By the end if the course the student will:
- understand the fundamental principles underlying various approaches to modelling tectonic processes and deformation of the lithosphere;
- have strongly advanced into conceptualizing crustal-scale tectonic problems and converting these into modelling strategies;
- have gained insight in the key rheological processes governing the deformation of the crust and the lithosphere;
- have gained knowledge on how to use modelling and how to interpret modelling results for the benefit of understanding deformation of natural laboratories;
- have been exposed to the basic skills required for building analogue and computer models or to apply different modelling techniques;
- have developed a critical understanding of the benefits and limitations of the various modelling approaches.
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Please Note: Due to space limitations in the laboratory, where half of the course will be taught, this course is limited to 20 students and admission is upon evaluation of motivation letters, which have to be sent by e-mail to the course coordinator the latest by June 30, 2017.
The course consists of interconnected components that elucidate various aspects of how crust and lithosphere deformation processes can be studied through the application of physical analogue and numerical modelling techniques. The course starts with a discussion on modelling as a means for studying earth system processes followed by an overview of modelling techniques and a review of crust-lithosphere rheology. Next, the analogue modelling approach is extensively used to illustrate general aspects of modelling (how to build a model, choice of initial and boundary conditions, scaling etc.) and to infer basic modes of crust and lithosphere deformation in contraction and extension. The simplified case study addresses deformation of the Aegean-Anatolian region as derived from field geological observations and kinematic reconstructions and is used to demonstrate the importance of various boundary conditions. The next part of the course introduces analytical and numerical modelling approaches to studying deformation of the crust-lithosphere. The case study of the Aegean-Anatolian region is further addressed with thin visco-elastic sheet modelling. As such the “case study” serves as an important connecting element of the course. Lastly, 2-D modelling of a vertical section of the crust-lithosphere system forms the starting point for investigating first order relations between visco-plastic-elastic rheology, the geotherm, fault motion, various lateral forcings of the system, and topography change. The course is structured into two parts:
1. Physical analogue modelling:
- Basics of physical analogue modelling.
The students will get acquainted with the principles of analogue modelling including the rheology of analogue materials, scaling of the experiments, and how to build models, elaborate on their simplifications and underlying assumptions.
- Frictional behaviour and its implication on fault and orogenic wedge geometries.
Simple, crustal-scale models, build with frictional materials will be used to discuss orogenic wedge geometries as a function of variable basal friction boundary conditions.
- Principles of coupling vs. decoupling for deformation of the crust and lithosphere.
As the rheological stratification of the crust and the lithosphere govern important aspects of deformation such as strain localization, the geometry, style and sequence of deformation, etc., brittle-ductile experiments will be deployed to study deformation geometries in relation to the degree of coupling among layers constituting the crust and the lithosphere. The results will be discussed in the frame of: styles of rifting (wide rifts vs narrow rifts with application to Aegean region) and the geometry of Alps-type mountain belts.
- Case study – Anatolia escape.
This exercise includes all aspects named above and highlights the 3d aspects of crust and lithosphere deformation. Students will have to build experiments tailored towards investigating the kinematics of lateral escape of Anatolia; detailed analysis of surface deformation through particle tracing will enable to compare modelling results with GPS data and numerical modelling predictions, acquired during 2nd part of this course.
2. Numerical modelling and micro-physical approach to modelling deformation
- Introduction to thin visco-elastic sheet modelling of lithosphere deformation.
The students will set up a visco-elastic plane stress model of Anatolia and Greece to investigate the influence of the forcing (slab rollback, Arabia collision, Nubia convergence, gravitational potential energy, …), vertically averaged lithospheric rheology, and friction on major regional faults on the fit to observations (GPS benchmark motions, focal mechanisms, uplift/subsidence ….). One particular discussion item will be the earthquake cycle and its geodetic expression.
- Introduction to 2-D visco-plastic modelling of a 2-D vertical section of the lithosphere.
In numerical experiments the initial conditions (model layering, rheology of the lithosphere, faults rheology, and the geotherm) as well as the boundary conditions (various velocity and stress conditions) will be varied to investigate the stress and deformation response of the lithosphere as well as topography change. Special attention is directed to which rheological component is dominant and to deformation localization on creeping faults.
- Modelling of fault strength.
The student will use existing flow laws to construct crustal strength profiles for the upper ~30 km of the crust as well as incorporate additional flow laws based on microphysical models derived from laboratory experiments. Phenomenological friction laws will be discussed and used in a boundary-element numerical code to simulate the seismic cycle and to investigate the effect of varying parameters on earthquake recurrence and size.
Development of transferable skills:
Leadership and teamwork: Students work in teams; in order to get the assignments done the teams need to organize themselves and chose a leader (leadership can change). At the same time, close collaboration among team members is needed to successfully complete the assignments.
Written communication skills will be acquired through presenting the results of the assignments in short, publication style reports.
Problem-solving skills: applying modelling techniques intrinsically demands the development of problem solving skills to be able to convert a research questions into meaningful modelling concept with sound initial and boundary conditions.
Analytical/quantitative skills: students have to quantitatively analyze and interpret modelling results and critically discuss their findings with published data and concepts.
Flexibility/adaptability: Depending on outcome of the modelling exercises students will have to adopt their modelling strategies, anticipating on previous success or failure.
Technical skills: the students will learn new techniques (physical analogue and numerical modelling) for tackling scientific problems.
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