FLOOD03837 - Laserfiche WebLink

Home Browse Search

38 minutes of major offshore earthquake events. The Chilean Standard Operations Procedure Manual for tsunami warning and evacuation is a model for other threatened nations. A program ro reduce tsunami losses would, certainly, include development of global forecast- ing of tsunami dangers and the evaluation and mitigation of coastal tsunami hazards. During the IDNHR, a significant effort should be made ro gather field data related to the generation and propagation of a tsunami. For example, instru- ments could be deployed in a region off the Alaska Peninsula, where the probability of a tsunami- causing earthquake is high. Instruments could also be deployed in distant nearshore regions. Such a program would help refine predictive capabilities with regard ro timing and the destruc- tive potential of a wave. For evaluation of coastal tsunami hazards, the probability of occurrence, the maximum limits of inundation, and maximum forces that can be exerted on stationary and moveable objects must be determined. Such information can provide land use guidelines and engineering design criteria for potentially threatened areas and could become the baseline for reducing life and property loss. Potential projects during the IDNHR include: ~ open ocean measurement of tsunamis coupled with earthquake measurements to obtain field data on tsunami generation and propagation; . a program for nearshore measurement of tsunamis and their run-up, with instrumentation of selected sites around the Pacific that historically have been affected by tsunamis; ~ development and implementation of numer- ical models ro be incorporated in warning systems to provide real-time tsunami inundation esti- mates; ~ confirmation of numerical models with large- scale hydraulic models; and . structuring of international teams for rapid response ro investigate tsunami events quickly before evidence of run-up and damage is obliter- ated. WINDSTORMS Windstorm-related events worldwide cause an average of 30,000 deaths and $2.3 billion in damage each year, Severe tropical srorms (called hurricanes in the Atlantic, Caribbean, and eastern Pacific; typhoons in the western Pacific; and cyclones in the Indian Ocean), tornadoes, bliz- zards, and other storms affect the built environ- ment and agriculture in every country of the world. Disasters associated with severe tropical cyclones can cover hundreds of square kilometers, lead ro hundreds of thousands of casualties, and cause billions of dollars in economic loss. Winds approaching 350 kilometers per hour (200 miles per hour), rains exceeding 80 centimeters (30 inches) in a few days, and storm surges of 8 meters (25 feet) characterize the more intense storms of this type. About 15 percent of the world's popula- tion is at risk from tropical srorms - in the southeastern United States, Japan, the Philip- pines, sonthern China, and South Asia. Particu- larly vulnerable to deadly srorm surges are the river deltas of Asia, where death tolls of 300,000 or more have been recorded in a single event. In the United States, hurricanes are more often associ- ated with widespread property damage, as in 1972, when Hurricane Agnes caused nearly $2 billion in damage - one of the costliest natural disasters in U.s. history. The United States leads in the occurrence of tornadoes, but they have also been reported in Canada, Argentina, Australasia, Bangladesh, In- dia, and Europe. The most extensive tornado- related disasters have occurred in the United States. In 1974, 149 tornadoes struck from Can- ada to the Gulf of Mexico in 36 hours, killing more than 200 and causing damage exceeding $1 billion. Wind speeds approaching 500 kilometers per hour (300 miles per hour) are possible in a tornado, and windborne debris is a significant hazard. Individual storms are small in extent (fractions of a kilometer), but outbreaks of many srorms affecting large areas (hundreds of square kilometers) are common in the United States. A tornado striking the center of a large city would certainly be a major disaster. Though it is uneconomical to design for the most intense rornado winds, the less intense winds can be effectively resisted with use of appropriate construction techniques. Improved rornado warn- ing times and instructions to the public that place people in optimum locations within buildings are credited with greatly reducing deaths and injuries from rornadoes in the United States. Extratropical cyclones, fronts, thunderstorms, and downslope winds also threaten people and