Tsunami Warning Services

When a major undersea earthquake occurs near the coast and at a shallow depth, there is a possibility that a destructive tsunami can be generated that will impact near-by coasts within minutes and that can also traverse across entire ocean basins to wreak havoc 1000’s of miles away and up to 24 hours later. To alert far-away coasts, internationally-coordinated tsunami early warning systems have been established to provide alerts to countries on regional-to-distant tsunamis.

The mission of a Tsunami Warning Centre (TWC) is to provide early tsunami warnings on potentially destructive tsunamis. It provides this information to emergency officials, and as appropriate, directly to the public. In order to carry out its mission, the TWC uses local and global seismographic networks transmitting seismograms in real-time to continuously monitor seismicity in order to locate and size potentially tsunamigenic earthquakes. Earthquakes are the primary generators of tsunamis. Alternatively, the national TWC can receive international tsunami advisories issued by the international tsunami warning centres (such as the PTWC, WC/ATWC, and JMA), and upon receiving, evaluate the threat to their country and further disseminate the relevant information to emergency authorities. TWC also use sea level networks reporting data in real and near real-time to verify the generation and evaluate the severity of a tsunami. TWC then disseminate tsunami advisory and warning messages to designated national or local authorities for their subsequent action. TWC must respond fast, be as accurate as possible, and be reliable in order to be effective.