Study for assessment of rainfall duration inducing landslides

Abstract

Landslides and debris flows occur often in South Korea. Researchers have attempted to find accurate criteria for predicting these processes by analysing all influencing factors. Rainfall is one of the most important factors since its properties can change very quickly. However, until now, it has been unclear as to what duration of antecedent rainfall is the most critical and best for predicting landslides. In this study, an analysis of multiple cases of antecedent rainfall duration was conducted based on a concept that the amount of rainfall within some critical rainfall duration must be the highest among the previous periods of rainfall of the same duration. An experiment was conducted based on this critical duration concept, where the concept was true if cumulative rainfall within the antecedent rainfall duration was maximum, and false if it was not. The concept was proven true in many cases. The highest percentage (41·6%) of an individual true outcome was for an antecedent rainfall duration of 31 d. Th...