Tsunami

One of the more recent changes in the ITWS is that the Regional Centers will be taking on greater responsibility for tsunami detection and warning procedures. This is being done because there have been occasions when the warning from Hawaii came after the tsunami hit the area. This can occur with local and regional tsunami that tend to be smaller in their area of effect. Some seismically active areas need to have the warning system and equipment closer than Hawaii if they are to protect their citizens. For example, the Aleutian Islands near Alaska have two to three moderate earthquakes per week. As of May 1995, centers such as the Alaska Tsunami Warning Center located in Palmer, Alaska, have assumed a larger role in the management of tsunami warnings.

In terms of basic research, one of the biggest areas of investigation is the calculation of return rates. Return rates, or recurrence intervals, are the predicted frequency with which tsunami will occur in a given area and are useful information, especially for highly sensitive buildings such as nuclear power stations, offshore oil drilling platforms, and hospitals. The 1929 tsunami in Newfoundland has been studied extensively by North American researchers as a model for return rates and there has been some dispute. Columbia University researchers predict a reoccurrence in Newfoundland in 1,000-35,000 years. However, a marine geologist in Halifax believes that it may reoccur as soon as 100-1,000 years. His calculations are based on evidence from mild earthquakes and tsunami in the area. He also suggests that the 1929 tsunami left a sedimentary record that is evident in the soil profile, and that such records can be dated and used to calculate return rates. He is currently working with an American scientist to test this theory.