Monitoring system for deep-seated landslides using locally-developed tilt and moisture sensors: System improvements and experiences from real world deployment

Landslides pose serious threat in a large number of communities living near steep and unstable slopes in the Philippines. This paper describes the enhancements in the design of an alternative instrumentation for monitoring deep-seated landslides based on tilt and soil moisture sensors. The real time landslide monitoring system is composed of a sensor column buried in a borehole, which can reach up to 40m in depth, in the unstable slope. Each column consists of 0.5-1m segments that contain a tri-axial accelerometer for tilt measurements and a capacitive sensor for soil moisture. In this manner, tilt and soil moisture measurements can be made at a resolution of 0.5 to 1m underground. Sensor measurements from each segment are accessed via Controller Area Network (CAN) protocol and transmitted to a remote host via GSM cellular infrastructure. We also describe the previous deployments in ten different sites in the Philippines as well as share the technical challenges and difficulties faced in deploying the monitoring system in real world setting. The field deployments provided valuable inputs regarding improvements in the sensor design. Furthermore, this paper discusses the experiences in involving the community at risk as part of the synergistic approach in taking progressive steps towards an effective community and technology based early warning system.