In recent years, the Great Acceleration of the Earth’s environment due to human activities has become apparent, and it has been pointed out that the Anthropocene has begun. It has not been established as a stratigraphic era, but as a broad cultural concept. The effects of human activities on landforms, such as man-made modification and sediment discharge due to vegetation clearance, have been widely recognized since the 1960s. Landforms and their classification have a significant bearing on human social life, including disaster prevention, urban development and planning, and land use. In Japan, the socioeconomic conditions surrounding the national land are changing drastically due to the combination of population decline and increased risk of natural disasters such as heavy rainfall due to climate change, and it is recognized as a turning point of the times. This paper discusses the functions required of geomorphological maps unique to the anthropogenic landforms, the elements needed, and the map scale, based on a survey of existing articles. In some urban areas in Japan, it has been reported that population decline has resulted in a tendency to cluster more in central areas, and for most watersheds, the population distribution within the watershed is shifting in a dangerous direction with respect to flooding. In response to the frequent occurrence of heavy rainfalls in recent years, pre-disaster mitigations are being made in various fields, and the direction is toward not building huge levees. Therefore, understanding land conditions, including man-made landforms, is expected to become important again in the future. The ideal functions, elements, and scale for the map are as follows: it should be a general-purpose GIS data package; it should be usable as a zoning map with an organized legend for natural as well as man-made landforms; it should be classified consistent with terrain geometric signature and borehole data; it should have time series information; it should have information useful for understanding the water environment; and the scale should be large enough to match human activities.

We collected high resolution bathymetric data and sediment samples at off the coast of Suzu, the Northeast of Noto peninsula, central Japan before the 2024 Noto Hanto Earthquake. Using multibeam-echo-sounding equipment, we updated the bathymetric imagery of the area with high resolution and compared slope failures with those in previous studies. The obtained imagery, however, reveals that there is no evidence of large-scale collapses as suggested by the previous studies, and many small-scale failures are found at the south slope. Previous studies in this region indicated that the wet density of sediments ranges 1.3-1.5 g/cm³ and it tends to decrease from the shelf to the ocean basin. Our sampling data show 1.47 g/cm³ and the decreasing curve is consistent with previous studies. In order to discuss the sediment transportation processes, we analyzed constituent minerals and foraminifera. Based on these data, sediments are continuously transported from inland through the upper part of the continental shelf slope to the oceanic basin by persistent and weak bottom currents rather than by sporadic and strong currents caused by large earthquakes and typhoons which can generate a turbidite layer.

LiDAR technology involves the use of lasers to measure the distances to objects with varying ranges and resolutions based on the environment. LiDAR-SLAM enables simultaneous self-positioning and mapping, so high-density point clouds can be acquired without relying on the GNSS. Low-cost MLSs are being increasingly adopted in engineering and automated driving owing to their affordability. However, studies on natural environment measurements are limited. As such, the aim in this study aimed was to summarize the methods of and challenges with implementing low-cost MLS for forest floor topographic surveying and to verify the optimal operating conditions. The results showed that with low- cost MLS using LiDAR-SLAM, the density of point cloud decreased with increasing irradiation distance, and became below the measurement limit in the case of more than 200 m, because of the measurement principle of SLAM and the influences of and the environment. The point cloud density varied depending on the object, particularly under wet conditions. The key finding was that the characteristics of low-cost MLSs and the SLAM drift phenomenon must be taken into account because the optimal measurement modes depend on vegetation cover and surface humidity, requiring ingenuity for measurements of obstructed environments such as the forest floor.