It is important to accumulate research examples on the spatial distribution of dikes under volcanic edifices for risk assessment in volcanic disaster prevention and site selection and safety assessment for the geological disposal of high- level radioactive waste. The topography of volcanoes is considered to represent the location of magma intrusion associated with volcanic activity and its history. In this study, we attempted to determine the predominant orientation of radial dikes and evaluate the central conduit stability based on the distribution, centroid, and area of contour lines comprising the volcanic edifices using GIS-based topographic analysis. As a result of the topographic analysis, the predominant orientation of the dikes was successfully shown for the volcanoes with stable conduits. On the other hand, this analysis was not suitable for determine the predominant orientation of dikes in volcanoes with unstable conduits, thus the applicable range of this analysis is considered to be determined by the conduit stability. In addition, the conduit stability can be evaluated by using the area data of contour polygons, which represents the scope of application to the method for determination of the predominant orientation of dikes. This means that the conduit stability during volcanic activity can be evaluated even for volcanoes of which activity history is not yet known, and that topographic analysis is a useful tool for this purpose. The use of topographic analysis in this study will be expected to provide a new scale for the history of volcanic activity.

Mercury, which can be measured in very small amounts, is highly volatile under high temperature conditions deep underground and migrates to form a mercury dispersion halo at the surface. The mercury survey covers soil mercury content（mercury and mercury compounds in the liquid and solid phases）and mercury vapor content（mercury in the gas phase）. The relationship between mercury in the liquid phase of soil and mercury vapor concentration is reported to be a temperature-dependent Henry's law vapor-liquid equilibrium.

In creating a mercury dispersion halo map, it was necessary to consider factors that cause variation in mercury vapor concentrations, and it was reported that, in addition to temperature and sunlight, the concentration of mercury vapor on the ground surface increases when the soil is moistened by rainfall after drying.

However, previous studies have not taken into account the volatilization of mercury during the drying and wetting processes of the soil when creating mercury dispersion halo maps. Measurements taken after rainfall in the field yielded results averaging 18 times greater when dry. The effect of watering after drying was found to be extremely significant. Based on these results, laboratory tests were conducted to determine how mercury fluctuates with water after drying. This paper reports the results and discussion of these indoor and outdoor tests.

We hope that this method will be reevaluated as mercury exploration methods become more sophisticated.

The time-series changes in landslide micro-topography type were studied and confirmed based on aerial photograph interpretation using six periods of large-scale landslides，mass movement landforms in mountainous areas. The aerial photographs used in this study were taken in 1947, 1957, 1974, 1983, 2004, 2014，respectively. Landslide topography was extracted using the Red Relief Image Map created from 5 m DEM. A “landslide block activity transition status map” was created as an applied geomorphological map, in which the activity status of each micro-topography type was estimated over a time scale of about 70 years. The new appearance of each micro-topography type was extracted by aerial photograph interpretation, and the new appearance of ground surfaces, small landslide blocks, collapsed areas, cracks, etc. were compared and analyzed with aerial photographs taken during the previous period. This method was confirmed to be effective in tracing the onset of localized displacement such as slow movement and toe area of large-scale landslides. In further study, it is necessary to increase the number of applications of this method by combining the use of DEM from LiDAR with multi-temporal aerial photograph interpretation for various micro-topography types of mass movement landforms, and a legend for applied geomorphological map is need to be created.