Project 6

Crater structure and excavation: the effects of water, porosity, and target layering

Project directors:

Thomas Kenkmann, Insitute for Geosciences, University Freiburg (ALU)
Alex Deutsch, Institute for Planetology, Westfälische Wilhelms-Universität Münster (WWU)
Klaus Thoma, Fraunhofer Institute for High-Speed Dynamics, Ernst-Mach-Institut (EMI)

Research staff:

Frank Sommer (PhD student, ALU)
Markus Arnold (student assistant, ALU)
Michael Rudolf (student assistant, ALU)

Summary

The surface of the Earth and other planetary bodies is covered to a large degree by sedimentary rocks (including, for example, regolith-breccias) that therefore represent a very important target lithology for impacts. These rocks are porous and often layered, and may contain interstitial water; these parameters affect magnitude and absorption of shock waves and influence the cratering process.

This project is aimed at quantification of the effects of these parameters in cratering experiments with sedimentary rocks as targets. We will monitor and analyze the (I) dynamics of crater growth and ejecta flow, determine (II) crater morphometry and cratering efficiency as function of porosity, pore water, and layering, and investigate (III) shock metamorphism of the ejecta and map shear zones in the crater floor. The obtained data will yield a phenomenological quantification of the various effects, and provide a reference scheme for the numerical simulations of the experiments (MEMIN project 5). Our results will be scaled to strength-dominated natural impact craters.

Results

You can find the results here.