Formation of complex craters in layered targets with material anisotropy
File(s)
Published version
Author(s)
Hopkins, Ryan T
Osinski, Gordon R
Collins, Gareth S
Type
Journal Article
Abstract
Meteorite impacts often occur in layered targets, where the strength of the target varies as a function of depth, but this complexity is often not represented in numerical impact simulations because of the high computational cost of resolving thin layers. To address this limitation, we developed a method to approximate the effect of multiple thin weak layers within a sedimentary sequence using a single material layer to represent the entire sequence. Our approach, implemented in the iSALE (impact‐Simplified Arbitrary Lagrangian Eulerian) shock physics code, combines an anisotropic yield criterion with a cell‐based method to track the orientation of layers. To demonstrate the efficacy of the method and constrain parameters of the anisotropic strength model required to replicate the effects of thin, weak layers, we compare results of simulations of a ~20 – 25‐km diameter complex crater on Earth using the new method to those from simulations that explicitly resolve multiple thin weak layers. We show that our approach allows for a reduction in computational cost, negating the need for an increase in spatial resolution to resolve thin layers in the target, while replicating crater formation and final morphology from the high‐resolution models. In keeping with field observations, we also find that anisotropic layers may be responsible for a lack of central uplift expression observed at many craters formed in targets with thick sedimentary layers (e.g., the Haughton and Ries impact structures).
Date Issued
2019-02
Date Acceptance
2019-01-06
Citation
Journal of Geophysical Research: Planets, 2019, 124 (2), pp.349-373
ISSN
2169-9097
Publisher
American Geophysical Union (AGU)
Start Page
349
End Page
373
Journal / Book Title
Journal of Geophysical Research: Planets
Volume
124
Issue
2
Copyright Statement
©2019. American Geophysical Union.
All Rights Reserved.
All Rights Reserved.
Sponsor
Science and Technology Facilities Council (STFC)
Grant Number
ST/N000803/1
Subjects
Science & Technology
Physical Sciences
Geochemistry & Geophysics
impact cratering
anisotropy
complex craters
shock-physics code
IMPACT CRATER
ACOUSTIC FLUIDIZATION
HYDROCODE SIMULATIONS
TECTONICS
INSIGHT
RUSSIA
Publication Status
Published
Date Publish Online
2019-01-12