The structure and seismicity of Icelandic rifts ...

• Main Author: Green, Robert George
• Format: Thesis
• Language: English
• Published: Apollo - University of Cambridge Repository 2016
• Subjects: Ambient noise tomography; Iceland; Stress triggered seismicity; Stress shadow; Coloumb stress; Bookshelf faulting; Rift zone; Northern Volcanic Zone; velocity model
• Online Access: https://dx.doi.org/10.17863/cam.8916; https://www.repository.cam.ac.uk/handle/1810/263564

Three-fifths of the Earth’s crust has been built at oceanic spreading centres in the last 160 million years. To explore crustal extension processes and the architecture of these constructive plate boundaries I have studied the oceanic rift in Iceland. Here the Mid Atlantic Ridge is anomalously elevated above sea level and thus easier to instrument. I have deployed and operated a dense network of seismometers in the remote volcanic highlands in central Iceland, and used the passive seismic data collected from this network to explore crustal structure and volcanic processes in the extensional rift zones. My analysis of persistent seismicity located in an intervening region between individual spreading segments, uniquely records the segmentation of plate spreading on the scale of individual volcanic systems. Precise location and characterisation of micro-earthquakes identifies a series of faults subparallel to the rift fabric, and source mechanisms define left-lateral strike-slip motion on these faults. This ...