Q: What happens after a warning goes out? Has the U.S., or another nation been able to evacuate coastal areas in response to a warning, and if so, how quickly?
A: Both the PTWC and WC/ATWC are regional Tsunami Warning Centers. They are responsible for issuing local tsunami advisories, alerts and warnings for local tsunamis triggered by a local seismic event. When a warning for a local tsunami is issued, each State’s Emergency Managers (EM) Office is quickly notified. The decision to evacuate a coastal area rests with each responsible EM. The PTWC also serves as the Tsunami Warning Center for the Pacific. Under this mandate, PTWC issues tsunami bulletins, advisories and warnings for teletsunamis. For such Pacific Basin teletsunamis, PTWC relies on its network of national and international seismic and oceanographic stations to pinpoint the exact location and magnitude of a seismic event, and determine whether a tsunami has been generated. If PTWC determines that a destructive tsunami has been generated, tsunami warnings are issued. These warning include seismic data, potential tsunami (wave) heights and projected impact (travel) times.
As an example, a teletsunami generated by a South American seismic event would take 12-13 hours to reach Hawaii. For a local Hawaii, Alaska, or West Coast seismic event generating a tsunami, travel times for the immediate area are minimal. For such local events, it is critical that the public is fully aware of tsunami hazards – and the need to immediately evacuate the coastal areas. For the States of Hawaii, Alaska, Washington, Oregon and California, tsunami sirens are used to alert the public. Additionally, NOAA, under its National Tsunami Hazard Mitigation Program (NTHMP) has embarked upon an aggressive inter-governmental, multi-pronged effort to (1) improve the US’s tsunami warning capabilities (2) improve tsunami hazard assessment (produce local tsunami inundation maps) and (3) develop localized tsunami hazard mitigation programs including public awareness and community awareness (TsunamiReady Communities).
And yes, other nations (Japan in particular) as well as the U.S. (in Hawaii) have been able to quickly and effectively evacuate key coastal population centers in direct response to Regional and PTWC-issued tsunami warnings.
Q: Why haven’t the other Indian Ocean Nations joined as members of the United Nation’s UNESCO/IOC/International Coordination Group on Tsunamis?
A: The UNESCO/IOC/IGC/ITSU in its Master Plan has recognized the need to establish tsunami warning centers for areas of the earth beyond the Pacific Basin that are vulnerable to Tsunamis. These areas include the Indian Ocean Basin. UNESCO/IOC/IGC/ITSU has convened a Working Group on the Tsunami Warning System in the Southwest Pacific and Indian Ocean and has encouraged non-ITSU Member States in the Indian Ocean basin to contact the IOC Secretariat to request membership in the IGC/ITSU. As a result of the Indian Ocean Tsunami, the IOC/IGC based on its mandate and experience with ICG/ITSU, will lead an effort to expand the currently existing system in the Pacific to the World Ocean to ensure that appropriate warning systems are available in all regions of the world that are prone to Tsunamis. This decision is fully consistent with the current initiative to build a Global Earth Observation System of Systems. For that purpose immediate consultations will be undertaken with the Officers of ICG/ITSU and representatives of concerned countries.