This prestigious title is awarded to scientists who have made an exceptional contribution to science and Professor Houseman’s work is certainly deserving of this honour.
Professor Houseman’s research has produced very significant and long-standing advances in geodynamics, which clearly explain the relationship between the governing equations, their critical parameters andsurface measurements. Hiscontributions to the field include showing how convective instabilities link convection and continental dynamics, testing predictions of density structure associated with lower lithosphere removal, and further demonstrating the relationship between the width and length of mountain belts. In recent years, his research has focused on developing new understanding of key geological problemsin the deformation of the Earth’s crust and lithosphere through computer modellingof geological deformation, and using seismic arrays, natural earthquakes and seismic noise to map the 3-D structure of the lithosphere and upper mantle in tectonically active regions like Turkey and Eastern Europe.
Professor Houseman’s work demonstrates that when a continent thickens as tectonic plates converge, convective instabilities can remove the lower lithosphere. This increases the gravitational potential energy of the overlying continent, leading to changes in surface height, volcanism and deformation. This process is now recognised as a fundamental influence on geological activity. By combining satellite observations of ground movement with numerical models at locations including the North Anatolian Fault in Turkey, he has also developed animproved understanding of the earthquake deformation cycle,which is leading towards a better assessment of future seismic hazard.
The many honours bestowed on Professor Houseman for his important contributions to the fieldinclude the European Geophysical Union’s Augustus Love Medal (2015) and Fellowship of the American Geophysical Union (2001), where he was also elected Section President for Tectonophysics (2004-2006). He has been a Fellow of the Institute of Physics since 2004, held a CIRES Fellowship at the University of Colorado at Boulder (2015) and was elected to Academia Europaea in 2016.
COMET would like to congratulate Professor Houseman on receiving his Fellowship of the Royal Society!
Watch the COMET presentation “LiCSAR Catalogue and Response System of Sentinel-1 Earthquake-related Interferograms” from the Seismological Society of America (SSA) 2021 Annual Meeting.
***This studentship is fully funded for UK students through COMET and the BGS***
Project Title: The dynamics of dip-slip faulting across multiple timescales
Supervisory Team:
Dr Tim Craig (University of Leeds – Primary Supervisor)
Dr Ekbal Hussain (British Geological Survey)
Prof. Tim Wright (University of Leeds)
Dr Alex Copley (University of Cambridge)
Dr Laura Gregory (University of Leeds)
Host Institution: University of Leeds, UK.
Deadline: Applications will close on Thursday 22nd April 2021
Figure 1: Exposed fault surface of a active normal fault in Western Anatolia.
Project Summary:
This project aims to understand the factors that control the behaviour of dip-slip faults across a range of timescales, from individual stages of earthquake cycles, to their geological evolution over millions of years. This project will draw on a wealth of new geological and geophysical observations and data, and produce new numerical geodynamic models aimed at understanding the evolution and behaviour of dip-slip faults.
The initial aim for this project will be to analyse geodetic (GPS, InSAR) data to determine the surface motions before, during, and after dip-slip earthquakes. We will then develop models that will allow us to use the observations to infer the rheology and dynamics of the brittle and ductile parts of the crust, using realistic structural and rheological parameters for the fault zone. Of particular interest is how the brittle (and potentially seismogenic) portion of the fault interacts with ductile shear zones at depth, how this interaction controls the geometry and rate of deformation at the timescale of individual earthquake cycles, and how this behaviour ultimately governs the longer-term geological evolution of the fault system and the bounding basins and mountain ranges. An underlying aim of the project will be to use this work to establish how to estimate the pattern of interseismic strain accumulation on active dip-slip fault systems, as a means to improving our understanding of the hazard posed by these faults.
As the project is aimed at understanding globally-applicable concepts, it is geographically unconstrained, but initial target fault systems of interest may include the active fault systems of western United States, eastern Africa, Greece, Italy, Papua New Guinea, and western Anatolia. The initial project is not planned to involve fieldwork, we expect there to be opportunities to participate in fieldwork on related projects in later years.
This initial work coupling geodetic observations to dynamic models of earthquake cycles will not only answer a number of fundamental scientific questions, but will also provide the opportunity for the student to develop relevant observational techniques and skills in numerical geodynamic modelling. Following this initial work, a number of avenues exist to focus on in the later years of the project, depending on the interests and skillset of the student and the nature of the initial results. These include, but are not limited to:
Modelling the evolution of large-offset normal faults, and the impact that increasing footwall erosion and hangingwall sedimentation have on the dynamics of the system, and how this development of the fault system feeds into the longer-term landscape and geological structure.
