The Pacific Tsunami Warning Center (PTWC) in Ewa Beach, Hawaii, USA serves as the operational headquarters of the Pacific tsunami warning system; sub-regional centres in Japan and Alaska, USA work with PTWC to provide international tsunami alerts for events occurring in the Pacific Ocean and within the marginal seas of the north- and southwest Pacific. The messages are advisories to designated national authorities, as each country is individually responsible for issuing warnings and public safety information to its population. The PTWC disseminates tsunami alerts to over 100 points across the Pacific.
To do this, the PTWC works closely with other regional and national centers in monitoring seismological and sea level stations and instruments around the Pacific Ocean to evaluate potentially tsunamigenic earthquakes, and issue alerts within 10 minutes after the event. The PTWS makes use of about 600 seismic stations around the world to locate potentially tsunamigenic earthquakes, and accesses about 500 sea level stations globally to verify the generation and evaluate the severity of a tsunami.
Extracted from PTWS Operational User's Guide 2010, US NTWC name change 2014
Pacific Tsunami Warning Center
The PTWC started in 1949 following an unwarned tsunami from Alaska in 1946 that killed 159 people in Hawaii. It is administratively part of the NOAA NWS Pacific Region. Its mission responsibilities include serving as the:
Service as the Interim Tsunami Watch Provider for the Indian Ocean (along with JMA) was discontinued in 2012.
The contact information for PTWC is:
Dr. Charles McCreery, Director
Pacific Tsunami Warning Center
91-270 Fort Weaver Road
Ewa Beach, Hawaii 96706
US National Tsunami Warning Center
The US NTWC (formerly WC/ATWC) started in 1967 after the 1964 Alaska earthquake and tsunami as the tsunami warning center for Alaska. Its area of responsibility expanded to include the west coast of North America in 1982, and to all coasts of North America in 2005. It is administratively part of the NOAA NWS Alaska Region. Its mission responsibilities include serving as the:
The contact information for NTWC is:
Mr. Paul Whitmore, Director
National Tsunami Warning Center
910 Felton St.
Palmer, AK 99645
Japan Meteorological Agency
The Ministry of Land, Infrastructure, Transport, and Toursim of Japan oversees the Japan Meteorological Agency that operates and administers the tsunami warning programme for Japan.
The Director of the Earthquake and Tsunami Observations Division within the Seismological and Volcanological Department of JMA administers the Tsunami Warning Center in Japan. The JMA National Center in Tokyo has mission responsibility as:
Service as the Interim Tsunami Watch Provider for the Indian Ocean (with USA PTWC, since 2005) was discontinued in 2012.
The contact information for the JMA Tsunami Warning Center is:
Mr. Takeshi Koizumi
Senior Coordinator for International Earthquake and Tsunami Information
Seismological and Volcanological Department
Japan Meteorological Agency (JMA)
1-3-4 Otemachi, Chiyoda-ku, Tokyo 100-8122