About me

orcid.org/0000-0002-1614-7133

My research is focused on processes occurring in volcanic systems, using seismology to study volcanic activity occurring beneath the surface, and structure of the plumbing systems that feed volcanoes. I attempt to combine seismological studies with other geophysical observables to build a better understanding of activities going on beneath the surface at volcanoes. I have previously worked on the seismic structure and seismicity of the extensional volcanic rifts in Iceland, and the crustal response of earthquakes triggered by stresses during the 2014 Bárðarbunga-Holuhraun dyke intrusion. My current research project at the GFZ-Potsdam is part of the KISS project, studying the seismic structure and eruptive seismic signals of the Klyuchevskoy volcanic group in Kamchatka, Russia. GFZ-Potsdam webpage

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Publications

Crustal formation on a spreading ridge above a mantle plume: receiver function imaging of the Icelandic crust. Jenkins, J., Maclennan, Green, R.G., Cottaar, S., Deuss, A.F., White, R.S. Journal of Geophysical Research, 123, 5190–5208 (2018). https://doi.org/10.1029/2017JB015121

Dynamics of the Askja caldera July 2014 landslide, Iceland, from seismic signal analysis: precursor, motion and aftermath. Schöpa, A., Chao, W., Lipovsky, B. Hovius, N., White, R. S., Green, R. G., Turowski, J. M. Earth Surf. Dynam., 6, 467–485 (2018). https://doi.org/10.5194/esurf-6-467-2018

Seismic Amplitude Ratio Analysis of the Bárðarbunga-Holuhraun dike propagation and eruption. Caudron. C., White. R. S., Green. R. G., Woods. J., Ágústsdóttir. Th., Donaldson. C., Greenfield. T., Rivalta. E., Brandsdóttir. B. Journal of Geophysical Research,, 123, 264–276 (2018). https://doi.org/10.1002/2017JB014660

Deep crustal melt plumbing of Bárðarbunga volcano, Iceland. Hudson. T. S., White. R. S., Greenfield. T., Ágústsdóttir. Th., Brisbourne. A., Green. R. G. Geophysical Research Letters, 44, 8785–8794 (2017). http://dx.doi.org/10.1002/2017GL074749 Download PDF

Relative seismic velocity variations correlate with deformation at Kilauea volcano. Donaldson. C., Caudron. C., Green. R. G., Thelen. W. A., White. R. S. Science Advances, 3, e1700219 (2017). https://doi.org/10.1126/sciadv.1700219 Download PDF

Ambient noise tomography reveals upper crustal structure of Icelandic rifts. Green. R. G., Priestley. K. P., White. R. S. Earth and Planetary Science Letters, 466, 20–31 (2017). http://doi.org/10.1016/j.epsl.2017.02.039 Download PDF

Strike-slip Faulting during the 2014 Bárðarbunga-Holuhraun Dike Intrusion, Central Iceland. Ágústsdóttir. Th., Woods. J., Greenfield. T., Green. R. G., White. R. S., Winder. T., Brandsdóttir. B., Steinthórsson. S., Soosalu. H. Geophysical Research Letters, 43 (2016). http://dx.doi.org/10.1002/2015GL067423 Download PDF

Triggered earthquakes suppressed by an evolving stress shadow from a propagating dyke. Green. R. G., Greenfield. T., White. R. S. Nature Geoscience, 8, 629–633 (2015). http://doi.org/10.1038/ngeo2491 Download pre-print

Segmented lateral dyke growth in a rifting event at Bárðarbunga volcanic system, Iceland. Sigmundsson, F., Hooper, A., Hreinsdóttir, S., Vogfjörd, K.S., Ófeigsson, B.G., Heimisson, E.R., Dumont, S., Parks, M., Spaans, K., Gudmundsson, G.B., Drouin, V., Árnadóttir, T., Jónsdóttir, K., Gudmundsson, M.T., Högnadóttir, T., Fridriksdóttir, H.M., Hensch, M., Einarsson, P., Magnússon, E., Samsonov, S., Brandsdóttir, B., White, R.S., Ágústsdóttir, T., Greenfield, T., Green, R.G., Hjartardóttir, Á.R., Pedersen, R., Bennett, R.A., Geirsson, H., La Femina, P.C., Björnsson, H., Pálsson, F., Sturkell, E., Bean, C.J., Möllhoff, M., Braiden, A.K., Eibl, E.P.S. Nature, 517, 191–195 (2015). http://doi.org/10.1038/nature14111 View shared epdf

