Active Development of Continental Rifts: Wide Swath Interferometry in East Africa.
Lead Research Organisation:
University of Bristol
Department Name: Earth Sciences
Abstract
We like to think of the ground as a solid, immovable platform in an uncertain world, but even the continents are slowly drifting beneath our feet; the patterns of land and sea constantly changing. East Africa is being gradually pulled apart by the forces of plate tectonics - eventually there will be a new ocean, but at the present day, we can already see the beginnings: the three thousand kilometre long Great Rift Valley containing a string of volcanoes and prone to earthquakes. But what happens next? The established view is that stretching takes place during earthquakes as two blocks slide past each other on faults. Yet recent satellite observations have shown that magma is important. Imagine sliding apart two pieces of wood stacked on top of each other - the forces of friction resist you. Now imagine the pieces of wood are floating on a pond: this is a much easier task, there is less friction and the water flows to fill the gap. This is similar to what happens in East Africa - the presence of magma alters the way in which the continent stretches. Scientists are working on a new paradigm, one in which magma plays a crucial role in continental rifts. Before new models can be developed, we need a clear set of observations against which to test them. Currently only a few case studies are available - yet we need to see the patterns of magma and fault movement throughout the rift: Is the stretching focused on the faults or near the volcanoes the centre of the valley? How much magma is there? Magma rises in short pulses, like drips, but what controls how these drips form? The best way to begin answering these questions is to use satellite observations - avoiding the need for time-consuming expeditions to remote and dangerous terrain. Using satellite-based radar, it is possible to cover hundreds of kilometres of the rift with a single image and detect small amounts of uplift or subsidence associated with stretching and magma moving underground. Once particular areas of concern have been identified, ground-based instruments can be used to provide more detailed observations on individual examples. Using the archive of large satellite images, I will analyse ground movement spanning 7 years and covering the length of the rift, from Ethiopia to Malawi. These observations will describe the pattern of faulting and magma movement in space and time, allowing the development of a new class of continental rifting models, to include the effects of magma. In addition to these scientific goals, this project will generate information on what is currently an underestimated source of potential hazard and we will communicate the results to local and global management bodies.
People |
ORCID iD |
Juliet Biggs (Principal Investigator) |
Publications
Biggs J
(2016)
The lateral extent of volcanic interactions during unrest and eruption
in Nature Geoscience
Biggs J
(2013)
Surface deformation and stress interactions during the 2007-2010 sequence of earthquake, dyke intrusion and eruption in northern Tanzania
in Geophysical Journal International
Evans AJ
(2019)
Exciting Times: New Advances Towards Understanding the Regulation and Roles of Kainate Receptors.
in Neurochemical research
Hutchison W
(2016)
Causes of unrest at silicic calderas in the East African Rift: New constraints from InSAR and soil-gas chemistry at Aluto volcano, Ethiopia
in Geochemistry, Geophysics, Geosystems
Hutchison W
(2015)
Structural controls on fluid pathways in an active rift system: A case study of the Aluto volcanic complex
in Geosphere
Lavayssière A
(2018)
Imaging Lithospheric Discontinuities Beneath the Northern East African Rift Using S-to-P Receiver Functions.
in Geochemistry, geophysics, geosystems : G(3)
Liu D
(2017)
Damage tolerance of nuclear graphite at elevated temperatures
in Nature Communications
Lloyd R
(2019)
The decade-long Machaze-Zinave aftershock sequence in the slowly straining Mozambique Rift
in Geophysical Journal International
Lloyd R
(2018)
Evidence for cross rift structural controls on deformation and seismicity at a continental rift caldera
in Earth and Planetary Science Letters
Masson J
(2017)
Achieving positive change for children? Reducing the length of child protection proceedings: lessons from England and Wales
in Adoption & Fostering
Description | The findings have demonstrated that deformation is widespread at volcanoes within the East African Rift with significant implications for volcanic hazard and the rapidly-expanding geothermal industry. It has also raised questions about the interpretation of volcano deformation on a global scale, and the provision of satellite data to the developing world. |
Exploitation Route | This grant has inspired further funding from numerous sources (see further funding information) |
Sectors | Energy Environment Government Democracy and Justice |
Description | The findings have demonstrated that deformation is widespread at volcanoes within the East African Rift with significant implications for volcanic hazard and the rapidly-expanding geothermal industry. It has also raised questions about the interpretation of volcano deformation on a global scale, and the provision of satellite data to the developing world. It developed methods of using WideSwath SAR data for tectonics applications which have been applied to the recently launched Sentinel-1 mission. |
Sector | Energy,Environment |
Impact Types | Economic |
Description | Exploring Global Patterns of Volcanic Deformation with Satellite Radar. |
Amount | £15,000 (GBP) |
Organisation | The Royal Society |
Sector | Charity/Non Profit |
Country | United Kingdom |
Start | 03/2013 |
End | 04/2014 |
Description | NERC GEF Equipment Loan |
Amount | £81,000 (GBP) |
Funding ID | 992 |
Organisation | Research Councils UK (RCUK) |
Sector | Public |
Country | United Kingdom |
Start | 03/2013 |
End | 04/2014 |
Description | NERC GEF Equipment Loan |
Amount | £81,000 (GBP) |
Funding ID | 992 |
Organisation | Research Councils UK (RCUK) |
Sector | Public |
Country | United Kingdom |
Start | 03/2013 |
End | 03/2015 |
Description | RiftVolc (NERC Large Grant) |
Amount | £584,072 (GBP) |
Funding ID | NE/L01372X/1 |
Organisation | Natural Environment Research Council |
Sector | Public |
Country | United Kingdom |
Start | 08/2014 |
End | 09/2019 |
Description | IGSSA |
Organisation | Addis Ababa University |
Department | Institute of Geophysics, Space Science and Astronomy (IGSSA) |
Country | Ethiopia |
Sector | Academic/University |
PI Contribution | Co-organised field programmes and import/export of equipment. Spent 1 month teaching a course on InSAR for MSc students. Co-supervised a MSc research project. Joint interpretation of scientific results |
Collaborator Contribution | Co-organised field programmes and import/export of equipment. Local knowledge (including both scientific knowledge of rift tectonics, techniques such as GPS and logistics) Joint interpretation of scientific results |
Impact | Joint publications Joint funding |
Start Year | 2012 |
Description | University of Nairobi |
Organisation | University of Nairobi |
Country | Kenya |
Sector | Academic/University |
PI Contribution | Co-organised a field campaign and sample export |
Collaborator Contribution | Co-organised a field campaign and sample export Arranged meetings with Ministry of Mines |
Impact | Joint publications |
Start Year | 2012 |
Description | InSAR course for MSc Geodesy Class at Addis Ababa University |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Public/other audiences |
Results and Impact | A one-month intensive course on using InSAR to students on an MSc in Geodesy programme at Addis Ababa University. The participants have gone back to their respective countries in East Africa and several continue to use InSAR, and several remain in contact. |
Year(s) Of Engagement Activity | 2012 |
Description | New Scientist Article |
Form Of Engagement Activity | A press release, press conference or response to a media enquiry/interview |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Public/other audiences |
Results and Impact | Article inspired by a talk given at the Royal Astronomical Society, and based on further interviews. |
Year(s) Of Engagement Activity | 2013 |