A Program to Provide Precursory Warnings for Rainfall-induced Landslides

Taiwan is a mountainous and alpine island which has more than 70% of its land area occupied by hills and mountains. Every summer, Taiwan is frequently hit by typhoons which bring along heavy rains. As a result, slope failures are a common occurrence. Using historical landslide data and statistical analysis, this study developed a program to compute the short-term and the long-term rainfall indices that can be used in the slope monitoring to provide early warnings of landslides. The program was tested on a past landslide at Houshanyue, and the results indicated a strong cause-effect relationship between Typhoon Sinlaku and the slope failure in September of 2008. Since the program was verified with good predictability and virtually no false alerts, it is believed that the program can have wider applicability in the future offering the possibility to be integrated into a more comprehensive disaster warning system to suit the needs of a wide range of rainfall-induced disasters.