Constraining the along-strike segmentation of normal fault arrays, and how this may be controlled by shear-zone geometries at depth.
Comparative studies investigating how varying crustal architecture and composition influence the rheological structure of the fault system, and how this impacts on the deformation patterns seen.
Investigating the across-strike migration and transfer of strain amongst dip-slip fault arrays, where multiple faults are active at once.
Modelling the rheological evolution of large-offset detachment faults, and how this impacts their earthquake behaviour.
Should a major dip-slip earthquake of particular interest occur during the duration of the studentship, the student may have the opportunity to work on the scientific response to this event as part of the COMET team.
Performing determinisitic or probabilistic hazard assessments for dip-slip faults, based upon our new results regarding the dynamic controls on their behaviour.
References:
Craig and Parnell-Turner (2017). Depth-varying seismogenesis on an oceanic detachment fault at 13o20’N on the Mid-Atlantic Ridge, EPSL, v479, pp60-70.
Copley et al., (2018). Unexpected earthquake hazard revealed by Holocene rupture on the Kenchreai Fault (central Greece): implications for weak sub-fault shear zones. EPSL, v486, pp141-154.
Biemiller et al., (2020). Mechanical implications of creep and partial coupling on the worlds fastest slipping low-angle normal fault in southeastern Papua New Guinea, JGR, v125, doi:10.1029/2020JB020117.
Hussain et al, (2020). Contrasting seismic risk for Santiago, Chile, from near-field and distant earthquake sources, Natural Hazards and Earth System Sciences, v20, pp1533-1555.
Walters et al., (2018). Dual control of fault intersections on stop-start rupture in the 2016 Central Italy seismic sequence. EPSL, v500, doi: 10.1016/j.epsl.2018.07.043.
Weiss et al., (2020). High-resolution surface velocities and strain for Anatolia from Sentinel-1 InSAR and GNSS data. GRL, v47, pp:e2020GL087376.
Training: The student will work primarily in Leeds under the supervision of Dr Tim Craig, Prof. Tim Wright, and Dr Laura Gregory within the Institute for Geophysics and Tectonics. Regular collaboration with Dr Alex Copley and Dr Ekbal Hussain will be facilitated remotely and by regular visits to the partner institutions, with an expectation that the student would spend longer periods of time at the BGS in Keyworth and in Cambridge as the project requires. The student will receive training in satellite geodesy, observational earthquake seismology and numerical geodynamic modelling. The student will benefit from networking and training available through the NERC-funded Centre for the Observation and Modelling of Earthquakes and Tectonics (www.comet.nerc.ac.uk), with whom the student will be able to interact. Within Leeds, they will have the opportunity to interact with internationally-excellent research groups in Tectonics and Structural Geology, hosted within the Institute for Geophysics and Tectonics.
Applicant Background: This project would suit candidates with a background in quantitative geology, geophysics, or physics with an interest in solid-Earth processes. Prior skills in computer programming, observational geodesy, seismology or numerical geodynamic modelling are desirable, but not required.
To apply: For further information, and to discuss the project and applications, please contact t.j.craig@leeds.ac.uk, and include your current CV.
COMET Director Professor Tim Wright will present a free public lecture, ‘Monitoring our hazardous planet from space’, as part of the Royal Astronomical Society’s Bicentenary celebrations
This lecture is part of the free and open to the public lecture series for the Royal Astronomical Society’s bicentenary celebrations and will take place online.
In the last twenty years, earthquakes have caused the deaths of nearly 1 million people and volcanic activity has resulted in hundreds of thousands of people being evacuated from their homes. These events also cause major economic disruption, with aftereffects ranging from the destruction of buildings and infrastructure to airspace closures. Scientists in COMET* are at the forefront of international efforts to monitor our hazardous planet using satellites. COMET scientists are now providing critical information to decision makers around the world so that they can prepare for and quickly respond to earthquakes and eruptions. In this lecture, I will show how satellites are used to monitor tiny ground movements with extraordinary accuracy and explain how understanding these movements can help us forecast where future earthquakes will occur and when volcanoes might erupt.
*COMET is the UK Natural Environment Research Council’s Centre for the Observation and Modelling of Earthquakes, Volcanoes and Tectonics.
Main Event image: A building that collapsed during the January 2020 Turkey earthquake, which occurred in one of the high strain zones. Photo courtesy Roger Bilham, University of Colorado.
