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Thorbjorg (Tobba) Agustsdottir


  • BSc in Geophysics, University of Iceland.
  • MSc in Geophysics, University of Iceland.
  • Part time research and teaching assistant at the University of Iceland.
  • Currently PhD student in Volcano Seismology at University of Cambridge.
  • High level athlete from high school to PhD.
  • Captain of Cambridge University Fencing Club Women Blues Team

Research Interests

Volcanology, Seismology, Geodynamics and Tectonics 

Cambridge Volcano Seismology at the Royal Society Summer Science Exhibition - @ExplosiveEarth 

I am a part of the Cambridge Volcano-Seismology group investigating shallow crustal seismicity in Iceland, lead by Professor Bob White. The data we work with is collected with our local passive seismic network in central Iceland. This network is run by us in the Cambridge University Volcano-Seismology group in collaboration with the University of Iceland, and is supported by grants and equipment loans from the Natural Environment Research Council. We study earthquakes in and around volcanoes in the Northern and Eastern Volcanic Zones in Iceland where the plate spreading is accommodated by rifting events. Our dense network is focused around Askja volcano and surrounding Vatnajökull ice cap and its many volcanoes. 

We explore many applications of volcano seismology, from what we can learn about movement of magma in the earth's crust and rift zone dynamics, to the very structure of the earth itself. Our current research focus is central Iceland where they operate an extensive seismic network. Tiny earthquakes are often detected under volcanoes prior to eruption, caused by the movement melt beneath the surface.  

  • My research focuses on the microseismicity accompanying the Bárðarbunga-Holuhraun dyke intrusion, investigating the 30,000 earthquakes that led up to a spectacular six-month eruption in Holuhraun. The earthquakes tracked the progress of the magma as it moved away underground from the subglacial volcano Bárðarbunga to the eventual eruption site Holuhraun 46 km away. My research is also focused on the seismicity associated with the 2014-15 Holuhraun eruption and the subsidence of the feeder volcano Bárðarbunga caldera.  

 You can follow me @fencingtobba


Bárðarbunga-Holuhraun Dike Intrusion 2014

2014-15 Bárðarbunga-Holuhraun fissure eruption



Holuhraun eruption by nightOver a two weeks period in August 2014 magma propagated laterally for 48 km from the sub-glacial Bárðarbunga volcano in the northern rift zone , to the Holuhraun lava field. The dyke intrusion created more than 30,000 earthquakes at 5‒7 km depth as the magma forced its way through the earths crust before erupting on 29 August 2014. The spectacular fissure eruption lasted 6 months and erupted 1.4km3 over an area of 85 km2. Our dense seismic network recorded the dyke intrusion, eruptive seismicity and the subsidence of Bárðarbunga caldera in unprecedented detail. Which allows us to obtain very accurate earthquake locations and study in detail the failure mechanisms of these earthquakes as well as getting a better understanding of a rifting event in general by studying the earthquake distribution, size and more.


Fieldwork in Iceland

Holuhraun fissure eruption 31.08.2014 Station deployment at the dyke tip two days prior to the eruption.

Our research in Iceland wouldn't be possible without our collaboration with Bryndís Brandsdóttir at the Institute of Earth Science, University of Iceland, and the unmatched field skills of Sveinbjörn Steinthorsson. My PhD studentship is funded by FutureVolc and I am supervised by Professor Bob White. The National Environment Research Council has funded much of our research in Iceland and many of the instruments are loaned from SEIS-UK.

Iceland - Cambridge researchers:

  • Bob White, Tim Greenfield, Rob Green, Thorbjörg Ágústsdóttir, Jenny Woods, Jenny Jenkins, Tom Hudson, Clare Donaldson, David Pugh, Juerg Schuler, Corentin Caudron, Bryndís Brandsdóttir, Sveinbjörn Steinthórsson.


Research Supervision

I am supervised by Professor Robert White


Volcanology ; Seismology


  • Volcanology
  • Seismology

Key Publications

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