Seismic Noise Autocorrelations on Mars. Issue 6 (22nd June 2021)

• Record Type: Journal Article
• Authors: Schimmel, Martin; Stutzmann, Eleonore; Lognonné, Philippe; Compaire, Nicolas; Davis, Paul; Drilleau, Melanie; Garcia, Raphael; Kim, Doyeon; Knapmeyer‐Endrun, Brigitte; Lekic, Vedran; Margerin, Ludovic; Panning, Mark; Schmerr, Nicholas; Scholz, John Robert; Spiga, Aymeric; Tauzin, Benoit; Banerdt, Bruce
• Is Part Of: Earth and space science. Volume 8:Issue 6(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-06-22
• Subjects: Space sciences -- Periodicals; Geophysics -- Periodicals; 500.5
• DOI: 10.1029/2021EA001755
• Languages: English
• ISSNs: 2333-5084

Abstract

Abstract: Mars is the first extraterrestrial planet with seismometers (Seismic Experiment for Interior Structure, SEIS) deployed directly on its surface in the framework of the Interior Exploration using Seismic Investigations, Geodesy and Heat Transport (InSight) mission. The lack of strong Marsquakes, however, strengthens the need of seismic noise studies to additionally constrain the Martian structure. Seismic noise autocorrelations of single‐station recordings permit the determination of the zero‐offset reflection response underneath SEIS. We present a new autocorrelation study which employs state‐of‐the‐art approaches to determine a robust reflection response by avoiding bias from aseismic signals which are recorded together with seismic waves due to unfavorable deployment and environmental conditions. Data selection and segmentation is performed in a data‐adaptive manner which takes the data root‐mean‐square amplitude variability into account. We further use the amplitude‐unbiased phase cross‐correlation and work in the 1.2–8.9 Hz frequency band. The main target are crustal scale reflections, their robustness and convergence. The strongest signal appears at 10.6 s, and, if interpreted as a P ‐wave reflection, would correspond to a discontinuity at about 21 km depth. This signal is a likely candidate for a reflection from the base of the Martian crust due to its strength, polarity, and stability. Additionally we identify, among the stable signals, a signal at about 6.15 s that can be interpreted as the P ‐wave reflection from the mid‐crust at about 9.5 km depth. Key Points: Estimation of high‐frequency reflection response using phase autocorrelations of seismic noise recorded on Mars at the InSight landing site Presentation of a new data processing method that avoids aseismic signal bias and stability analysis of the reflection response A signal at 10.6 s lag time is a possible candidate for a reflection from the base of the crust due to its strength, polarity, and stability