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A new crater near inSight: implications for seismic impact detectability on Mars

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Title: A new crater near inSight: implications for seismic impact detectability on Mars
Authors: Daubar, IJ
Lognonné, P
Teanby, NA
Collins, GS
Clinton, J
Stähler, S
Spiga, A
Karakostas, F
Ceylan, S
Malin, M
McEwen, AS
Maguire, R
Charalambous, C
Onodera, K
Lucas, A
Rolland, L
Vaubaillon, J
Kawamura, T
Böse, M
Horleston, A
Driel, M
Stevanović, J
Miljković, K
Fernando, B
Huang, Q
Giardini, D
Larmat, CS
Leng, K
Rajšić, A
Schmerr, N
Wójcicka, N
Pike, T
Wookey, J
Rodriguez, S
Garcia, R
Banks, ME
Margerin, L
Posiolova, L
Banerdt, B
Item Type: Journal Article
Abstract: A new 1.5 meter diameter impact crater was discovered on Mars only ~40 km from the InSight lander. Context camera images constrained its formation between February 21 and April 6, 2019; follow‐up HiRISE images resolved the crater. During this time period, three seismic events were identified in InSight data. We derive expected seismic signal characteristics and use them to evaluate each of the seismic events. However, none of them can definitively be associated with this source. Atmospheric perturbations are generally expected to be generated during impacts; however, in this case, no signal could be identified as related to the known impact. Using scaling relationships based on the terrestrial and lunar analogs and numerical modeling, we predict the amplitude, peak frequency, and duration of the seismic signal that would have emanated from this impact. The predicted amplitude falls near the lowest levels of the measured seismometer noise for the predicted frequency. Hence it is not surprising this impact event was not positively identified in the seismic data. Finding this crater was a lucky event as its formation this close to InSight has a probability of only ~0.2, and the odds of capturing it in before and after images is extremely low. We revisit impact‐seismic discriminators in light of real experience with a seismometer on the martian surface. Using measured noise of the instrument, we revise our previous prediction of seismic impact detections downwards, from ~a few to tens, to just ~2 per Earth year, still with an order of magnitude uncertainty.
Issue Date: 1-Aug-2020
Date of Acceptance: 2-Jul-2020
URI: http://hdl.handle.net/10044/1/81870
DOI: 10.1029/2020je006382
ISSN: 2169-9097
Publisher: American Geophysical Union (AGU)
Journal / Book Title: Journal of Geophysical Research: Planets
Volume: 125
Issue: 8
Copyright Statement: ©2020. American Geophysical Union. All Rights Reserved.
Sponsor/Funder: Science and Technology Facilities Council (STFC)
Science and Technology Facilities Council (STFC)
Funder's Grant Number: ST/S001514/1
Keywords: 0201 Astronomical and Space Sciences
0402 Geochemistry
0403 Geology
Publication Status: Published
Article Number: e2020JE006382
Online Publication Date: 2020-07-11
Appears in Collections:Earth Science and Engineering
Faculty of Engineering