Purpose. The aim of the work is to study the possibility of real-time tsunami forecasting based on the data from the deep-ocean tsunameters.

Methods and Results. The express method makes it possible to compute in advance the waveforms of the expected tsunami in the ocean, as well as near the coast. Forecasting requires seismological information on the start time and coordinates of the earthquake epicenter only, and also the data from one deep-ocean tsunameter obtained in real time. The data from the deep-ocean tsunameters closest to the tsunami sources with the duration equal to the tsunami first half-period (the first period) were used in the numerical experiments. The results of computing tsunamis for 2007–2015 agree quite well with the tsunami forms recorded at the deep-sea stations in the ocean in different directions from the source. The quality of computations in the article is comparable to the computation quality of the other authors. A tsunami forecast at the given points is possible immediately after receiving the information on passing of the tsunami first period through the deep-sea tsunameter closest to the source.

Conclusions. In contrast to the other methods, no reconstructing of a seismic source neither a giant base of synthetic mareograms is required for the express method. The express method can be used for tsunami forecasting in those areas for which other methods are not applicable (for example, there is no a database of synthetic mareograms), namely the coast of the northwestern Pacific Ocean.