Knowledge of lithospheric strength can help to understand the internal structure and evolution of the terrestrial planets, as surface topography and gravity fields are controlled mainly by deformational features within the lithosphere. Here, strength profiles of lithosphere were calculated for each planet using a recently updated flow law and taking into account the effect of water on lithospheric deformation. Strength is controlled predominantly by brittle deformation at shallow depths, whereas plastic deformation becomes dominant at greater depths through its sensitivity to temperature. Incorporation of Peierls creep, in which strain rate is exponentially dependent on stress, results in the weakening of plastic strength at higher stress levels, and the transition from brittle to ductile deformation shifts to shallower depths than those calculated using conventional power-law creep. Strength in both the brittle and ductile regimes is highly sensitive to the presence of water, with the overall strength of the lithosphere decreasing markedly under wet conditions. The markedly low frictional coefficient of clay minerals results in a further decrease in brittle strength and is attributed to expansion of the brittle field. As plastic strength is influenced by lithology, a large strength contrast can occur across the crust–mantle boundary if deformation is controlled by ductile deformation. Effective elastic thickness for the terrestrial planets calculated from the rheological models indicates its close dependence on spatiotemporal variations in temperature and the presence of water. Although application of the strength models to observed large-scale surface deformational features is subject to large extrapolation and uncertainties, I emphasize the different sensitivity of these features to temperature and water, meaning that quantifying these features (e.g., by data from orbiting satellites or rovers) should help to constrain the internal structure and evolution of the terrestrial planets.

由于表面形貌和重力场主要由岩石圈内部的变形特征控制，因此了解岩石圈强度可以帮助您了解地球行星的内部结构和演化。在这里，使用最新更新的流量定律并考虑到水对岩石圈变形的影响，计算了每个行星的岩石圈强度分布。强度主要由浅深度的脆性变形控制，而塑性变形由于其对温度的敏感性而在较大深度变得占主导。Peierls蠕变的引入（应变速率与应力成指数关系）导致较高应力水平下的塑性强度减弱，从脆性到延性变形的过渡比使用常规幂律蠕变计算的深度要浅。脆性和延性两种状态下的强度对水的存在高度敏感，在潮湿条件下岩石圈的整体强度显着下降。粘土矿物的明显较低的摩擦系数导致脆性强度进一步降低，并且归因于脆性场的扩展。由于塑性强度受岩性的影响，如果变形是由延性变形控制的，则整个地壳—地幔边界会发生较大的强度对比。根据流变模型计算得出的地球行星的有效弹性厚度表明，它与温度和水的时空变化密切相关。