Regional Fixed Tsunami Warning Bulletin
Regional Fixed Tsunami Warning Bulletin : A PTWC PTWS message issued initially using only seismic information to alert all participants of the possibility of a tsunami and advise that a tsunami investigation is underway. The area placed in a Tsunami Wa rning status encompasses coastal regions within 1,000 km of the earthquake epicentre. A Regional Fixed Tsunami Warning will be followed by additional bulletins without expanding the warning area until it is either upgraded or is cancelled