High-Risk U.S. Coastal Areas Not Prepared for Tsunami

WASHINGTON, DC, June 23, 2006 (ENS) - The federal government needs better information about the likely impacts of a tsunami in the highest risk areas of the country, according to a new report by the investigative arm of Congress.

The high risk areas are the Pacific coast states of Alaska, California, Hawaii, Oregon and Washington, as well as Puerto Rico and the U.S. Virgin Islands in the Caribbean. The Atlantic and Gulf coasts are at lower risk for this hazard.

The Government Accountability Organization (GAO) prepared the report in response to a request by Senator Dianne Feinstein, a California Democrat. It was presented to her and to Congressional committees this week.

A tsunami is a series of ocean waves generated by sudden displacements in the sea floor, landslides, or volcanic activity. In the deep ocean, the tsunami wave may only be a few inches high. The tsunami wave may come gently ashore or may increase in height to become a fast moving wall of turbulent water several meters high.

The December 2004 Indian Ocean tsunami raised questions about U.S. preparedness for such an event.

Although a tsunami cannot be prevented, the impact of a tsunami can be mitigated through community preparedness, timely warnings, and effective response.

Most of the states and some communities GAO visited have basic mitigation plans identifying tsunami hazards, but false alarms and technical limitations hamper the effectiveness of emergency warning systems.

The Indian Ocean tsunami of December 26, 2004 resulted in a total of 229,866 persons lost, including 186,983 dead and 42,883 missing. This photo was taken as the wave came ashore in Thailand. (Photo courtesy David Rydevik)

NOAA officials reviewed a draft of this report and generally agreed with the findings and recommendations.

Some coastal areas lack inundation maps showing the potential extent of tsunami flooding in communities, and others have maps that may be unreliable.

State assessments of likely tsunami impacts on people and infrastructure have been limited due to a lack of tsunami loss estimation software, which exists for floods and other hazards.

The GAO said federal warning centers quickly detect potential tsunamis and issue warnings, but false alarms are a problem. Some state and local emergency managers have raised concerns about false alarms - the 16 warnings issued since 1982 were not followed by destructive tsunamis on U.S. shores - potentially causing citizens to ignore future warnings.

The GEO found that limitations in the Emergency Alert System and NOAA Weather Radio All Hazards may impede timely warnings to communities. For example, signal coverage for these two systems is insufficient to transmit warnings to some coastal areas and failure to properly activate them has resulted in warnings being delayed or not transmitted to some locations.

NOAA has begun addressing false alarms but, according to agency officials, has only conducted "live" end-to-end testing of the warning systems in Alaska to identify problems, lacking the states' permission elsewhere.

The at-risk communities GAO visited have mitigated potential tsunami impacts through planning, warning system improvements, public education, and infrastructure protection, but the level of implementation varies considerably by location.

While all of these locations have multiple warning mechanisms in place, disruptions to key infrastructure such as telephone lines may hamper timely warnings, the GAO investigators wrote in their report.

Key educational efforts, such as distributing evacuation maps and developing school curricula have not been consistently implemented.

Few states and communities protect critical infrastructure from tsunamis through land-use and building design restrictions, the GAO found.

Emergency managers attributed variability in their efforts to the need to focus on more frequent hazards like wildfires and to funding limitations. Few communities participate in NOAA's preparedness program, according to NOAA officials, because they perceive the threat of a tsunami to be low.

The nationwide expansion of NOAA's tsunami activities is under way, but the GAO says the future direction of these efforts is uncertain because they lack long range strategic plans.

NOAA has yet to identify long range goals, establish risk-based priorities, and define performance measures to assess whether its tsunami-related efforts are achieving the desired results.

NOAA leads U.S. detection and warning efforts and partners with federal and state agencies in the National Tsunami Hazard Mitigation Program to reduce tsunami risks. In 2005, Congress appropriated $17.24 million in supplemental funding towards these efforts.

Find out more about tsunami preparedness at: http://www.tsunami.noaa.gov/ and at: http://nctr.pmel.noaa.gov/