National Tsunami Warning Center

The National Tsunami Warning Center (NTWC) is one of two tsunami warning centers that are operated by the National Oceanic and Atmospheric Administration (NOAA) in the United States. It was called the West Coast and Alaska Tsunami Warning Center (WC/ATWC) until October 1, 2013. The name was changed to reflect its geographical zone of responsibility. Headquartered in Palmer, Alaska, the NTWC is part of an international tsunami warning system (TWS) program and serves as the operational center for TWS of all coastal regions of Canada and the United States, except Hawaii, the Caribbean, and the Gulf of Mexico. The other tsunami warning center is the Pacific Tsunami Warning Center (PTWC) in Ford Island, Hawaii, serving participating members and other nations in the Pacific Ocean area of responsibility.

Following the March 27, 1964 Alaska earthquake and tsunami, the NTWC (formerly known as The Palmer Observatory) was established in 1967 in Palmer, Alaska under the auspices of the Coast and Geodetic Survey. This earthquake alerted State and Federal officials that a facility was necessary to provide timely and effective tsunami warnings and earthquake information to the coastal areas of Alaska. Congress provided funds in 1965 to construct two new observatories and establish a tsunami warning system in Alaska. The first observatory constructed was at the U.S. Naval Station on Adak Island in the Andreanof Islands in the Central Aleutians. The City of Palmer, in the Matanuska Valley 42 miles northeast of Anchorage, was selected as the site for the primary observatory due to its proximity to bedrock for instrumentation and to communications facilities. Construction of the observatory installations, the task of engineering and assembling the data systems, and the hookup of the extensive telecommunications and data telemetry network was completed in the summer of 1967. With the dedication of the Palmer Observatory on September 2, 1967, the Alaska Regional Tsunami Warning System (ARTWS) became operational.

Originally, the tsunami warning responsibility for Alaska was shared by the three observatories located at Palmer, Adak and Sitka. Sitka, a seismological observatory since 1904, and Fairbanks were the only two seismic stations operating in Alaska in 1964. The responsibilities of Adak and Sitka were limited to issuing a tsunami warning for events occurring within 300 miles of their location. In later years, the responsibility to provide tsunami warning services for Alaska was transferred from the Adak and Sitka observatories to the Palmer Observatory. Sitka and Adak Observatories were eventually closed in the early 1990s, although the seismic instrumentation is still maintained.

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