HB). We measured ...
Asymmetric shallow mantle structure beneath the Hawaiian Swell—evidence from Rayleigh waves recorded by the PLUME network Laske, Gabi; Markee, Amanda; Orcutt, John A.; Wolfe, Cecily J.; Collins, John A.; Solomon, Sean C.; Detrick, Robert S.; Bercovici, David; Hauri, Erik H. (John Wiley & Sons, 2011-10-31)We present models of the 3-D shear velocity structure of the lithosphere and asthenosphere beneath the Hawaiian hotspot and surrounding region. The models are derived from long-period Rayleigh-wave phase velocities that ...
Bhatia, Saurav (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 2012-08)The echo statistics of a randomly rough, randomly oriented prolate spheroid that is randomly located in a beampattern are investigated from physics-based principles both analytically and by Monte Carlo methods. This is ...