Motion in the north Iceland volcanic rift zone accommodated by bookshelf faulting. Green. R. G., White. R. S. & Greenfield. T. Nature Geoscience, 7, 29–33 (2014). http://doi.org/10.1038/ngeo2012 Download pre-print

Download PhD Thesis

The structure and seismicity of Icelandic rifts. Green. R. G., University of Cambridge, (2016). Please cite the papers.

My CV

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Research

Bárðarbunga-Holuhraun 2014 dyke intrusion:

In late August 2014, as initial earthquakes and ground deformations signalled unrest at Bárðarbunga volcano in central Iceland, we were able to respond immediately to deploy seismometers to monitor the volcanic unrest as it unfolded. An intrusion of magma propagated horizontally through the subsurface at a depth of ∼2-8km for a distance of 45 km before it erupted at Holuhraun on 29th August. Small earthquakes occurring towards the tip of the magma as the rock fractured ahead of it allow us to track the migration of the magma intrusion through the subsurface. As the magma propagated we installed more seismometers ahead of its projected path, and so we have been able to record the earthquakes of this volcanic eruption in unprecedented detail. The eruption of 29th August was short lived, but the fissure eruption began again on 31st August and did not end until 28th February. An estimated 1.4 cubic km of lava was erupted over six months covering an area of over 85 km2 (the same as Manhattan). During this period thousands of small earthquakes were recorded at the northern end of the dyke where it fed the fissure eruption at the surface. We are currently using this data to investigate the process by which this magmatic dyke fractured its way through country rock and how it came to the surface. We have also used the dataset to investigate triggering of earthquakes in the surrounding volcanoes.

“Installing seismic stations at a safe distance from the spectacular fire fountains”

“This seismic station was installed just hours before the magma erupted”

Earthquake Triggering during Dyke propagation:

As the magmatic dyke propagated the deformation stressed the surrounding crust, and this effect was particularly felt at some of nearby volcanos. Using the seismicity to map the location of the dyke in the subsurface, and GPS measurements to model how much it opened we can calculate the stress changes felt at these nearby volcanic areas. As the stress increased the number of earthquakes in these locations increased, and then as soon as the stressing rate became negative the earthquakes in these regions were completely suppressed. This effect (known as a “stress shadow effect”) has been typically hard to demonstrate in the past but is remarkably clear here.
Green et al. Nature Geoscience,(2015). http://doi.org/10.1038/ngeo2491

Velocity structure of the Icelandic crust

I have used surface wave dispersion from ambient noise cross correlation to produce velocity models for all of Iceland, with excellent resolution across the Vatnajökull icecap region and the Northern Volcanic Zone.
Green et al. Earth and Planetary Science Letters, (2017). http://doi.org/10.1016/j.epsl.2017.02.039

Earthquakes at Askja and Bookshelf Faulting near Herðubreið:

In the region of the rhyolitic central volcano Askja, over 5000 micro-earthquakes (less than M3) are detected and located annually. Persistent seismicity occurs beneath a hydrothermal field in the caldera, and episodic earthquake activity is seen at depths of greater than 15km below the volcano. Most of the micro-seismicity however occurs in swarms or bursts of activity, beneath the table mountain of Herðubreið, which I have mapped as excellently constrained strike-slip faults. The bookshelf faults and their associated rotations represent the accommodation of the expected right-lateral transform shear between two overlapping spreading centres.
Green et al. Nature Geoscience, (2014). http://doi.org/10.1038/ngeo2012

Fieldwork in Iceland – Maintaining and developing the monitoring network

“Retrieving stations from Vatnajökull icecap”

“Deploying stations in Askja volcano caldera”