We would use that: we don't call it a tsunami warning system.
Times, Sunday Times (2011)
No tsunami warning was issued.
Times, Sunday Times (2016)
The tsunami warning centers require accurate, timely and reliable tide data during a large potentially tsunamigenic earthquake.
T.J.Sokolowski, A.H. Medbery, G.W. Urban 2001, 'USING A SATELLITE TELEPHONE TO RETRIEVE TSUNAMI DATA FROM TIDE SITES IN THE PACIFIC BASIN', Science of Tsunami Hazards