HF Radar Detection of Tsunamis

This paper demonstrates that HF radar systems can be used to detect tsunamis well before their arrival at a coastline. We solve the equations of motion and continuity on the ocean surface using models to simulate the signals produced by a tsunami approaching the east U.S. coast. Height and velocity profiles are derived along with expressions for the radar-observed current velocities in terms of bathymetry and tsunami height and period. Simulated tsunami-generated radial current velocities are superimposed on typical maps of radial velocity generated by a Rutgers University HF radar system. A detection parameter is defined and plotted to quantify the progress of the tsunami, which is shown to be detectable well before its arrival at the coast. We describe observations/warnings that would have been provided by HF radar systems at locations in the path of the 2004 Indian Ocean tsunami.