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H2020Individual fellowship2016–2018

IMPACT · Physics of Impact Cratering Collapse

Horizon 2020 — Marie Skłodowska-Curie Actions

Duration
2016-12-15 → 2018-12-14
EU contribution
€159,461
Participants
1
Scheme
MSCA-IF-EF-ST

Lines connect the coordinator with its partners.

Results in brief

Physics of Impact Cratering Collapse

Complex crater collapse is a mechanism still poorly understood, because standard materials models fail to explain the development of central peaks or rings, flat floors and terraced walls from a much deeper and narrower transient cavity. One current model invoked to explain such a collapse is the Acoustic Fluidization (AF) model, which relies in the temporary softening of heavily fractured target rocks by means of an acoustic field in the wake of an expanding shock wave originated upon impact. The Block Model (BM) is one AF simplification, differing from AF for being described by a time-varying Bingham rheology, which depends on viscosity and decay time. Both these two variables were suggested to linearly depend on the projectile radius. However, BM is still lacking of the coupling between the model equations and target properties. A clear understanding of how complex craters form is essential in numerous aspects of planetary geology, including investigation of stratigraphy and composition of the near-surface structure of planetary bodies, derivation of reliable crater-based chronologies, and unravelling the bombardment history on the Earth-Moon system, and the origin and evolution of life on our planet. The overall objective of the project was the improving of the current understanding of the mechanics acting during the final stages of the impact cratering process, and it was fulfilled through a multidisciplinary approach including laboratory experiments and numerical modelling. Both the methodologies were required to comprehensively address the challenge of crater collapse. Laboratory experiments take advantages of direct measure of material response to fluidization, while numerical modelling can simulate assesses the individual effect of any variable on crater formation.

Data: CORDIS, © European Union

Project objective

This research project will study the formation of large meteorite impact craters, characterized by central peaks or rings, flat floors and terraced walls. The complex morphology results from the gravity driven collapse of a much deeper and narrower transient cavity. Standard material models fail to explain such a collapse and specific temporary weakening mechanisms have been proposed. The most successful approach, the Acoustic Fluidization (AF) model, relies on the temporary softening of heavily fractured target rocks by means of an acoustic field in the wake of an expanding shock wave originated upon impact.The project aims to (i) constrain the mechanics of large crater collapse, (ii) constrain AF parameters and enhance AF implementation into simulation software (iSALE), (iii) test the revised AF model with planetary case studies. These objectives will be achieved through a multidisciplinary approach: (1) Small-scale impact experiments will use a target of granular material, which will be acoustically fluidized by an external source to mimic the fluid-like rheology of planetary targets during collapse; (2) Numerical models of complex crater formation, which require the AF parameters to be constrained, will be calibrated and validated against experiments and up-scaled to dimensions of natural craters. The originality lies in combining the systematic laboratory experiments with numerical simulations to improve a widely used AF model.The fulfilment of the project will be ensured by the host and partner institutes, and the planned training activities (laboratory and modelling techniques). The results will be disseminated to the scientific community through peer-reviewed papers and conference contributions. The project will foster excellence in Europe by establishing a network of collaborations that will promote high-quality research, inspire the next generation of planetary scientists, and encourage research in interdisciplinary fields like Solar System exploration.

Original text from CORDIS.

Participants

  • MUSEUM FUR NATURKUNDE - LEIBNIZ-INSTITUT FUR EVOLUTIONS- UND BIODIVERSITATSFORSCHUNG AN DER HUMBOLDT-UNIVERSITAT ZU BERLIN · BerlinCoordinatorGermany

Links

Data: CORDIS, © European Union