Pacific Tsunami Warning

 

PACIFIC TSUNAMI WARNING SYSTEM
PTWS OPERATIONAL USERS GUIDE, SECTIONS 2 and 3.
(as of October 2008, updated through 2018)

The Pacific Tsunami Warning and Mitigation System (TWS) is coordinated through the UNESCO IOC’s Intergovernmental Co-ordination Group for the Pacific Tsunami Warning and Mitigation System (ICG/PTWS).  One of its most important activities is ensure the timely issuance of tsunami warnings and advisories.  The Pacific TWS, through its Tsunami Service Providers (TSPs), provide international threat information to countries that have officially designated Tsunami Warning Focal Points (TWFP).  The primary objective of each TSP is to continuously detect and locate major earthquakes in its Area of Service, determine whether they have generated tsunamis, and provide timely and effective tsunami information to designated national authorities.  National authorities, such as National Tsunami Warning Centers or Disaster Management Officers, than have the responsibility to warn their coastal communities to minimize the hazards of tsunamis, especially to human life and welfare. 

The US NOAA Pacific Tsunami Warning Center (PTWC) serves as the operational center for the Pacific TWS and the PTWS.  Sub-regional centres in Japan (JMA Northwest Pacific Tsunami Adviosry Center, NWPTAC), Alaska (US NOAA National Tsunami Warning Center, US NTWC, for the US and Canada), and in China (South China Sea Tsunami Advisory Center, SCSTAC) work with PTWC to provide international threat information for the Pacific and its marginal seas.  PTWC, NWPTAC, US NTWC, and SCSTAC are Tsunami Service Providers (TSP) for the Pacific.  The TSPs collect and evaluate data provided by participating countries, and issue appropriate bulletins to both participants and other nations, states or dependencies within or bordering the Pacific Ocean basin regarding the occurrence of a major earthquake and possible or confirmed tsunami generation. The messages are advisories to national authorities, as each country is individually responsible for issuing warnings and public safety information to its own population.  

The four TSPs work closely together to ensure the timely and consistent delivering of tsunami information.  The first bulletins that are issued are usually based only on seismic information.  As tsunami wave forecasts are estimated, sea level data are received on coastal or deep-ocean gauges, and the generation of a tsunami and its severity can be confirmed, appropriate information are issued. 
The analyses and evaluations provided by the Centres, while performed using slightly different methods and data networks, generally report identical or closely similar results.  It is recommended that when discrepancies do occur, national agencies receiving the information assume the conservative or worst case scenario in making their decisions regarding life safety.

The Operational Users Guide for the Pacific Tsunami Warning and Mitigation System (PTWS, 2011) and the relevant Enhanced Products Users Guides (PTWC, 2014; NWPTAC, 2018; South China Sea Tsunami Advisory SCSTAC, 2017) gives a summary of the Pacific’s Tsunami Service Provider services.  The Guide is intended for use by the National Tsunami Warning Focal Points as customers receiving their products.   Topics include operational tsunami warning centre procedures, seismographic and sea level networks used by the warning centres, criteria for the reporting and issuing of tsunami information messages, recipients of the information, and the methods by which the messages are sent.  Annexes provide additional background on tsunamis, earthquake source characterizations, guidance on message interpretation and emergency responses, sea level measurements, travel time calculation and wave forecasting.

In October 2014, the PTWC implemented new enhanced tsunami products that include tsunami wave amplitude forecasts.  Click HERE for more information.  In December 2017, the NWPTAC commenced issuance of its enhanced products in parallel with its existing services.  In January 2018, the new SCSTAC commenced trial operations.

 

Document Title Format/Type
PTWS Operational User's Guide (2011, for services through 2014) PDF  (1.49 MB)
PTWC PTWS Enhanced Products User's Guide (IOC TS 105 rev, Aug 2014)  PDF  (4.37 MB)
NWPTAC Enhanced Products User's Guide (Draft, Jan 2018)  PDF  (745 KB)
US NTWC User's Guide (April 2017)  PDF (1.7 MB)
SCSTAC User's Guide, Tsunami Advisory Products for the South China Sea Regional Tsunami Warning and Mitigation System (Oct 2017)  PDF (2.26 MB)
Pacific and Caribbean Tsunami products (WMO heads) (July 2017)  PDF (40 KB)

 

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