Marsquake Locations and 1‐D Seismic Models for Mars From InSight Data

Abstract

With 100s of seismic events detected since the deployment of the first seismometer at the surface of Mars (Clinton et al., 2021;Giardini et al., 2020), the Seismic Experiment for Interior Structure (SEIS) of Mars (Lognonné et al., 2019) from the InSight (Interior Exploration using Seismic Investigations, Geodesy and Heat Transport) mission has shown that the red planet is seismically active. The estimated global seismic event rate indicates a moderately active planet, with a value far above that of the Moon (excluding deep moonquakes associated with tidal stresses) and slightly below that of the Earth, based on intraplate earthquakes (Banerdt et al., 2020). Most of

Largest recent impact craters on Mars: Orbital imaging and surface seismic co-investigation

“…The close agreement between distance estimates and the imaged locations increases our confidence in the martian seismic velocity models ( 44 – 48 ) for the regions sampled by the direct body waves (fig. S10).…”

“…This mismatch implies that either the P velocities at the CMB need adjustment, or the V P / V S ratio in the lower mantle is different from current predictions. These two events act as calibrated measurements and help select among various martian interior seismic velocity models ( 44 – 48 ); they corroborate Mars mantle velocity models to 800 km depth and will help to improve future models down to the CMB.…”

Constraints on the martian crust away from the InSight landing site

“…After the successful touchdown of the InSight lander 1 , the subsequent detection of marsquakes 2 , and the initial inference of the shallow crustal structure 3 , a family of 94 low-frequency marsquakes 4 , 5 have been detected and recorded by the Seismic Experiment for Interior Structure (SEIS) seismometer 6 . In the first two and a half years, all the marsquakes with known epicentral distances occurred within a distance of fewer than 100 degrees 7 , 8 , and most of those with known back azimuths clustered at epicentral distances around 30 degrees (i.e., about 1700 km) to the east of the InSight landing site 9 , 10 , near Cerberus Fossae (Fig. 1a ).…”

A Positive Feedback Between Crustal Thickness and Melt Extraction for the Origin of the Martian Dichotomy

“…The rather cold potential temperature is in line with the EarlyDich case (Figure 6d). Drilleau et al (2022) also used an inversion of the arrival time data with geodynamic constraints and found similar lid thicknesses but with a somewhat warmer potential mantle temperature of 1,830 ± 60 K which is in better agreement with the LateDich scenario. However, the compositional model of Drilleau et al (2022) is less enriched in HPEs than the one we consider in this study which favors higher initial and hence final temperatures.…”

“…Drilleau et al (2022) also used an inversion of the arrival time data with geodynamic constraints and found similar lid thicknesses but with a somewhat warmer potential mantle temperature of 1,830 ± 60 K which is in better agreement with the LateDich scenario. However, the compositional model of Drilleau et al (2022) is less enriched in HPEs than the one we consider in this study which favors higher initial and hence final temperatures. The detection of the postolivine phase transition at depth provides additional constraints on the thermal state and chemistry of the Martian mantle which also points to a rather cold mantle at the present-day with T p = 1,605 ± 100 K (Huang et al, 2022).…”