Lead supervisor: Nicholas Rawlinson, Earth Sciences
Co-supervisor: Sergei Lebedev, Earth Sciences
Brief summary:
The goal of this project is to combine advanced earthquake detection and location techniques together with seismic imaging methods to track melt migration and delineate melt storage regions beneath Askja Volcano in Iceland.
Importance of the area of research concerned:
Askja is a large central volcano situated within the Northern Volcanic Zone (NVZ) of Iceland, which in 1875 produced one of the largest eruptions in Iceland’s historical record, and last erupted in 1961. Since the early 1970s, it has been gradually deflating, but in August 2021, InSAR and GPS measurements confirmed a switch to reinflation after ~50 years. The Cambridge Volcano Seismology Group (CVSG) has operated a large backbone array in the NVZ since 2007, resulting in an unprecedented dataset that spans ~15 year of deflation and the switch to reinflation. Recently, a dense array of seismic stations and nodes were deployed within Askja caldera to capture reinflation seismicity in detail. This combined dataset provides a unique oipportunity to study changes in the magmatic plumbing system beneath a large central volcano in a rift setting.
Project summary :
The aim of the project is to apply microseismic hypocentre mapping and seismic tomography to track melt movement through the crust using existing and recently acquired seismic data from Askja caldera and the surrounding NVZ. It is already known that the switch to reinflation was accompanied by a sginificant increase in seismicity, but detailed detection and location is required in order to determine whether new melt pathways were generated, and seismic imaging is needed to locate shallow melt storage regions. In this project, the student will use absolute and relative relocation techniques to accurately constrain the distribution of seismicity in time and space, and apply targeted imaging methods that focus on localised perturbations in Vp/Vs, which may be a signature of melt intrusion in the crust.
What will the student do?:
The student will join an experienced fieldwork team in servicing our broad-band seismometer array in the NVZ and Askja caldera, and help integrate new data with our existing catalogue of seismic data in the region. They will then assemble and groom a high quality dataset that can be used for microseismic detection and imaging. The Quakemigrate package developed at Cambridge will be the primary detection tool and seismic imaging packages such as FMTOMO can be applied to retrieve information on perturbations in velocity structure, including Vp/Vs. This project would best suit a student with solid computational skills, and a willingness to modify pre-existing code as needed. They will also interact with other students and staff at the Department who are also studying this region using other methods such as geobarometry to measure the ascent of melt through the crust.
References - references should provide further reading about the project:
White, R. S., Edmonds, M., Maclennan, J., Greenfield, T. & Ágústsdóttir, T. (2018). Melt movement through the Icelandic crust, Proceedings of the Royal Society, Series A, 377, 20180010, doi: 10.1098/rsta.2018.0010
Volk, O., White, R. S., Pilia, S., Green, R. G., Maclennan, J. & Rawlinson, N. (2021). Oceanic crustal flow in Iceland observed using seismic anisotropy, Nature Geosciences, vol 14, 168-173.
Greenfield, T., White, R. S., and Roecker, S. (2016), The magmatic plumbing system of the Askja central volcano, Iceland, as imaged by seismic tomography, J. Geophys. Res. Solid Earth, 121, 7211–7229.
Applying
You can find out about applying for this project on the Department of Earth Sciences page.