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Dr Ake Fagereng

Dr Ake Fagereng

Reader

School of Earth and Environmental Sciences

Email
fagerenga@cardiff.ac.uk
Telephone
+44 (0)29 2087 0760
Campuses
2.09, Main Building, Park Place, Cardiff, CF10 3AT
Users
Available for postgraduate supervision

Overview

Interests

My interests are in how the Earth deforms and how this deformation is recorded in rocks. I typically observe rocks cropping out on the Earth's surface, but I also participate in drilling projects that collect samples underground. I am interested in both plate boundaries and plate interiors; specifically the range of seismic styles (from creep, through slow slip events, to giant earthquakes) in subduction zones, how rifts form and are controlled (or not) by pre-existing structures, why there are large earthquakes far from plate boundaries, and the interplay between fluids (water and melt) and deformation.

I explore these topics through field investigations of active and ancient deformation structures, microstructural investigation of deformed rocks, and a range of geochemical and imaging techniques.

Keywords:

  • Structural geology
  • Faults
  • Subduction
  • Rifting
  • Earthquakes
  • Slow slip and tremor

Biography

  • Reader in Structural Geology – School of Earth and Ocean Sciences, Cardiff University (2017 - present)
  • Honorary Research Fellow – Department of Geological Sciences, University of Cape Town (2014-present)
  • Lecturer in Structural Geology – School of Earth and Ocean Sciences, Cardiff University (2014 - 2017)
  • Lecturer/Senior Lecturer  – Department of Geological Sciences, University of Cape Town (2010-2014)
  • PhD – Department of Geology, University of Otago (2010)
  • BSc(Hons) Geology – University of Cape Town (2005)

Honours and awards

  • Outstanding Young Scientist Award, European Geosciences Union, Division of Tectonics and Structural Geology (2016)
  • International Visiting Fellow, Kyoto University, Japan (2016)
  • Excellent Reviewer Award from Earth, Planets, and Space (2015)
  • American Geophysical Union, Geophysical Research Letters, Editor's Citation for Excellence in Refereeing (2013)
  • President's Award, National Research Foundation, South Africa (2013)
  • Elsevier Young Scientist Award (2013)
  • Claude Leon Foundation Merit Award for Young Lecturers (2012)
  • University of Cape Town College of Fellows' Young Researcher Award (2012)

Professional memberships

  • American Geophysical Union
  • Geological Society of America
  • Geological Society of London
  • Geological Society of Norway

Speaking engagements

  • Royal Society Meeting on Earthquakes in the Geological Record (Invited talk, 2020)
  • European Geosciences Union (Invited talks in 2016 and 2019, contributed talk in 2017)
  • Geological Society of America Annual Meeting (Invited presentation, 2017)
  • The 35th International Geological Congress, Cape Town (Keynote and Theme Champion, 2016)
  • Joint Workshop on Slow Earthquakes, Japan (2015, 2017, 2018)
  • Geological Society of London Tectonic Studies Group Meeting (2014, 2015, 2016, 2017)
  • Gordon Conference on Rock Deformation (Keynotes in 2014 and 2018)
  • AGU Fall Meeting (session convenor 2013, 2014, 2016, 2018, 2019; invited talks in 2010, 2011, 2013, 2015; contributed talks 2007, 2014, 2016, 2018, 2019;  contributed poster 2008, 2009)
  • GeoPRISMS New Zealand meeting (2013)
  • Africa Array Conference (2012, 2014)
  • Penrose Conference on Convergent Margins (2012, invited talk)
  • IODP workshop on ocean drilling and slow slip events (2011)
  • Penrose Conference on Deformation Localization (2011)
  • Earthscope Institute on the spectrum of fault slip styles (2010)
  • Igneous and Metamorphic Studies Group (GSSA) (2010, 2012)
  • New Zealand Geosciences (session convenor 2009, speaker 2007, 2008, 2009)
  • Public lectures at MTN Science Centre, Cape Town and U3A Hermanus, South Africa
  • Departmental Seminars at California Institute of Technology, Cambridge University, ETH Zurich, Imperial College London, Plymouth University, University of California Santa Cruz, University of Cape Town, University of Edinburgh, University of Leeds, University of Otago  
  • Research Group Seminars at Bristol University, California Institute of Technology, the Geological Survey of Japan, and Oxford University

