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Understanding subduction zone topography through modelling of coupled shallow and deep processes

Periodic Reporting for period 2 - SUBITOP (Understanding subduction zone topography through modelling of coupled shallow and deep processes)

Reporting period: 2018-03-01 to 2020-02-29

The surface of the Earth is sculpted by erosion acting on continents formed and uplifted by tectonic processes. One of the most important tectonic processes is subduction, whereby oceanic lithosphere bends and plunges into the deep mantle. Subduction is the engine of plate tectonics, recycling water, CO2 and crustal material in the Earth’s interior, sustaining mantle convection and global heat transport. It also has a strong societal impact. Subduction zones harbour the largest natural hazards on Earth, including great earthquakes (Mw >8), related tsunamis and explosive volcanic eruptions. Coastal regions affected by these hazards are often densely populated. At longer timescales, the evolution of topography over subduction zones is a critical factor governing long-term climate change, global geochemical cycles and biodiversity. It is of particular interest to Europe, where subduction has shaped many of the most prominent topographic features. One aspect of subduction research, which has not received adequate attention is the topographic evolution of subduction margins. The scientific programme is focused on this question in a forward sense (predicting topography) and an inverse sense (interpreting topography in terms of process). Our main goals are:
1. to advance understanding of how surface processes interact with crustal tectonics and mantle convection in subduction zones in Europe, including the interactions between physical processes at different length- and time- scales;
2. to train 15 early stage researchers (ESRs) in state-of-the-art concepts and leading-edge research techniques, while providing them with strong career management skills and solid professional connections;
3. to increase the impact and international visibility of European research by structuring the research and training capacities via long-term collaboration and synergy among ten research teams internationally recognised for their excellence in complementary fields of Earth Sciences.
The scientific work is organised within two Science Work Packages (WP) as summarised in figure 1. WP1 is dedicated to prediction and forecasting of surface topography and shallow deformation through modelling of deep processes, based on numerical or analogue models. Coupled dynamic models are being developed and applied. WP2 is directed at unravelling the signal of geodynamic processes from surface observations. Natural European subduction test sites have been selected representing a range of tectonic processes. Across these two WPs, all ESRs have refined their initial project strategy; they have acquired an overview of the state-of-the-art, learned existing analogue and numerical modelling approaches and developed new ones to suit specific research needs, ran models exploring key aspects of subduction zone dynamics, and collected geological data to constrain the major physical processes.
The SUBITOP training programme aims to raise a cohort of creative, entrepreneurial and innovative ESRs through theoretical and practical training in state-of-the-art concepts and techniques, by fostering strong organisational, presentation, team-building, networking and management skills, and by securing experience of the private sector. Two workshops and three short courses have been organised to give the ESRs these key qualifications. The five events have focused on the geodynamics of subduction systems; the geology, tectonics and geomorphology of back arc extension in Greece; numerical modelling of shallow and deep subduction processes, analogue modelling of shallow processes in subduction zones; and the formulation of sound research strategies for individual ESR projects and the development of synergies between these projects. Career development consisted so far in the formulation and regular updates of personalised development programmes; regular coaching by supervisors; and the appointment and action of a tutor.
Relations with private sector partners has aimed to ensure that academic – private sector partnerships are effective across the ETN, to secure participation of private sector representatives in training activities, and to guarantee ESRs access to all private sector partners in the Network. Partnerships have been adjusted in response to personnel developments, and to optimize the link between the developing ESR projects and their industry hosts. Representatives of SUBITOP private sector partners have attended and actively contributed to the two SUBITOP workshops to date. Relations with other ITNs ensures optimal coordination of research and training opportunities, and to facilitate mutual participation of ESRs in selected training activities in SUBITOP and other ITNs. We have identified 3 ITNs with relevant research and training opportunities, and informed the coordinators of these networks about opportunities for their ESRs in SUBITOP. Given the heavy training schedules of all ITNs, there is limited interest in cross-participation in network events, but at each of the SUBITOP events open to external participants, we have hosted four or five external students.
Communication of SUBITOP results was addressed so far by SUBITOP ESRs presenting their work at at least one major conference, or are about to do so, convening a scientific session at the 2018 European Geosciences Union Assembly. First paper manuscripts are in preparation. The SUBITOP website contains frequently updated information and provides access to the Subito! newsletter, entirely produced by the ESRs. A series of social media accounts have been set up for use by the network. Outreach work consists importantly of the operation of an ESR-school class partnership. All ESRs have had at least one round of interactions and have received coaching on teaching during the second SUBITOP workshop. Five teachers have attended SUBITOP workshops and short courses.
The management of the SUBITOP network secures effective relations and exchange of information with the EU-REA and the Network Beneficiaries and Partners: reports, amendments, financial redistribution; implementation of the Consortium Agreement, IPR rules and confidentiality agreements; organisation of meetings; definition and assessment of SUBITOP best practice guidelines; position advertising and recruitment; monitoring of ESR progress, training and career development plans; and promotion of gender balance within the Network.
SUBITOP research is advancing understanding of how surface processes interact with crustal tectonics and mantle convection in subduction zones including the interactions between physical processes at different length- and time- scales, with special attention to the subduction systems dominating the topography and natural hazards of Europe. Multidisciplinary, observational and laboratory constraints on geological features drive multi-scale numerical and analogue models designed to identify and test major parameters governing the links and feedback between deep and surface processes. Model predictions are, in turn, tested against geological and geomorphological data. The WPs associate ESR projects addressing basic research questions and projects with more immediate industrial applications or societal impact. Thus, SUBITOP fosters interactions between young and senior researchers working on the applications of mantle convection, crustal deformation and surface processes on active margins in a large range of research fields in both academia and industry.
Processes at work during subduction, highlighting the surface response to deep processes.