A consideration on intensity of odor in natural slopes and the release of odor at landslide disasters

摘要

The release of strong odor is known as a premonitory phenomenon of landslide disasters. The measurements of oder intensity in ground were carried out at the sites in Mt. Gagara in Hiroshima University and eight natural Masado slopes in Hiroshima Prefecture. At the five sites, the odor intensities were more than 100, and no odor was measured at 2 sites. The intensity of odor in the ground was related to the ignition loss of soil sample, suggesting that the existence of bacteria which resolves organic substance in the soil is a reason of the odor in ground. By the rainfall infiltration test of the model ground where the resource of odor was placed at the bottom, it was found that the rapid increase of odor intensity was observed at the ground surface when the ground water level elevated near the ground surface. The results show the possibility that the air with odor in ground is pushed out to the atmothphere by the elevation of ground water level due to the infiltration of rain.