Pacific Tsunami Warning Center

The facility became operational in 1948 and was called the Seismic Sea Wave Warning System (SSWWS), headquartered at the Coast and Geodetic Survey's seismological observatory in Honolulu, Hawaii.

[2] The expanded system became operational in April 1965 but, like its local predecessor, was limited to teletsunamis – tsunamis which are capable of causing damage far away from their source.

After Congress approved funding in 1965, the Alaska Regional Tsunami Warning System was launched in September 1967 with observatories in Palmer, Adak and Sitka.

[4] In 1982, the Alaska Tsunami Warning Center's area of responsibility was enlarged to include California, Oregon and Washington, as well as British Columbia in Canada, but only for earthquakes in the vicinity of the West Coast.

The responsibility for Puerto Rico and the U.S. Virgin Islands was passed to the West Coast/Alaska Tsunami Warning Center in June 2007, while PTWC continued to issue advice for other parts of the Caribbean Sea.

[4] PTWC discontinued its messages for the Indian Ocean in 2013 after regional tsunami warning centers were opened in Australia, India and Indonesia.

This happened because warnings and watches issued by PTWC caused confusion when they conflicted with a country's independently derived level of alert.

PTWC messages for other regions do not include alerts, but rather advice, as the authority to issue tsunami warnings was delegated to member states in 2014 to avoid confusion among the public.

[16] Beginning in 2005, as a result of the tsunami caused by the 2004 Indian Ocean earthquake, plans were announced to add 32 more DART buoys to be operational by mid-2007.

Each station consists of a sea-bed bottom pressure recorder (at a depth of 1000–6000 m) which detects the passage of a tsunami and transmits the data to a surface buoy via acoustic modem.