A planet’s crust bears witness to the history of planetary formation and evolution, but for Mars, no absolute measurement of crustal thickness has been available. Here, we determine the structure of the crust beneath the InSight landing site on Mars using both marsquake recordings and the ambient wavefield. By analyzing seismic phases that are reflected and converted at subsurface interfaces, we find that the observations are consistent with models with at least two and possibly three interfaces. If the second interface is the boundary of the crust, the thickness is 20 ± 5 kilometers, whereas if the third interface is the boundary, the thickness is 39 ± 8 kilometers. Global maps of gravity and topography allow extrapolation of this point measurement to the whole planet, showing that the average thickness of the martian crust lies between 24 and 72 kilometers. Independent bulk composition and geodynamic constraints show that the thicker model is consistent with the abundances of crustal heat-producing elements observed for the shallow surface, whereas the thinner model requires greater concentration at depth.

行星的地壳见证了行星形成和演化的历史，但对于火星，没有绝对的地壳厚度测量方法。在这里，我们使用地震记录和环境波场来确定火星上洞察号着陆点下方的地壳结构。通过分析在地下界面反射和转换的地震相位，我们发现观测与具有至少两个甚至可能三个界面的模型一致。如果第二界面为地壳边界，则厚度为 20±5 公里，而如果第三界面为边界，则厚度为 39±8 公里。全球重力和地形图允许将此点测量外推到整个星球，表明火星地壳的平均厚度在 24 到 72 公里之间。独立的整体成分和地球动力学约束表明，较厚的模型与在浅表层观察到的地壳发热元素的丰度一致，而较薄的模型需要在深处有更大的浓度。