Development of a Fiber Optic based System to Monitor Landslide Activity

Optical Time Division Reflectometery (OTDR) was originally developed to detect breaks/losses in optical fiber transmission cables. Its use for monitoring land mass deformation has not been exploited so far. An experimental set up of a Fiber Optic System using OTDR to Monitor Landslide Activity was realised demonstrating this capability. The feasibility study used in an open configuration wherein an OTDR was used for interrogating the optical fiber subjected to a physically simulated micro-bending likely to be caused by landslide activity. Distance Estimations of micro-bend locations derived from the OTDR traces so obtained, were analysed using serial interface for the Computer and Tek FMTAP software. These were compared with actual physical distances. The paper reports the salient features, scope, operating principle, and details of the experimental set-up of a proposed Fiber Optic System to Monitor Landslide Activity. Economic advantages of the proposed system over the traditional inclinometer method include: no need to physically visit the site for collection of data, inexpensive, less time consuming, easy installation, disposable cable, no need to clean debris from the inclinometer hole before taking measurements; and ability of remote monitoring at multiple locations. The application of the OTDR techniques employing optical fiber for sensing landslide activity, its further refinement/modifications for remote monitoring are also discussed.