Martian regolith structures revealed by broadband-frequency events

<p>Planetary regolith is important to understand the environmental evolution of planets, which is always one of main topics in planetary landers, like Apollo Program, Tianwen mission, Perseverance Rover, and InSight mission (Zhang et al., 2021). Being familiar with planetary regolith in advance is probably benefit for the migration of human beings, from Earth to other planets, for example whether there is a potential water layer in the regolith or not (Yoldi et al., 2015). Many ways can be used to investigate regolith, including ground-penetrating radar, visible/near-infrared spectrometer, and seismometer, and so on, among which seismic detection can discern the deepest regolith structure.</p> <p>In this work, we employed broadband-frequency seismic event 1222 detected by InSight mission (InSight Mars SEIS Data Service., 2019) to study the Martian regolith. And we used the receiver function (RF) method to explore the seismic structure of Martian regolith; this method is highly sensitive to velocity discontinuities beneath seismic stations (Lognonné et al., 2020). We calculated P-wave and PP-wave RF of this events in high frequency band, which contains information of regolith.</p> <p>In our results, we find that in addition to the three major seismic phases that had been detected by previous low-frequency events (Knapmeyer-Endrun et al., 2021), there is an obvious converted wave at around 1 seconds in both P-wave and PP-wave receiver functions.</p> <p> </p> <p>References</p> <p>InSight Mars SEIS Data Service. (2019). Seis raw data, insight mission. <em>Seis Raw Data, Insight Mission. IPGP, JPL, CNES, ETHZ, ICL, MPS, ISAE-Supaero, LPG, MFSC.</em> https://doi.org/10.18715/SEIS.INSIGHT.XB_2016</p> <p>Knapmeyer-Endrun, B., Panning, M. P., Bissig, F., Joshi, R., Khan, A., Kim, D., et al. (2021). Thickness and structure of the martian crust from InSight seismic data. <em>Science</em>, <em>373</em>(6553), 438–443. https://doi.org/10.1126/science.abf8966</p> <p>Lognonné, P., Banerdt, W. B., Pike, W. T., Giardini, D., Christensen, U., Garcia, R. F., et al. (2020). Constraints on the shallow elastic and anelastic structure of Mars from InSight seismic data. <em>Nature Geoscience</em>, <em>13</em>(3), 213–220. https://doi.org/10.1038/s41561-020-0536-y</p> <p>Yoldi, Z., Pommerol, A., Jost, B., Poch, O., Gouman, J., & Thomas, N. (2015). VIS-NIR reflectance of water ice/regolith analogue mixtures and implications for the detectability of ice mixed within planetary regoliths: VIS-NIR REFLECTANCE OF ICY MIXTURES. <em>Geophysical Research Letters</em>, <em>42</em>(15), 6205–6212. https://doi.org/10.1002/2015GL064780</p> <p>Zhang, T., Wang, B., Wei, H., Zhang, Y., Chao, C., Xu, K., et al. (2021). Review on planetary regolith-sampling technology. <em>Progress in Aerospace Sciences</em>, <em>127</em>, 100760. https://doi.org/10.1016/j.paerosci.2021.100760</p>