PTWC Responsibilities

Areas of Responsibility

NOAA's two Tsuami Warning Centers (PTWC and WC/ATWC) have separate areas of responsibility, which are the geographical areas within which each Center has the responsibility for the dissemination of messages and the provision of interpretive information to emergency managers and other officials, news media, and the public. These are shown on the map below.

Pacific - International

As the primarly operational headquarters for the Pacific Tsunami Warning System, PTWC provides warnings for Pacific basin teletsunamis (tsunamis that can cause damage far away from their source) to almost every country around the Pacific rim and to most of the Pacific island states. This function is carried out under the auspices of the UNESCO/IOC International Coordination Group for the Pacific Tsunami Warning System. A few destructive teletsunamis are generated each century by great earthquakes around the Pacific rim. Such tsunamis can propagate across the entire Pacific in less than 24 hours, and cause widespread destruction along shorelines located thousands of miles from the source. With ever-increasing population and development along most coastlines, there is a corresponding increase in risk. The last destructive teletsunami occurred in 1964 following the great Alaska earthquake.

Pacific - U.S. Interests

As a U.S. National Tsunami Warning Center, PTWC provides warnings for teletsunamis to Hawai`i, Guam, American Samoa, Wake Island, Johnston Island, the Commonwealth of the Northern Marianas, the Federated States of Micronesia, the Republic of the Marshall Islands, and all other U.S. interests in the Pacific located outside WC/ATWC's area of responsibility (Alaska, British Columbia, Washington, Oregon, and California). PTWC serves as a backup to WC/ATWC.

Hawai`i

As the Hawai`i Regional Tsunami Warning Center, PTWC provides a more rapid warning for local tsunamis generated in Hawaiian waters. Two significant local tsunamis have been generated in Hawai`i in historical times, one in 1868 and one in 1975. Both were caused by major earthquakes that displaced the sea bottom along the southeast flank of the island of Hawai`i. Although these tsunamis caused damage and casualties only on that island, a future local tsunami could have adverse effects further up the island chain. Local tsunamis strike nearby shores almost immediately after being generated by the earthquake. Consequently, the earliest warning for a local tsunami is the strong shaking of the ground, and persons near the shoreline that feel strong shaking should evacuate immediately without waiting for an official warning.

Indian Ocean

PTWC is the interim warning center for the Indian Ocean Tsunami Warning System.

Caribbean Sea

PTWC is the interim warning center to countries in the Caribbean Sea.

Caribbean Sea - U.S. Interests

From 2005-2007, PTWC was the interim warning center to U.S. Interests (Puerto Rico, Virgin Islands) in the Caribbean Sea.

South China Sea

PTWC is the interim warning center to nations bordering the South China Sea (China, Macao, Hong Kong, Taiwan, Philippines, Malaysia, Brunei, Indonesia, Singapore, Thailand, Cambodia, Vietnam).

United States mainland and Canada

WC/ATWC is the primary warning center for the western and eastern coasts of the United States mainland and Canada.