Tsunami Warning Centre. Centre that issues timely tsunami messages to emergency response agencies and/ or the public. International TWC messages are advisory to a country’s TWFP. National TWC (NTWC) messages are advisory to the country’s official emergency agencies. International TWCs monitor and provide tsunami information to Member States on potential distant and regional tsunamis using global data networks, and can often issue messages within 10 minutes of the earthquake. Local TWCs monitor and provide tsunami information on potential local tsunamis that will strike within minutes. Local TWCs must have access to continuous, real-time, densely-spaced data networks in order to characterize the earthquakes within seconds and issue a warning within minutes.
An example of an International Tsunami Warning Centre (ITWC) is the Pacific Tsunami Warning Center that provides international tsunami alerts to the Pacific. Examples of Regional ITWC’s are the NWPTAC operated by the Japan JMA, and the WCA TWC operated by the US NOAA . In the Pacific, these centres, along with long-time national centres in Chile, France, and Russia, also act as national TWCs providing tsunami warnings for their countries. In the IOTWS, RTSP issue products to NTWCs through a secure service. In the PTWS and CA RIBE-EWS, PTWC, NWPTAC , and WCA TWC issue products simultaneously to TWFPs and the public. In the NEAMTWS, TWPs issue products to NTWCs and TWFPs.