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A New Crater Near InSight: Implications for Seismic Impact Detectability on Mars

Daubar, I. J. and Lognonné, Philippe and Teanby, N. A. and Collins, G. S. and Clinton, J. and Stähler, S. and Spiga, Aymeric and Karakostas, F. and Ceylan, S. and Malin, M. and McEwen, A. S. and Maguire, R. and Charalambous, C. and Onodera, K. and Lucas, A. and Rolland, L. and Vaubaillon, J. and Kawamura, T. and Böse, M. and Horleston, A. and Driel, M. and Stevanović, J. and Miljković, K. and Fernando, B. and Huang, Q. and Giardini, D. and Larmat, C. S. and Leng, K. and Rajšić, A. and Schmerr, N. and Wójcicka, N. and Pike, T. and Wookey, J. and Rodriguez, S. and Garcia, Raphaël F. and Banks, M. E. and Margerin, L. and Posiolova, L. and Banerdt, William Bruce A New Crater Near InSight: Implications for Seismic Impact Detectability on Mars. (2020) Journal of Geophysical Research: Planets, 125 (8). ISSN 2169-9097

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Official URL: https://doi.org/10.1029/2020JE006382

Abstract

A new 1.5 m diameter impact crater was discovered on Mars only ~40 km from the InSight lander. Context camera images constrained its formation between 21 February and 6 April 2019; follow‐up High Resolution Imaging Science Experiment 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 are 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 downward, from ~a few to tens, to just ~2 per Earth year, still with an order of magnitude uncertainty.

Item Type:Article
Audience (journal):International peer-reviewed journal
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Institution:Université de Toulouse > Institut Supérieur de l'Aéronautique et de l'Espace - ISAE-SUPAERO (FRANCE)
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Deposited On:12 Jan 2022 10:05

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