A Tsunami Watch is a notification of a possible tsunami threat after an undersea earthquake has been detected and analysed. When the threat is confirmed or the potential tsunami may impact on NSW in less than 90 minutes a Tsunami Warning will be issued. A Tsunami Watch will typically be issued less than 30 minutes after an earthquake. Three types of Tsunami Watches exist; all have the same technical meaning but differ in the areas they apply to: (1) National Tsunami Watch issued in the context of Australian region. (2) NSW Tsunami Watch issued in the context of NSW only. Issued when there is a warning for some part of the Australian region. (3) Lord Howe Island Tsunami Watch - issued in the context of Lord Howe Island only. Issued when there is a warning for some part of the Australian region. Tsunami Watches can be cancelled if the situation is reassessed as no threat. Tsunami Watches are issued by the Bureau of Meteorology and are distributed to all media outlets and emergency management agencies