TITLE:
A Rainfall Intensity-Duration Threshold for Mass Movement in Badulla, Sri Lanka
AUTHORS:
E. N. C. Perera, D. T. Jayawardana, Pathmakumara Jayasinghe
KEYWORDS:
Rainfall Intensity-Duration, Rainfall Threshold, Landslide, Debris Flow, Cutting Failure, Slope Failure, Trigger Mass Movements
JOURNAL NAME:
Journal of Geoscience and Environment Protection,
Vol.5 No.12,
December
25,
2017
ABSTRACT: Mass movement in Sri Lanka is mainly triggered by heavy rainfall. International literature is rich of works defining rainfall intensity-duration models to identify the rainfall threshold for various types of Mass movement. However, studies have not focused to establish a relationship between intensity and duration of rainfall in Sri Lanka. Therefore, this study focused to establish rainfall intensity-duration models to identify the rainfall threshold for mass movements in Badulla district in Sri Lanka, where forty four (44) rainfall events that resulted in same number of landslides during the last three decades were considered. Results indicate the rainfall threshold relationship fits to the log linear model of the exponential function, I = α·D-β. The constructed I-D curve revealed that short duration (54 mm/h) in rainfall events can potentially trigger the landslide. However, long-duration (>8 h) and low-intensity (