Committees and reviewing

  • Associate Editor, Gophysical Research Letters (2015 - present)
  • Member of the Ramsay Medal committee, Tectonics Studies Group of the Geological Society of London (2016, 2017 [chair], 2018) 
  • Member of the Editorial Advisory Board, Journal of Structural Geology (2014 - present)
  • Accreditation Committee, University of Cape Town (2011 - 2013)
  • Journal reviewer, Earth and Planetary Science Letters, Earth Planets Space, G-Cubed, Geofluids, GSA Bulletin, GSA Special Papers, Geological Society of London Special Publications, Geology, Geophysical Research Letters, Gondwana Research, International Geology Reviews, Journal of Geophysical Research, Journal of Marine and Petroleum Geology, Journal of Structural Geology, Journal of the Geological Society of London, Nature Communications, Nature Geoscience, Precambrian Research, Pure and Applied Geophysics, Science China, South African Journal of Geology, Tectonics, Tectonophysics
  • Grant reviewer, National Commission for Scientic and Technological Research (Chile),National Geographic, National Research Foundation (South Africa), National Science Foundation (USA), Natural Environment Research Council (UK), and Netherlands Organisation for Scientic Research

Publications

2020

2019

2018

2017

2016

2015

2014

2013

2012

2011

2010

2009

2008

Teaching

I am a fellow of the Higher Education Academy. I teach across the undergraduate programmes in the School of Earth and Ocean Sciences, primarily supporting Geology and Exploration and Resource Geology students.

My teaching is focused on structural geology, but also larger scale tectonics and geodynamics, and BSc and MSci Dissertation Projects. You're also likely to find me teaching in the field. 

In 2020/21 I have a reduced teaching load because of my focus on the ERC MICA project. However, I expect to be involved in developing and teaching Structural Geology and Geophysics at year 2, and support field teaching.

During my time in Cardiff, I have been involved in teaching the following:

  • Introduction to Geological Maps, Sections, and Structures (year 1)
  • Structural Geology (year 2) and Structural Techniques (year 3)
  • Geodynamics (years 3 and 4)
  • Residential field courses on structural geology, including focus on structural controls on mineral deposits (in Cornwall for year 2 and in north Wales for year 3) and mapping training in Spain at the end of year 2. I have also participated in teaching the final year field course (in Cyprus). 
  • I was Director of Fieldwork from 2015 to 2018. 

Prior to working in Cardiff, I was a Senior Lecturer in the Department of Geological Sciences at the University of Cape Town. There, I taught structural geology at BSc and BSc(Hons) level, geology to civil engineers, and supervised several BSc(Hons) and MSc projects.

I am a structural geologist, and my research is based on observations of natural faults and shear zones. I divide my work in two key themes, the way faults slip (earthquakes vs creep vs other slip styles) and how faults grow and are reactivated. Both these themes are relevant to where earthquakes may occur and how large such events may be. 

Fault slip behaviour

I currently focus a lot of my time on the ERC-funded MICA project, which was recently described in Horizon Magazine. The project is designed to explore the geological processes that control fault slip speed, and the varied behaviour of faults that accommodate tectonic deformation in the Earth's crust. These faults slip at a range of speeds from millimetres per year, a rate comparable to fingernail growth, up to metres per second, a rate that generates earthquakes. In the last two decades, observations from GPS and seismometer networks have shown that faults also slip at rates intermediate between these end-members, in events now known as 'slow earthquakes'.

The physical processes that control fault slip rate are poorly understood. It is, for example, currently unknown how slow and fast earthquakes are related. Critical questions of societal importance include: If a fault experiences slow earthquakes, can it also experience earthquakes that are damaging? If parts of a fault experiences a slow earthquake, does this increase (or decrease) the probability of a damaging earthquake nearby? Can slow earthquakes accelerate and become fast and damaging? The MICA project seeks to identify the effects of fault zone thickness, internal geometry, and composition. This is done through detailed fieldwork and laboratory studies of rocks from fault zones exposed on the Earth's surface, or accessible through ocean drilling. Based on field and microscale observations, we create models for realistic geometry and deformation mechanisms in major fault zones. From these models, we identify variables that control slip speed, and allow slip at a range of speeds. These hypotheses are tested by numerical and laboratory deformation experiments.

Key samples were collected during IODP Expedition 375 to New Zealand's Hikurangi subduction margin. You can read my shipboard blog on what ocean drilling may tell us about fault zone geology and mechanics. We have published the geology of the Pāpaku fault, which may host active slow slip, and on how heterogeneous sediments and ocean floor topography may control subduction thrust slip behaviour. My article in The Conversation explains some of this research, and this article in Futurum Careers provides an educational resource on working as a ship-board geologist. 

Other key outcomes of this project include

  • Stress amplification occurs within a heterogeneous shear zone and can be quantified with a numerical model of a two-phase viscous shear zone, as published by Beall et al in GRL (2019), and further applied to slow slip events when including fractures in the model, as by Beall et al. in G-Cubed (2019).
  • Subducting oceanic crust, if hydrated and altered, can be as weak as the sediments on top of it, as explained by Tulley et al in Science Advances (2020)
  • The dense vein networks that are commonly observed in exhumed accretionary prisms may be the total, integrated effect of many local, fluid-driven fracture episodes in a relatively small depth range - similar to tremor in active subduction zones, as discussed based on the Kuiseb Schist in Fagereng et al. (Geology, 2018).
  • Although phyllosilicates are often the weakest component of a shear zone, they may not be interconnected at high strains, and instead deformation may be controlled by the fine-grained reaction products that deform easily by diffusion - as Stenvall et al. (2019) explain in their GRL article 'Weaker than weakest'. 

