Cross continental propagation of surface wave energy

In the previous section, we showed there is very good correlation between ocean wave heights and seismic excitations. We believe that the energy in ocean waves is converted to elastic energy close to the coast and propagates over the array and this elastic energy can excite the continuous oscillations of the Earth. To confirm this hypothesis, we need to show the elastic energy generated from the ocean wave can propagate long distance to finally be able to excite normal modes of the Earth. We selected several high dynamic range, very broad band seismometers deployed in the United States and computed their power spectral densities at long periods between 50 to 350 s to check if there is similar trend we found in oceanic and seismic data near the coast of California (Figure 13.27). We can clearly see two large amplitude peaks in PSD on day 31 and 33 at all three stations (CMB, TUC, and HRV).

Figure 13.27: Power spectral densities at three stations. The unit for (b), (c) and (d) is $10{\times }log(m^2s^{-4})/Hz$.
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