The National Tsunami Warning Center (NTWC) serves the continental United States, Alaska and Canada. The Pacific Tsunami Warning Center (PTWC) directly serves the Hawaiian Islands, the U.S. Pacific and Caribbean territories, and the British Virgin Islands and is the primary international forecast center for the warning systems of the Intergovernmental Oceanographic Commission of the United Nations Educational, Scientific, and Cultural Organization in the Pacific and the Caribbean and Adjacent Regions.
The warning centers have Atom feeds available that can be monitored for product updates.
The NTWC Twitter feed and/or the PTWC Twitter feed can be used to receive text messages. In the U.S. you can send a text message to 40404 with 'follow NWS_NTWC' for NTWC messages, and 'follow NWS_PTWC' for PTWC messages. To stop receiving NTWC text messages, you can text 'stop NWS_NTWC' to 40404.
For more details on Twitter and SMS, please click the Twitter SMS help page
NOTE: Not all countries/carriers use 40404 - please refer to the Twitter short or long code page.
The UNESCO/IOC service will provide NTWC bulletins for seismic events greater than magnitude 6.5 . Other tsunami warning centers provide information to this list also
National Weather Service Systems
Other Federal Systems