Ambient noise tomography reveals upper crustal structure of Icelandic rifts ...

• Main Authors: Green, RG, Priestley, KF, White, RS
• Format: Article in Journal/Newspaper
• Language: English
• Published: Elsevier 2017
• Subjects: Iceland; ambient noise tomography; seismic structure; spreading centre; mid-ocean ridge
• Online Access: https://dx.doi.org/10.17863/cam.9525; https://www.repository.cam.ac.uk/handle/1810/264166

The 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 ...