Autocorrelation R₂ on Mars

Abstract

The InSight (Interior Exploration Using Seismic Investigations, Geodesy and Heat Transport) spacecraft landed on Mars on 26 November 2018 and installed the seismograph SEIS (Seismic Experiment for Interior Structure) (Lognonné et al., 2019) to record continuous seismic data for approximately 3 years, providing opportunities to investigate another terrestrial planet's interior. A variety of research studies have been conducted recently to analyze the seismic recordings on Mars to monitor the seismicity (

Global Crustal Thickness Revealed by Surface Waves Orbiting Mars

“…Such abruptness in dispersion and the observed low and high velocities from the R2–R7 signals (Figure S3 in Supporting Information ) cannot be solely attributed to elliptically polarized martian wind (e.g., Stutzmann et al., 2021) contaminating the data which is unlikely to be recorded with the apparent periodicity for both LP and VLP data. At much longer periods between 100 and 200 s, a similar group velocity close to 3.8 km/s for the excitation of R2 has been reported by using ambient noise correlations (Deng & Levander, 2022). A normal mode study on Mars has also shown some potential excitation of the fundamental mode surface waves in comparable period ranges between 120 and 300 s (Lognonné et al., 2023).…”

Seismic Autocorrelation Analysis of Deep Mars

“…(2021) best matches the timing of the observed PcP phase. This observation is consistent with the Mars orbiting surface wave results retrieved from ambient noise autocorrelation (Deng & Levander, 2022). We will use Stähler et al.…”

“…Timing of the PcP phase (∼385 s) is best matched using Stähler et al. (2021)'s mean‐3σ model (Figure 3b), consistent with Mars orbiting surface wave R2 results (Deng & Levander, 2022). We then calculated synthetic PcP phases for a velocity transition zone at the CMB in which we varied velocity and layer thickness to model the observed complexity of the PcP waveform (Figure 4).…”

“…The comparison between synthetic and real PcP signals (Figure 3b) shows that the velocity model 3 standard deviations lower than the mean model of Stähler et al (2021) best matches the timing of the observed PcP phase. This observation is consistent with the Mars orbiting surface wave results retrieved from ambient noise autocorrelation (Deng & Levander, 2022). We will use Stähler et al ( 2021)'s mean-3σ model (Figure 3a) as a reference in later analysis.…”

“…The InSight seismometer successfully detected ∼1,300 Marsquake events before its termination in December 2022 (Ceylan et al., 2023), providing indications of Martian tectonic activity (Ceylan et al., 2022; Drilleau et al., 2022; Giardini et al., 2020; Horleston et al., 2022; Jacob et al., 2022; Sun & Tkalčić, 2022). These seismic data have been used to determine the interior structures of the red planet at different scales using surface wave analysis (Beghein et al., 2022; Deng & Levander, 2022; Kim et al., 2022; Li et al., 2023; Xu et al., 2023), autocorrelation functions (ACFs) (Compaire et al., 2021; Deng & Levander, 2020, 2022; Qin et al., 2023; Schimmel et al., 2021), receiver functions (Knapmeyer‐Endrun et al., 2021; Lognonné et al., 2020), anisotropy analysis (Li et al., 2022), attenuation modeling (Karakostas et al., 2021) and geophysical inversion (Khan et al., 2021; Stähler et al., 2021). Lognonné, Banerdt, et al.…”