Earth’s surface is composed of a staggering diversity of particulate–fluid mixtures: dry to wet, dilute to dense, colloidal to granular and attractive to repulsive particles. This material variety is matched by the range of relevant stresses and strain rates, from laminar to turbulent flows and steady to intermittent forcing, leading to anything from rapid and catastrophic landslides to the slow relaxation of soil and rocks over geologic timescales. From a physics point of view, virtually all Earth and planetary landscapes are composed of soft matter, in the sense that they are both deformable and sensitive to collective effects. Geophysical materials, however, often involve compositions and flow geometries that have not yet been examined in physics. In this Review, we explore how a soft-matter physics perspective has helped to illuminate, and even predict, the rich dynamics of earth materials and their associated landscapes. We also highlight phenomena of geophysical flows that challenge, and will hopefully inspire, work on more fundamental aspects of soft matter.

地球表面由各种不同的颗粒-流体混合物组成：干到湿，稀到致密，胶体到颗粒，以及排斥颗粒。这种材料的种类与相关的应力和应变率范围相匹配，从层流到湍流，从稳定到间歇性强迫，导致在地质时标范围内，从快速的灾难性滑坡到土壤和岩石的缓慢松弛，无所不包。从物理学的角度来看，实际上，所有地球和行星景观都是由软物质组成的，因为它们既可变形又对集体效应敏感。但是，地球物理材料通常涉及尚未在物理学中进行检查的成分和流动几何形状。在本评论中，我们探讨了软物质物理学的观点如何帮助阐明，甚至可以预测地球材料及其相关景观的丰富动态。我们还将重点介绍挑战地球物理流的现象，并有望激发他们在软物质的更基本方面开展工作。