Ice and other mineral cements in Mars' shallow subsurface affect the mechanical properties of the shallow crust, the geologic processes that shape the planet's surface, and the search for past or extant Martian life. Cements increase seismic velocities. We use rock physics models to infer cement properties from seismic velocities. Model results confirm that the upper 300 m of Mars beneath InSight is most likely composed of sediments and fractured basalts. Grains within sediment layers are unlikely to be cemented by ice or other mineral cements. Hence, any existing cements are nodular or formed away from grain contacts. Fractures within the basalt layers could be filled with gas, 2% mineral cement and 98% gas, and no more than 20% ice. Thus, no ice- or liquid water-saturated layers likely exist within the upper 300 m beneath InSight. Any past cement at grain contacts has likely been broken by impacts or marsquakes.

中文翻译：

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洞察力之下的最低程度胶结的浅地壳

火星浅层地下的冰和其他矿物胶结物会影响浅层地壳的机械特性、塑造行星表面的地质过程，以及寻找过去或现存的火星生命。水泥增加地震速度。我们使用岩石物理模型从地震速度推断水泥性质。模型结果证实，洞察号下方的火星上层 300 m 很可能由沉积物和断裂的玄武岩组成。沉积层内的颗粒不太可能被冰或其他矿物胶结物胶结。因此，任何现有的胶结物都是结节状的或远离颗粒接触而形成的。玄武岩层内的裂缝可以充满气体、2% 的矿物水泥和 98% 的气体，以及不超过 20% 的冰。因此，在 InSight 下方 300 m 内可能不存在冰或液态水饱和层。