Techniques used for landslide monitoring by using fiber optic sensors

Abstract

A novel technique for the determination of a creeping landslide boundary is demonstrated. It is based on application of distributed optical fiber strain measurements using Brillouin Optical Time Domain Analysis (BOTDA) technology. A road crossing the St. Moritz landslide boundary was instrumented with a fiber optic cable, which turned the road, effectively, into a large scale strain gauge. The obtained monitoring data was in good agreement with visual observation and also followed the trends of the geodetical data. The presented validation of this technology allows for a conclusion that distributed fiber optic strain sensing is a promising new tool in landslide surveillance. At present, until methods and standards in this field are established and reliable, combination with traditional methods is necessary. Ongoing measurements during 2008 may strengthen the conclusions of this paper.