DEVELOPING AN EARLY WARNING SYSTEM BY MONITORING EARTHQUAKE-INDUCED LANDSLIDES THROUGH FIBER OPTICS

Landslides are one of the most destructive natural disasters causing loss of life and considerable economic problems. Although many factors can trigger landslides, seismic loading is one of the most significant factors. There are many methods used for detecting/monitoring landslides such as inclinometers, and ground-based surface measurement systems. Although they possess various advantages, fiber optic systems are becoming increasingly popular for monitoring landslides due to their fast and easy data transfer ability, compact size and lightweight, high sensitivity to unit deformation and temperature changes, wide bandwidth capabilities, resilience to environmental and electromagnetic factors, low cost, and ability to perform continuous monitoring. This study aims to establish a landslide monitoring system by employing fiber optic cables to simultaneously monitor deformations triggered by earthquakes on the landslide failure surface. Within the scope of this study, a landslide container holding an artificial slope was emplaced on a shaking table along with different sensors (i.e., fiber optic cables, LVDTs, high-resolution cameras, and accelerometers) in the laboratory to monitor the deformations under cyclic loading. The deformation developed on the slope was measured by fiber optic cables in terms of strain through a Brillouin Optical Time Domain Analyzer (BOTDA) based system. In addition, the measured deformations were verified by LVDTs located at the same level as fiber optic cables. Also, high-resolution cameras were employed to detect the surface deformation. Moreover, accelerometers were positioned within the slope model to consider the dynamic site response. To determine the sensiti vity of the different fiber optic cables, a series of experiments were conducted on the shaking table at different velocities along with varying amplitudes. The laboratory tests were concluded with the selection of feasible fiber optic cables for a real-time field application. The sensitivity analysis results of the laboratory studies serve as a base for the field application planned with the fiber optic system installed in the landslide in Yalova province of Turkey which possesses high earthquake hazard potential. The proposed system is expected to evaluate the landslide movements caused by earthquakes from different points of view, and hence, be used as a monitoring and early warning system for landslides, especially in earthquake-prone areas.