Abstract Almost all areas of the UK have been affected by periglaciation during the Quaternary and, as such, relict periglacial geohazards can provide a significant technical and commercial risk for many civil engineering projects. The processes and products associated with periglaciation in the relict periglacial landscape of the UK are described in terms of their nature and distribution, the hazards they pose to engineering projects, and how they might be monitored and mitigated. A periglacial landsystems classification is applied here to show its application to the assessment of ground engineering hazards within upland and lowland periglacial geomorphological terrains. Techniques for the early identification of the susceptibility of a site to periglacial geohazards are discussed. These include the increased availability of high-resolution aerial imagery such as Google Earth, which has proved to be a valuable tool in periglacial geohazard identification when considered in conjunction with the more usual sources of desk study information such as geological, geomorphological and topographical publications. Descriptions of periglacial geohazards and how they might impact engineering works are presented, along with suggestions for possible monitoring and remediation strategies.

Abstract The Hale impact crater is a large complex crater ( c. 150 × c. 125 km) in the southern hemisphere of Mars. Recurring slope lineae have been observed on its central-peak slopes, as have relatively youthful gully-like landforms; the latter are observed adjacent to or in the midst of the former, as well as on all of the rim-material slopes. Three of the gullied slopes on the northern-rim materials exhibit landscape features that, on Earth, are synonymous with wet periglaciation, i.e. landscape modification by the freeze–thaw cycling of water. These features include: (1) gelifluction-like lobes; (2) patches of surface polygonization, possibly underlain by ice wedges and formed by thermal-contraction cracking; and (3) shallow, rimless and polygonized basins morphologically akin to terrestrial alases. Here, we use the spatial association of the gully-like landforms together with the putatively wet periglacial assemblages or complexes to deduce and ascribe, albeit indirectly, a wet origin to the former.

We present landforms on Svalbard (Norway) as terrestrial analogs for possible Martian periglacial surface features. While there are closer climatic analogs for Mars, e.g., the Antarctic Dry Valleys, Svalbard has unique advantages that make it a very useful study area. Svalbard is easily accessible and offers a periglacial landscape where many different landforms can be encountered in close spatial proximity. These landforms include thermal contraction cracks, slope stripes, rock glaciers, protalus ramparts, and pingos, all of which have close morphological analogs on Mars. The combination of remote-sensing data, in particular images and digital elevation models, with field work is a promising approach in analog studies and facilitates acquisition of first-hand experience with permafrost environments. Based on the morphological ambiguity of certain landforms such as pingos, we recommend that Martian cold-climate landforms should not be investigated in isolation, but as part of a landscape system in a geological context.