Monday, March 19, 2018

Forecasting and warning of landslides

Landslide monitoring and early warning systems for landslide occurrence and prediction
An integrated wireless sensor network system for real-time monitoring and early warning of landslides has been carried-out in India. It consists of Intelligent Wireless Probes (IWP) to capture relevant landslide triggering parameters. The network of IWPs is used to derive the local or regional contribution of geological, hydrological and meteorological factors towards the initiation of a potentially imminent landslide. This heterogeneous sensor system provides the capability for gathering real-time context aware data to understand the dynamic variability in landslide risk. The system enhances the reliability of landslide warning, reduced false alarm rate and provides the capability to issue warnings at local and regional levels. An early warning system is an effective measure to reduce the damage caused by landslides by facilitating timely evacuation of residents from a land-slide prone area. Early detection of landslide triggering across a broad range of natural terrain types can be accomplished by monitoring rainfall and the physical property changes in soils in real-time or near real-time. This can be conducted by installing real-time monitoring system to observe physical property changes in soils in a valley during rainfall events. Laboratory experiments have shown that volumetric content of water is a prime parameter to evaluate the stability of a slope. Hence, landslide monitoring can be based on volumetric water content and its changes over time over shallow soil depths. It has been shown that a high amount of rainfall combined with a high gradient of volumetric water content induces a slope failure. This suggests a threshold value of volumetric water that separates conditions for slope stability and slope failure. Hence this threshold value can be used as an early warning system for landslides.

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