NH9.11Why natural hazard assessment and mitigation sometimes fail and how to improve them
|Convener: Antonella Peresan | Co-Convener: Seth Stein|
The dramatic images of the tsunami that struck Japan's Tohoku coast in March 2011 catalyzed a growing realization among scientists interested in natural hazards that present approaches often prove inadequate. The earthquake and resulting tsunami were much larger than predicted by sophisticated hazard models, and expensive hazard mitigation measures failed. This failure was the latest in a series indicating the limitations of current natural hazards methodology. A number of devastating earthquakes have occurred in areas predicted by hazard maps to be relatively safe. Hurricane Katrina flooded much of New Orleans, despite extensive defensive measures. Major damage from river flooding has occurred in many countries. Thus in its high-stakes game against nature, society is often not doing well.
The session aims to promote discussion of methods and experiences in natural hazard assessment, modeling, communication, and mitigation, with the goal of improving them. For example, the recent failures bear out the surprising fact that although earthquake hazard maps are widely used in many countries, their results have never been objectively tested. Hence understanding, quantifying, and communicating their uncertainties is necessary for their improvement and effective implementation. Developing strategies for rare but potentially very destructive events is another major challenge. For example, what mitigation strategies make sense for areas prone to mega-tsunamis in areas like Japan, given that the timescale on which such events may occur is unknown and likely to be of order 1000 years?
The session will provide the opportunity to illustrate results, assess the status and limits of current methodologies and the available alternatives, and explore approaches for further development. Contributions on topics including the following are expected:
- Issues and challenges in seismic, tsunami, and other natural hazard assessment and mitigation;
- Theoretical issues and development of testing strategies;
- Tools for assessment and validation of models;
- Lessons learnt from recent disasters and their application to models' revision and improvement;
- Development of cost-effective mitigation strategies.