Fiber Optic Distributed Strain Sensing for Seismic Applications

Abstract

Fiber optic distributed strain sensing relies on the interrogation of an optical fiber using an appropriate light source, typically a laser. When light travels through an optical fiber, it interacts with the fiber glass structure. The interaction can be elastic (Rayleigh) or inelastic (Raman or Brillouin) scattering phenomena. Among other, the scattered light can carry information about the current elongation of the optical fiber. Comparing the elongation from successive measurements, strain changes can be detected with a high temporal and spatial resolution. If a fiber optic cable is coupled to the ground, these strain changes are a measure of the ground motion and can hence be used for seismic applications.