Disaster Reduction Measures Research Articles

Damage and casualties modelling as part of a vulnerability assessment for tsunami hazards: a case study from Aceh, Indonesia

AbstractVulnerability reduction to tsunamis has become a major issue after the December 2004 Indian Ocean tsunami disaster. An ex ante (before the event) evaluation of possible disaster reduction measures requires insight into the potential risks. As part of a study focusing on sea defence measures for Aceh and Nias provinces in Indonesia, we have developed a model that is capable of quantifying potential damages and casualties for tsunami‐prone coastal areas. The model was able to reproduce the damage of 2004 sustained in Banda Aceh quite accurately. Because it is GIS based, the model also shows the spatial distribution of damage. Maps can be prepared that show high‐ and low‐impact areas for various tsunami event scenarios. This information is very useful for cost–benefit analysis of mitigation measures, such as sea defence measures, spatial planning and evacuation procedures.

活断層情報を考慮した防災対策と住民の意識構造

Active fault information has been more widely and closely researched, and extensive data have been collected. With the progress, earthquake disaster reduction measures based on active fault information should be examined. The purpose of this paper is to arrange disaster reduction measure cases that have been considered with active fault information, and to indicate problems and directions to promote disaster reduction measures based on a questionnaire survey. Disaster reduction measures based on active fault information are distinguished into three types : building restrictions, non-building restrictions, and risk communication. The questionnaire survey was carried out with residents of Yokosuka city. The questionnaire items concerned the recognition and perception of regional earthquake risk, the perception of general earthquake risk, the awareness of general disaster reduction measures, and the awareness of disaster reduction measures based on active fault information. The results show that there are also three factors in the perceptions of residents, which are building restrictions, non-building restrictions, and risk communication, and their measures may be implemented with the recognition of residents on the need for land use controls based on active fault information. Other analysis results indicate that earthquake risk perception is high, but there are no significant correlations between individual earthquake risk perceptions and the awareness of disaster reduction measures. To promote disaster reduction measures based on active fault information and earthquake risk, it is important that such awareness is connected.

首都直下地震に備える事前復興の取り組み―東京における震災復興対策と復興訓練から―

Considering the immense scale of damage caused by the next Tokyo Earthquake, occurring beneath a mega-city that is the capital of Japan, a quick response requires pre-disaster measures and post-disaster recovery planning to mitigate economic losses and damage to central functions. Tokyo Metropolitan Government (TMG) learned from the Great Hanshin-awaji Earthquake of 1995, and has prepared such recovery measures.Because a huge amount of damage is expected on a scale approximately ten times as great as that caused by the Great Hanshin-awaji Earthquake, restoration from the next Tokyo Earthquake cannot be completed without the participation of citizens and enterprises. In particular, it is important for the recovery of damaged districts to be implemented through community power. Accordingly, TMG published the “Planning Manual for Post-Disaster Urban Restoration Planning” in 1997, and “Administrative Manual for Post-Disaster recovery Measures for Living” in 1998. At the same time, a new type of drill for urban recovery after an earthquake, rather than disaster response activities, was developed by TMG and Tokyo Metropolitan University.This paper summarizes pre-disaster measures for post-disaster recovery planning prepared. by TMG. Two drill programs are introduced : (1) community restoration drill program for citizens and (2) administrative staff training for post-disaster urban reconstruction planning. Finally, the positioning and roles of these two programs among disaster reduction measures are discussed.

首都直下地震の被害想定と対策

The Central Disaster Management Council conducted damage estimation research on the next Tokyo Metropolitan Earthquake. The estimation clarified that the earthquake would bring not only a huge amount of physical damage, but also serious influence on the metropolitan functions such as politics, administration, and economy. The “Policy Framework for Tokyo Metropolitan Earthquakes” was set to secure the continuity of metropolitan functions as well to reduce damage. The “Tokyo Metropolitan Earthquake Disaster Reduction Strategy” was also shown by setting quantitative disaster reduction objectives with definite deadlines and concrete plans to execute disaster reduction measures effectively and properly. Furthermore, the “Guidelines for Tokyo Metropolitan Earthquakes Emergency Response Plan”, which provides the contents of emergency activities in a large area, and procedures and roles of government in the event of a disaster, was regulated. Measures for evacuees and people stranded without bearable means of returning to their homes, and contingency plans for central governments are under discussion.

Managing Debris Flow Risks

Debris flows represent a widespread threat to villages and small towns in the Swiss Alps. For many centuries people “managed” such risks by trying to avoid hazardous areas. However, major debris flow and flood events in the last 25 years have revealed that the degree of freedom to engage in this type of risk management has substantially decreased. This became especially evident during the 1999 disasters in a number of places in Switzerland. The winter of that year was unusually wet. In February heavy snowfall triggered destructive avalanches. In May high temperatures caused heavy snowmelt, with excessive rainfall contributing more water to the already saturated soils. Landslides, debris flows and floods were triggered in many locations, including Sörenberg. Hazard prevention and disaster management have a long tradition in Switzerland, although an integrated approach to risk management is rather new. Only in recent years have methods and tools been developed to assess hazards, define protection goals, and implement disaster reduction measures. The case of Sörenberg serves as an example of how today's approaches to disaster reduction are implemented at the local level.

Dynamic Evaluation Model for Large Earthquake Disaster

From national to local governments and private sectors, many organizations have carried out earthquakes damage estimation of their facilities by comparing their strength and earthquake demand. Based on these estimations, they have established plans for disaster reduction measures. Although these earthquake damage estimations are conducted by consuming large budgets and time, in many cases the results are neither used well nor trusted, especially by specialists. Why?The major reason is that these estimation results are calculated based upon chains of assumptions. In other words, the probability of having the assumptions adopted in the damage estimation calculation is very low. Furthermore, simulations are carried out under static conditions while real phenomenon is very dynamic.Although a static condition is used in many simulations, the time factor is certainly very important, especially for human related activities. For a reliable assessment of earthquake disaster damage, three time factors must be considered. The first defines the characteristics of the social system and development level of the affected area. The second is related to the point in time when the event occurs : season, month, day, hour, etc. The last is time elapsed after the event.Recently, accurate estimations of the characteristics of an earthquake (location, magnitude, mechanism, etc.) and the strong ground motion at each site is improving. However, even if accuracy becomes reliable, damage caused by the event cannot be discussed quantitatively as there is great uncertainty due to time factors and research on how to manage this uncertainty is scarce.In this paper, the direction of future research on earthquake damage evaluation and disaster countermeasure plans are discussed stressing the above-mentioned issues. Some studies on these matters are introduced.

Vibration-Isolation Retrofit for the National Museum of Western Art, Tokyo

The National Museum of Western Art in Tokyo, designed by Le Corbusier, is highly valued, not least because it is the only building by the renowned architect in East Asia. The museum, opened in 1959, is currently being completely renovated and expanded, and the main building has also been reinforced against earthquakes as part of a program of disaster-reduction measures. Comprehensive studies of earthquake-resistant reinforcement, building preservation and effective building utilization were carried out for this project.