Faults, fault growth, and fault reactivation

I have now been working in the East African Rift System for several years, particularly in the southern, amagmatic, Malawi Rift. One point of interest here is how ancient structures may control fault growth and earthquake occurrence. This work has been funded by the EPSRC's Global Challenges Research Fund, in the PREPARE project - a collaboration between Engineering and Earth Sciences at the Universtities of Bristol and Cardiff, aimed at enhancing earthquake resilience in East Africa. 

While the Malawi project explores an incipient plate boundary, I am also interested in faults that form far from plate margins, such as end- and post-glacial faults that host earthquakes in response to retreating glaciers. I am a PI of the project DAFNE (Drilling Active Faults in Northern Europe) that aims to drill into the post-glacial Pärvie fault in northern Sweden. This project is supported by funds from the International Continental Scientific Drilling Program (ICDP).

Supervision

I am interested in supervising PhD and Masters students. See past projects below for the sort of topics I tend to supervise, which are in the general areas of

  • Structure and mechanics of subduction zones
  • Hydrothermal vein systems
  • Fault zone structure
  • Development and rheology of shear zones
  • Links between geological and geophysical observations

I am also happy to co-supervise structural geology elements of broader projects.

Current students

  • Sara de Caroli - Failing under pressure: exploring the frictional-viscous transition in cold subduction zones
    • Funded by a Cardiff University College of Physical Sciences and Engineering Studentship and the European Reseach Council
  • Sophie Cox - Development, deformation style, and seismic hazard of oceanic transform faults
    • Funded by the NERC GW4 Doctoral Training Programme
  • Harold Leah - Mechanical evolution, fluid pressure generation, and shallow slow slip in subduction zones
    • Fundend by the European Research Council
  • Christopher Tulley - The geology of deep slow slip and tremor: Instability in the viscous regime?
    • Funded by the European Research Council
  • Niall Groome (co-supervised) - Origin of Precambrian accreted oceanic sequences in North Wales
    • Funded by KESS (Knowledge Economy Skills Scholarships)

Past students:

PhD:

  • Christian Stenvall (PhD 2020, lead supervisor) - Sources and effects of fluids in continental retrograde shear zones
    • Now at Boliden Mineral AB, Sweden
  • Michael Hodge (PhD, 2018, lead supervisor) - Development, deformation style, and seismic hazard of large normal faults
    • Now at the Office for National Statistics

MESci:

  • Manon Carpenter (2020, co-supervisor) - How do faults grow in continental rifts?
  • Paul Edwards (2020, co-supervisor) - What controls the variation in earthquake magnitude between subduction zones with subducted seamounts?
  • Stephen James (2019, co-supervisor) - When faults become shear zones: Modelling the frictional-viscous transition
  • Aled Evans (2017, lead supervisor) - Fluid flow and mineralization along long-lived and reactivated fault zones: The example of the Carmel Head thrust, Anglesey, North Wales
  • Dylan Ingman (2016, lead supervisor) - Stresses and strain localisation processes in Maud Belt mylonites

MSc at Univeristy of Cape Town:

  • Leslie Huang (2017, co-supervisor) - Pre-Rift evolution of Malawian high-grade basement rocks
  • Kaylan Hamel (2016, lead supervisor) - Fluid-rock interaction in the Colenso Fault Zone, Saldania Belt, South Africa
  • Gregory Byrnes (2015, co-supervisor) - Structural and Metamorphic History of Sverdrupfjella, Antarctica
  • Michael Hartnady (2014, lead supervisor) - Deformation history of the Southern Marginal Zone, Damara Belt, Namibia
  • Sukey Thomas (2014, co-supervisor) - Melt migration as recorded in Sverdrupfjella, Maud Belt, Antarctica
  • David McGibbon (2014, lead supervisor) - Shear zones of the Maud Belt, Antarctica - Kinematics and deformation mechanisms
  • Louis Smit (2014, lead supervisor) - Microseismic monitoring of the Ceres-Tulbagh region, Western Cape, South Africa
  • Clayton Cross (2013, co-supervisor) - Metamorphic history of the Matchless Amphibolite, Damara Belt, Namibia
  • Matthew Hodge (2013, lead supervisor) - Neotectonics of the Southern Cape

Current supervision

Sophie Cox

Sophie Cox

Research student

Harold Leah

Harold Leah

Research student

Christopher Tulley

Christopher Tulley

Research student

Sara De Caroli

Research student

Niall Groome

Niall Groome

Research student