Accession Number:

ADD020440

Title:

Tsunami Detection System

Descriptive Note:

Patent application, Filed 22 March 2010

Corporate Author:

DEPARTMENT OF THE NAVY WASHINGTON DC

Personal Author(s):

Report Date:

2010-03-22

Pagination or Media Count:

17.0

Abstract:

The present invention is directed to tsunami detection. In particular, the present invention is directed to a system that can reduce the amount of time it takes to detect a tsunami by an order of magnitude by using an underwater fiber optic cable as a pressure sensor. Although tsunami waves contain tremendous energy, their distributed nature e.g., very long periods and wavelengths make detection difficult. A satellite radar sensor spanning the length of an ocean. A tsunami is considered a shallow water wave, having a large wavelength compared to the ocean depth. A tsunami can have wavelengths ranging from 100 to 500 km, and amplitudes up to 60 cm i.e., a pressure signal of up to 1 psi. A telecommunications grade optical fiber cable fitted with repeaters, can measure pressure signals over spatial cells as small as 0.5 m using Rayleigh scattering effects and optical time delay reflectometry. The tsunami pressure signals are extracted from the pressure signals generated by wind-generated water waves through signal processing to distinguish between the substantial differences in wavelength, period and propagation speed.

Subject Categories:

  • Seismology
  • Seismic Detection and Detectors

Distribution Statement:

APPROVED FOR PUBLIC RELEASE