About the speaker:
Tim Wright is Professor of Satellite Geodesy at the University of Leeds and Director of COMET. His work has been at the forefront of developing the use of satellite radar for measuring tectonic and volcanic deformation. He was the first to measure the slow accumulation of tectonic strain around active faults with satellite radar, and he is currently leading a major project using the latest satellites to map how all the continents are deforming. In 2018 he co-founded a spinout company, Satsense Ltd, which is monitoring ground movement in the UK at high resolution. Tim has received several awards for his work including the 2014 Geodesy Section Award from the American Geophysical Union, the 2015 Bullerwell Lectureship from the British Geophysical Association, and the 2017 Harold Jeffreys Lectureship from the Royal Astronomical Society. In 2018, COMET was awarded the Royal Astronomical Society’s Group Achievement award in Geophysics.
How satellite InSAR has grown from opportunistic science to routine monitoring over the last decade
COMET Deputy Director (Volcanoes), Prof. Juliet Biggs, and COMET Director, Prof. Tim Wright, have written a commentary on satellite InSAR for the 10 year anniversary of
Nature Communications out in print! Read the article here.
An orbiting satellite sends a coherent radar signal to the surface and measures the backscattered radiation. The phase difference (position in the wave cycle) between the signals returning at two different times (time 1 in black and time 2 in red) can be used to estimate ground movement caused by a range of mechanisms. https://www.nature.com/articles/s41467-020-17587-6/figures/1
An international group of research scientists including COMET researchers Prof. Tim Wright (COMET Director) and Prof. Andy Hooper, and led by Freysteinn Sigmundsson at the University of Iceland’s Institute of Earth Sciences, has presented a new method for evaluating when molten magma in volcano roots becomes unstable and forces its way towards the surface of the Earth. In an article published in the prestigious journal Nature Communications, the method is used to better understand precursors, onset and evolution of a large-volume eruption in Iceland in 2014-2015.
Just over five years have passed since the end of the 2014-2015 Holuhraun eruption in the Bardarbunga volcanic system; an eruption that produced the largest lava field in Iceland for more than 200 years. The data gathered in the time leading up to the eruption and during it has proven a valuable source for new discoveries in earth sciences in recent years, and now for improved understanding of magma movements in volcano roots.
In the study published in Nature Communications the group of scientists shed light on what conditions need to be in place in a volcano for an eruption to start, and furthermore how eruptions develop and lead to caldera formation, i.e. when a large part of a volcano subsides at the same time as a large amount of magma reaches the surface, as was the case in the 2014-2015 activity.
“Previous methods to understand magma movements in the surface have certain limitations and are based on assumptions that are not always applicable. It is also noteworthy that some large-volume eruptions have small or minor precursors in terms of increased earthquake activity and magma movements. Small eruptions can on the other hand have large precursors. This is not what is expected from commonly used models that volcanologists have used to interpret monitoring data from volcanoes,” Freysteinn points out.
The research consisted of developing a new method to take jointly into consideration three important effects that influence how magma accumulates and then forces its way to the surface.
Firstly, magma may be less dense than the host rock surrounding it. Where magma accumulates in volcano roots it can therefore have a large upward directed buoyancy force. “This means that if sufficient magma accumulates, this force alone can break the surrounding host rock and magma can flow upwards,” explains Freysteinn.
Secondly, the host rock around magma bodies in volcano roots can behave as a ductile material. It can deform and flow in a ”viscoelastic manner” – such that solid rocks yields away from the magma and creates space for new magma without fracturing. This can happen if magma accumulates over long time, many years or still longer time periods.
“Finally, it must be considered that magma can form pipe-like pathways e.g. by eroding away part of surrounding rocks where magma flows. Such sustained magma channels do not easily close, even if pressure drops in underlying magma bodies that feed these magma channels. This means that following the peak of an eruption such a channel can thus remain open for considerable time,” adds Freysteinn.
By connecting these three factors together into one methodology a new approach to understand magma movements was created. The method was then applied to the Iceland unrest and large-scale eruption in 2014-2015 to demonstrate its applicability. “The series of events can be explained by the existence of magma below Bárðabunga for a long time prior to the eruption. The rock surrounding the magma yielded creating space for the magma. Evaluation of the magma and rock’s density shows that the magma could easily flow upwards. The magma was thus almost ready to burst forward, needing only a small inflow of additional magma to start the eruption. Thus a sustained magma channel was formed from the magma accumulation area resulting in a large drop in pressure leading to the caldera formation in Bárðarbunga,” explains Freysteinn.
The results are important as the method developed can be applied to all volcanoes. “The method points to certain features that scientists and those who monitor volcanoes need to consider when estimating if a new eruption will begin. Large eruptions can occur with only minor precursory activity,” concludes Freysteinn.
