Patent ID: 8284072

Claim:
A method of tsunami wave detection comprising the steps of: disposing an optical fiber cable across the ocean; broadcasting an optical signal with a laser across the optical fiber cable; repeating said optical signal through the use of a plurality of optical repeaters disposed a predetermined distance from each other within said optical fiber cable, wherein said plurality of optical repeaters overcome losses in the optical signal due to attenuation; receiving a plurality of signal data from the optical fiber cable with a digital signal processor joined to said optical fiber cable, wherein the signal data represents measurements of pressure on the optical fiber cable from water waves and is measured using optical time delay reflectometry; sorting the measurements of pressure on the optical fiber cable as a function of distance along the optical fiber cable; performing a spatial fast Fourier transform on the signal data through the use of said digital signal processor joined to said optical fiber cable; plotting the results of the spatial fast Fourier transform on the signal data as a wave number bin versus power; analyzing the wave-number bin versus power plot to determine if there is significant energy in low wavenumber bins, wherein significant energy in these bins is a strong indication of a tsunami wave; performing a low pass filter on the results of the spatial fast Fourier transform to filter out noise and any non-tsunami wave energy; and analyzing the filtered results to determine if the wave number bins have crossed a threshold energy level that represents a detection and then communicating said detection.