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 Sea, face the greatest tsunami hazard, but West Coast states could see the funding to prepare for such an event dwindle. The federal government is expanding its tsunami preparedness program to the East and Gulf Coasts, where the risk of deadly tsunami waves is low, limiting resources in the areas that need them the most, according to a new report from the Government Accountability Office.
The GAO says five Pacific states receive approximately $275,000 per year from the National Tsunami Hazard Mitigation Program. However, as the program is expanded this year to allow 23 additional states and territories to apply for a share, “it will be difficult for NOAA to ensure that the most threatened states receive the resources they need to continue and to complete key mitigation activities,” the report said.
The GAO advised the National Oceanic and Atmospheric Admini-stration, a lead agency for the program, to evaluate the costs and benefits before moving ahead. A significant expansion of federal tsunami detection, warning and related activities, as well as the NTHMP, is underway. However, the future direction of these efforts is unclear because NOAA has not developed long-range strategic plans to guide them,” the GAO report noted.
Under NTHMP, NOAA provides funding and technical support to help states produce inundation maps, assess tsunami hazards, improve and coordinate warning systems, and develop state and local tsunami hazard mitigation programs.
A tsunami is a series of ocean waves typically generated by an underwater earthquake, although landslides, volcanic activity and meteor strikes also may generate a tsunami, the GAO report said. “A tsunami wave may be small in the ocean, but as it approaches land, it can increase to tens of feet in height and reach shore as a fast-moving wall of turbulent water, often at speeds up to 600 miles per hour,” the report said.
“Tsunamis pose an inundation threat to low-lying coastal communities from multiple destructive waves that can penetrate far inland. Distant tsunamis travel long distances from their triggering events to strike the coast hours later. Local tsunamis strike the coast minutes after their near-shore triggering event, allowing little time for warning and evacuation,” GAO explained.
According to NOAA’s records, the last tsunami that caused significant damage was at Skagway Alaska in November 1994. During that event, a landslide and associated tsunami caused one death and $25 million in damages. Hawaii suffered its greatest tsunami death and destruction in 1946, when 159 people were killed.
Yet “the devastation caused by the Indian Ocean tsunami in December 2004 demonstrates the need for assessing the threat, and for monitoring and preparing for an event in at-risk areas, particularly low-lying, seismically active coastal areas,” the report said.
The Indian Ocean tsunami killed more than 200,000 people, displaced more than 1.4 million and caused significant damage in 12 countries in Asia and East Africa.
The GAO report indicated that high-hazard tsunami areas have been identified, but limited information exists on the likely impacts of a tsunami in those areas. Some coastal areas lack inundation maps showing the potential extent of tsunami flooding in communities, and other communities have unreliable maps, the report indicated.
Inundation maps are the “foundation” for evaluating potential impacts on communities, showing the extent to which a tsunami would penetrate inland and flood communities, GAO said.
Alaska has inundation maps for only 5 of 60 at-risk communities. GAO said maps are limited because accurate maps are complex and costly to produce.
Additionally, state assessments of tsunami impacts on people and infrastructure have been limited in part because of a lack of loss estimation software, which exists for other disasters such as floods, hurricanes and earthquakes, GAO added.
Federal warning centers are able to detect potential tsunamis and issue warnings, but false alarms and warning system limitations hamper their effectiveness. The report indicated that 16 warnings issued since 1982 were not followed by destructive tsunamis on U.S. shores, potentially causing people to ignore the warnings. Additionally, warnings have been delayed or were not able to be transmitted to some locations, in some cases.
In June 2005, a 7.2 magnitude earthquake off of California triggered tsunami warning for the West Coast, but signal problems prevented the warning from reaching portions of the coasts of Washington and Oregon, the report said. Although a tsunami did not occur, the event tested emergency response systems. Many 911 dispatch centers and telephone lines were overloaded, in some cases, preventing local emergency managers from quickly disseminating the warning to their local officials and preventing telephone-based warning systems from reaching residents, the report noted.
Most at-risk communities have mitigated potential tsunami impacts through planning, warning system improvements, public education and infrastructure protection, but the level of implementation varies, the report indicated. “Key educational efforts, such as distributing evacuation maps and developing school curricula have not been consistently implemented,” the report said.
According to GAO, the plan that NOAA is using to guide the expanded NTHMP activities to 23 additional has not been updated since 1996. Thus, there are concerns that funding decisions and strategic direction for the plan will become less risk-based as states with relatively low hazards join the program. Furthermore, NOAA does not have NTHMP outcome goals and performance measures for reducing false alarms or other critical activities such as mapping, modeling, research, education and outreach, GAO said.
“Tsunamis are an infrequent hazard that may be overlooked due to higher priority reoccurring natural hazards such as hurricanes and flooding,” GAO noted, so “NOAA and its federal and state partners face a significant challenge ensuring that communities are sufficiently engaged in preparedness activities.”
Nevertheless, of the approximately 500 coastal communities at-risk from a tsunami in five Pacific states and Puerto Rico, only 25 communities have been recognized by the National Weather Service as “TsunamiReady.” Such data underscores the need to address the shortcomings and develop a more strategic mitigation program, GAO concluded.
To view the full GAO report, visit http://www.gao.gov/new.items/
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