COMET has been awarded £950,000 by NERC to deliver cutting-edge research on earthquakes and volcanoes and to continue the development of hazard monitoring services.
NERC has officially announced the new funding for COMET on Wednesday 29 May. This will enable ambitious, large-scale science which helps us to understand global change and natural disasters over the next two years.
NERC National Capability lets the UK deliver world-leading environmental science, support national strategic needs, and respond to emergencies. It includes major research infrastructure and facilities, large-scale, long-term research programmes, and the provision of expert advice and services for public and national good.
You can read more about the award, and National Capability, on the NERC website.
Work led by COMET scientists Juliet Biggs and Andy Hooper is developing new methods for using artificial intelligence and satellite data monitor and potentially help predict volcanic eruptions.
Their work is described in a Nature article, published on 7 March 2019, which outlines how Juliet’s team at Bristol is using satellite imagery from the European Space Agency Sentinel-1 mission, alongside machine learning, to spot the formation of ground distortions around volcanoes.
Agung volcano on the Indonesian island of Bali erupts in November 2017. Credit: Donal Husni/Zuma
Meanwhile at Leeds, Andy’s team is using a technique that searches for changes in the satellite data. Where the ground around a volcano is deforming, their method can flag if the distortion speeds up, slows down, or changes in some other way, allowing researchers to detect even small ground alterations.
The outstanding contributions of COMET UCL’s Professor Marek Ziebart to the science of space navigation, guidance and control have been recognised with a prestigious award from the US Institute of Navigation.
The Tycho Brahe Award is bestowed annually to an individual who has made a truly significant contribution to the science of spacecraft navigation and whose actions have benefited civilisation in any form.
Marek, who is Professor of Space Geodesy in the UCL Department of Civil, Environmental and Geomatic Engineering, focuses on the design of innovative navigation systems for spacecraft, including a navigation and communications system for manned and robotics missions to Mars and the moon between 2020 and 2040.
The US Institute of Navigation cited his outstanding innovation and leadership in the area of high precision, physics-based radiation force modelling for spacecraft orbit dynamics. His work has revolutionised the precision of satellite orbit modelling and led to a long running and successful collaboration with NASA Goddard Space Flight Center, where his methods have been applied to many NASA missions, including the Jason-1 satellite of the Ocean Surface Topography Mission to measure Earth’s sea levels.
Professor Ziebart said: “In receiving this award I’d like to acknowledge the help and support of my colleagues and the faculty at UCL. To me it seems that in this extraordinary institution you get smarter simply by osmosis. I feel privileged to be a part of UCL and working on research that is truly impactful and beneficial to the planet as a whole.”
The award was presented at a ceremony at the US Institute of Navigation in Washington on 31st January, 2019.
The achievements of four COMET scientists have been recognised in a recent spate of prizes!
Juliet Biggs, Reader at the University of Bristol, has been announced as a 2018 Philip Leverhulme Prize Winner, recognising her outstanding research in volcanology to date and future potential.
Juliet studies the physics by which plate boundaries develop by studying active volcanoes and earthquakes. Her work on Africa’s Great Rift Valley has demonstrated the relative role played by volcanoes, magma intrusions and faults during continental rifting.
Globally, she has discovered that many volcanoes previously believed to be dormant are actually restless, and investigated the link between deformation and eruption, and the mechanisms for coupled eruptions. Her work has changed the perception of geophysical hazards in Africa and the way in which volcanoes are monitored and modelled globally.
Juliet will use the prize to investigate the mechanisms that drive volcano deformation globally, by exploiting the new wealth of satellite data. This will include methods for combining satellite deformation and gas measurements to provide a new perspective on the role volatiles play in eruptions, and using deep learning tools to interrogate large datasets.
This award recognises her achievements in the field of volcanology as well as her ability to communicate with the public. Tamsin delivered the Rosalind Franklin Award Lecture on 18 October, speaking on how lessons learned sitting on the edge of an active volcano today can give us insights into some of the most profound environmental changes in geological history. With her award, Tamsin will now be implementing a project that raises the profile of women in STEM.
This is given every two years in recognition for “original contributions to the basic knowledge of crust and lithosphere.” Professor England will be awarded his medal at the AGU Fall Meeting later this year.
Finally, our congratulations go to the 2019 Thermo-Fisher Scientific VMSG awardee, Dr Marie Edmonds, Reader in Earth Sciences at the University of Cambridge.
This award is bestowed annually on an individual who has made a significant contribution to our current understanding of volcanic and magmatic processes, and Marie will give the VMSG keynote lecture in January 2019.
