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dc.contributor.authorGreen, Roberten
dc.contributor.authorPriestley, Keithen
dc.contributor.authorWhite, Roberten
dc.description.abstractThe structure of oceanic spreading centres and subsurface melt distribution within newly formed crust is largely understood from marine seismic experiments. In Iceland, however, sub-aerial rift elevation allows both accurate surface mapping and the installation of large broadband seismic arrays. We present a study using ambient noise Rayleigh wave tomography to image the volcanic spreading centres across Iceland. Our high resolution model images a continuous band of low seismic velocities, parallelling all three segments of the branched rift in Iceland. The upper 10 km contains strong velocity variations, with shear wave velocities 0.5 km s$^{−1}$ faster in the older non-volcanically active regions compared to the active rifts. Slow velocities correlate very closely with geological surface mapping, with contours of the anomalies parallelling the edges of the neo-volcanic zones. The low-velocity band extends to the full 50 km width of the neo-volcanic zones, demonstrating a significant contrast with the narrow (8 km wide) magmatic zone seen at fast spreading ridges, where the rate of melt supply is similarly high. Within the seismically slow rift band, the lowest velocity cores of the anomalies occur above the centre of the mantle plume under the Vatnajökull icecap, and in the Eastern Volcanic Zone under the central volcano Katla. This suggests localisation of melt accumulation at these specific volcanic centres, demonstrating variability in melt supply into the shallow crust along the rift axis. Shear velocity inversions with depth show that the strongest velocity contrasts are found in the upper 8 km, and show a slight depression in the shear velocity through the mid crust (10–20 km) in the rifts. Our model also shows less intensity to the slow rift anomaly in the Western Volcanic Zone, supporting the notion that rift activity here is decreasing as the ridge jumps to the Eastern Volcanic Zone.
dc.description.sponsorshipSeismometers were borrowed from the Natural Environment Research Council (NERC) SEIS-UK (loans 968 and 1022). The work was funded by a graduate studentship from the NERC and research grants from the NERC (grants NE/F01140711, NE/M017427/1, NE/H025006/1) and the European Community's Seventh Framework Programme Grant No. 308377 (FUTUREVOLC) ... IMAGE project has received funding from the European Union's Seventh Programme for research, technological development and demonstration under grant agreement number 608553. Stations for this project were provided by the Geophysical Instrument Pool of Potsdam (GFZ). Dept. Earth Sciences, Cambridge contribution number ESC3818.
dc.rightsAttribution 4.0 Internationalen
dc.rightsAttribution 4.0 Internationalen
dc.rightsAttribution 4.0 Internationalen
dc.rightsAttribution 4.0 Internationalen
dc.rightsAttribution 4.0 Internationalen
dc.subjectambient noise tomographyen
dc.subjectseismic structureen
dc.subjectspreading centreen
dc.subjectmid-ocean ridgeen
dc.titleAmbient noise tomography reveals upper crustal structure of Icelandic riftsen
prism.publicationNameEarth and Planetary Science Lettersen
dc.contributor.orcidGreen, Robert [0000-0002-1614-7133]
dc.contributor.orcidWhite, Robert [0000-0002-2972-397X]
rioxxterms.typeJournal Article/Reviewen
pubs.funder-project-idNERC (NE/F011407/1)
pubs.funder-project-idNERC (NE/H025006/1)
pubs.funder-project-idNERC (NE/M017427/1)
pubs.funder-project-idEC FP7 CP (308377)

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Attribution 4.0 International
Except where otherwise noted, this item's licence is described as Attribution 4.0 International