Climate Variability & Establishment of Rainfall Threshold Line for Landslide Hazards in Rangamati, Bangladesh  

作　　者：Mahmuda Khatun Abu Taher Mohammad Shakhawat Hossain Hossain Md. Sayem Mahmuda Khatun;Abu Taher Mohammad Shakhawat Hossain;Hossain Md. Sayem(Department of Geological Sciences, Jahangirnagar University, Savar, Dhaka, Bangladesh)

机构地区：[1]Department of Geological Sciences, Jahangirnagar University, Savar, Dhaka, Bangladesh

出　　处：《Open Journal of Geology》2023年第9期959-979,共21页地质学期刊（英文）

摘　　要：This study aims to evaluate the impact of extreme rainfall events on landslides under current and past climate scenarios. Rainfall-triggered landslides are analyzed by rainfall estimates, derived using statistics of events. It is established that recent climate changes, mainly temperature and rainfall patterns have significantly increased the rainfall-induced landslide hazards in the Rangamati district, Bangladesh. It is also observed that the temperature and rainfall of Rangamati had increased gradually during the last 40 years (1981-2021). On 13 June 2017, a series of landslides triggered by heavy monsoon rains (300 mm/24 h) occurred and killed more than 112 people in the Rangamati hill district, Bangladesh. The highest annual decade rainfall is 3816 mm, recorded in 2010-21. A relationship between causalities and the number of events has also been established. The analysis shows that both antecedent and single-day major rainfall patterns can influence sliding events. It is established that monsoonal rainfall (June-September) can significantly influence catastrophic landslide hazard events. Finally, two rainfall threshold lines for the researched area are constructed based on antecedent and single-day major rainfall occurrences, as well as the number of fatalities caused by landslides. Total rainfall of 100 mm (16.66 mm/day) during six days appears to define the minimum rainfall that has led to shallow landslides/slope failures, while 210 mm (35 mm/day) within six days appears to define the lowest rainfall that could be a cause of catastrophic landslide in Rangamati district.This study aims to evaluate the impact of extreme rainfall events on landslides under current and past climate scenarios. Rainfall-triggered landslides are analyzed by rainfall estimates, derived using statistics of events. It is established that recent climate changes, mainly temperature and rainfall patterns have significantly increased the rainfall-induced landslide hazards in the Rangamati district, Bangladesh. It is also observed that the temperature and rainfall of Rangamati had increased gradually during the last 40 years (1981-2021). On 13 June 2017, a series of landslides triggered by heavy monsoon rains (300 mm/24 h) occurred and killed more than 112 people in the Rangamati hill district, Bangladesh. The highest annual decade rainfall is 3816 mm, recorded in 2010-21. A relationship between causalities and the number of events has also been established. The analysis shows that both antecedent and single-day major rainfall patterns can influence sliding events. It is established that monsoonal rainfall (June-September) can significantly influence catastrophic landslide hazard events. Finally, two rainfall threshold lines for the researched area are constructed based on antecedent and single-day major rainfall occurrences, as well as the number of fatalities caused by landslides. Total rainfall of 100 mm (16.66 mm/day) during six days appears to define the minimum rainfall that has led to shallow landslides/slope failures, while 210 mm (35 mm/day) within six days appears to define the lowest rainfall that could be a cause of catastrophic landslide in Rangamati district.

关 键 词：Climate Change Antecedent Rainfall Rainfall Threshold Catastrophic and Landslide 

分 类 号：P64[天文地球—地质矿产勘探]