Crustal Structure Constraints From the Detection of the SsPp Phase on Mars

The shallowest intracrustal layer (extending to 8 ± 2 km depth) beneath the Mars InSight Lander site exhibits low seismic wave velocity, which is likely related a combination of high porosity and other lithological factors. SsPp phase, an SV- P-wave reflection on receiver side, naturally suited for constraining structure this top crustal since its prominent signal makes it observable with single station without need stacking. We have analyzed six broadband low-frequency events recorded made first coherent detection phase red planet. timing amplitude confirm existence ?8 interface in crust large speed (or impedance) contrast across it. With our new constraints from we determined that average between 2.5 3.2 km/s, more precise robust estimate than previous range 2.0–3.5 km/s obtained by function analysis. velocity Layer 1 results presence relatively low-density lithified sedimentary rocks and/or aqueously altered igneous also significant amount porosity, possibly as much 22%–30% volume (assuming aspect ratio 0.1 pore space). These porosities speeds are compatible current understanding upper stratigraphy site.