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In the case of the volcanic eruption of Mount Usu in 2000, there were no victims because the evacuation activities were carried out smoothly, as people made great use of the hazard map of Usu Volcano as a source of information. Also, the Mount Fuji Hazard Map Committee started work in 2001, scheduled to publicize the results in the near future. Although volcanic hazard maps have only recently captured the attention to people in Japan, they have been used in various overseas countries for many years. This paper summarizes the definition of volcanic hazard maps and the method of making volcanic hazard maps, classifies and analyzes the collected foreign cases, and introduces representative examples.

This paper reports a method to make hazard maps of sediment disasters resulting from an earthquake and following heavy rainfall for the entire region of Gunma prefecture, Japan. Firstly, we identified the slopes in the study area, which are susceptible to large-scale landslides and land failures during an earthquake with a magnitude of seven on the Richter scale. To analyze the sheer volume of the data, we employed a statistical method to evaluate the susceptibility, mainly considering geomorphologic conditions. Secondly, we extracted mudflow and slope failure susceptible areas and potential flooding zones resulting from a damming at a river triggered by the earthquake and heavy rainfall, and we identified the settlements which would be isolated by the road disruption caused by the sediment disasters. As the result, 359 settlements were classified as potential isolation areas. Combining the above-mentioned susceptibility maps, we obtained two types of sediment disaster hazard maps of the study area, depicting the potential hazards which would occur during the earthquake and the disasters which would be caused by heavy rainfall following the quake, respectively. These hazard maps and the disaster information would be useful for the regional disaster prevention planning and countermeasures in the future.

The large earthquake with Ms 7.7 struck central Taiwan on Sep. 21, 1999, and had ten times as much seismic energy as 1995 Hyogo-ken Nanbu Earthquake. Nantou and Taichung County near the epicenter were most badly hit by the earthquake, and in all Taiwan 2,321 people were killed and more than 52,000 buildings were collapsed or damaged till Oct. 11, 1999. We investigated the disaster area one month after the earthquake had occurred. This report outlines the result of the investigation, and especially describes the relationship between soil and the damage to city facilities, and between earthquake surface fault and the damage to civil engineering structures.