Empirical Approach Based Rainfall Threshold Estimation for Landslide Occurrence in Cox's Bazar District, Bangladesh

Rainfall threshold estimation empirically to forecast rainfall-induced landslide events provides crucial information reduce impact. The triggered by rainfall are common in Cox's Bazar district, especially during the monsoon season. Geological settings and climatic conditions make this area more landslide-prone leading huge losses of lives property. Establishing an effective early warning system based on a value has become top priority save people's lives, economy, environment. We have employed three empirical approaches estimate thresholds. Intensity-Duration, Event-Duration, Antecedent thresholds most conventional methods identify lowest amount that triggers landslide. Intensity-Duration (ID) Event-Duration (ED) equations calculated using simple power-law curve. For 5% exceedance probability level ID defined as: T5: I = 3.63 D-0.1313 & ED as E D0.8687. Similarly, for 1% T1: I= 2.78 D0.8687 ED. Both minimum equations. Since line delineates lower end all observed data points events, it is considered Bazar. According equation, mean intensity 2.39 mmh-1 or 57.4 mm cumulated 24 hours required initiate event. Whereas, longer duration such 120h, 1.93 continuous 232 appears be sufficient initiation. There less than chance below limit. In context 3-day 5-day antecedent thresholds, we found 130 72 h (3-day) 210 120 (5-day) could compared our with few global local estimates. Dhaka University Journal Earth Environmental Sciences, Vol. 11(1), 2022: 81-94