Landslide Early Warming Configuration with 50Hz GNSS and GB-SAR in Mountain Region of Taiwan

Possible landslide zone is chosen from historical events, triggering factors, terrain and many others. Only rainfall induced landslide is considered as the candidate site, and it could be as many as thousand cases for any incoming typhoon or storm in Taiwan. Movements gathered by satellite In-SAR; rock strength estimation of slope is managed by GIS to select the possible sites of the most dangerous slope. Install a pair of 50 Hz GNSS on the slope to obtain the baseline change to reveal the stability and meanwhile the derived wet delay of GNSS signals at various azimuth and directions offer better prediction of rainfall intensity than QBSUM. Once the estimate rainfall will over the threshold of slope unit then the Ku band GB-SAR is deployed to capture the real-time slope movement. The average slip rate of slope surface movement is recorded via different amount of rainfall, whenever continuous 3-time detected slip rate or 3 monitored sub-zone are exceeded than averaged slip value then a landslide warning is issued. It took 5 minutes to calculate the GNSS wet delay for the next half hour rainfall estimation; 3 minutes by GB-SAR to detect and validate the slip rate of slope. This configuration could detect mm level slope movement within hundreds meter distance or cm level in 2 Km away from the slope.