Five distinct temporal patterns govern how the pandemic flu spread throughout the US. The normalized temporal amplitude is plotted against the total number of days (Apr 1, 2009-Mar 31, 2010). Observe the distinct lag in each of the five patterns, with successive H
indicating the peak shift occurring towards the left (indicted by a gray arrow). These patterns summarize the different peaks during the H1N1 pandemic. Notably, H1, H4 and H5 capture the late, middle and early H1N1 pandemic peaks occurring within the entire country.