Bathymetric influence on tsunami spatial/temporal patterns in HF radar currents

Observation of tsunamis with HF radar is possible because of the unique nature of the current patterns accompanying their shallow-water height profile. As these waves approach the coast, their velocity signature strengthens as the cube of the height as depth decreases. Thus the bathymetry near the radar site is the most important factor in determining the detection distance and warning time possible. We analyze these relations for both the temporal and spatial signatures, before and after the arrival of the first wave. Understanding this behavior at each HF radar location is critical in determining the effectiveness of tsunami observation and warning software, and guides the development of required pattern recognition algorithms.