Seismic efficiency for simple crater formation in the Martian top crust analogue
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Author(s)
Type
Journal Article
Abstract
The first seismometer operating on the surface of another planet was deployed by the NASA InSight (Interior Exploration using Seismic Investigations, Geodesy and Heat Transport) mission to Mars. It gives us an opportunity to investigate the seismicity of Mars, including any seismic activity caused by small meteorite bombardment. Detectability of impact generated seismic signals is closely related to the seismic efficiency, defined as the fraction of the impactor's kinetic energy transferred into the seismic energy in a target medium. This work investigated the seismic efficiency of the Martian near surface associated with small meteorite impacts on Mars. We used the iSALE‐2D (Impact‐Simplified Arbitrary Lagrangian Eulerian) shock physics code to simulate the formation of the meter‐size impact craters, and we used a recently formed 1.5 m diameter crater as a case study. The Martian crust was simulated as unfractured nonporous bedrock, fractured bedrock with 25% porosity, and highly porous regolith with 44% and 65% porosity. We used appropriate strength and porosity models defined in previous works, and we identified that the seismic efficiency is very sensitive to the speed of sound and elastic threshold in the target medium. We constrained the value of the impact‐related seismic efficiency to be between the order of ∼10‐7 to 10‐6 for the regolith and ∼10‐4 to 10‐3 for the bedrock. For new impacts occurring on Mars, this work can help understand the near‐surface properties of the Martian crust, and it contributes to the understanding of impact detectability via seismic signals as a function of the target media.
Date Issued
2021-02
Online Publication Date
2021-03-23T10:09:22Z
Date Acceptance
2021-01-19
ISSN
2169-9097
Publisher
American Geophysical Union (AGU)
Start Page
1
End Page
12
Journal / Book Title
Journal of Geophysical Research: Planets
Volume
126
Issue
2
Copyright Statement
© 2021. The Authors.
This is an open access article under the terms of the Creative Commons Attribution‐NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.
This is an open access article under the terms of the Creative Commons Attribution‐NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.
Sponsor
Science and Technology Facilities Council (STFC)
Science and Technology Facilities Council (STFC)
Identifier
https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2020JE006662
Grant Number
ST/S001514/1
ST/T002026/1
Subjects
0201 Astronomical and Space Sciences
0402 Geochemistry
0403 Geology
Publication Status
Published
Date Publish Online
2021-01-25