Landslides are common features found on steep slopes on Mars and the role of water in their formation is an open question. Our study focuses on three young martian landslides whose mechanism of formation is unknown and knowing their formation mechanism could give us key information on recent martian climate and/or tectonics. They are less than 5 ​km long, and formed during the Late Amazonian Epoch, with an age <20 ​Ma when Mars is thought to have had a hyperarid climate. To better understand the dynamics and formation mechanism of these landslides, we combine two approaches: geomorphic comparison between martian and terrestrial landslides using remote sensing data from the High Resolution Imaging Science Experiment (HiRISE) and the Colour and Stereo Surface Imaging System (CaSSIS), and numerical modelling using a dry granular flow dynamical model. Our geomorphic analysis revealed two contrasting morphologies suggesting differing dynamics and formation mechanisms. Two of the three martian landslides resemble terrestrial rockslides, while the third is more akin to terrestrial mudslides. The numerical modelling, although not fully conclusive, broadly supports our interpretations from the morphological observations. We suggest that the two landslides resembling terrestrial rockslides could have been triggered by shaking by meteorite impact or marsquakes in the absence of water. On the contrary, we suggest liquid water (originating from ground-ice melted by geothermal heat flux) may have been involved in the initiation of the landslide resembling a terrestrial mudslide. Our results show the value of using morphological comparison between martian and terrestrial landslides combined with numerical modelling to inform the hypotheses of landslide-formation on Mars where in situ analysis is not usually possible.

滑坡是火星陡坡上常见的特征，水在其形成中的作用是一个悬而未决的问题。我们的研究侧重于三个年轻的火星滑坡，其形成机制尚不清楚，了解它们的形成机制可以为我们提供有关近期火星气候和/或构造的关键信息。它们长不到 5 公里，形成于亚马逊纪晚期，年龄 <20 Ma，当时人们认为火星的气候非常干旱。为了更好地了解这些滑坡的动力学和形成机制，我们结合了两种方法：使用高分辨率成像科学实验 (HiRISE) 和彩色和立体表面成像系统 (CaSSIS) 的遥感数据对火星和陆地滑坡进行地貌比较，和使用干颗粒流动动力学模型的数值模拟。我们的地貌分析揭示了两种截然不同的形态，表明不同的动力学和形成机制。三个火星滑坡中的两个类似于陆地滑坡，而第三个更类似于陆地泥石流。数值模型虽然不是完全决定性的，但广泛支持我们从形态学观察中得出的解释。我们认为，这两个类似陆地岩石滑坡的滑坡可能是由陨石撞击或在没有水的情况下地震引起的震动引发的。相反，我们认为液态水（源自地热热通量融化的地冰）可能参与了类似于陆地泥石流的滑坡的开始。