기후변화에 따른 도심지역 지질재해 리스크 체계 마련 = The Study for Development of Climate Change Caused Urban Geological Hazards Risk Assessment System

다국어 초록 (Multilingual Abstract)

This study analyzes the quantitative relationship between the volume of domestic rainfall and landslide vulnerability based on the analysis of causes of urban geologic hazards with a particular focus on landslides. It also analyzes factors and measures for risk assessment while aiming to present suggestions for the development of a future geological risk assessment system. To accomplish this goal, the study selected the Umyeon-san case, a recent climate change induced urban landslide which resulted in casualties and material damages. Using this case, the study examines recent research trends, analysis methods as well as causes of the landslide. The result indicates that a great share of research has been conducted on climate change scenario downscaling in recent days. However, spatial statistical analyses based on probability statistics models have been done separately from climate change scenario downscaling, which implies that the assessment of risk and geological vulnerability factoring in future climate change scenarios is at an early stage. In this study, for a quantitative analysis of correlation between rainfall and landslides occurrence, data on rainfall and landslides in Korea in the 2000s was analyzed to calculate numerical values of correlation between the occurrence of landslides and rainfall volume (daily and accumulated) and maximum hourly intensity of rainfall. Cases of landslide were concentrated in mid to end of July and that of August when daily precipitation volume was very high. Daily rainfall exceeding 164.5mm is categorized as high risk for landslide. Rainfall that continued for three days was found to affect the occurrence of landslide in Korea in the 2000s more than any other number of days during which precipitation lasted. The correlation between the intensity of hourly rainfall and landslide occurrence was most apparent in 2002, 2003 and 2006 which were the same years when Korea had significant damages from typhoons. Finally, the analysis of rainfall intensity and landslides in Korea in the 2000s together with the rainfall threshold for landslide initiation presented by Caine shows that the landslide cases in the period corresponded to rainfall intensity exceeding the threshold, except in 2004. This implies that the rainfall pattern is highly correlated with landslide initiation in Korea. Based on the analyses, this study presents suggestions for landslide risk assessment system by examining assessment factors, assessment methods and base data for assessment. In terms of assessment factors, data forms and scales have been discussed and the use of large-scale data is recommended that can meet the needs of analysis on city areas. As for assessment methods, the GCI method has been suggested, and its possible applications examined, as a way to improve the existing impact and vulnerability assessment based on expert surveys. Lastly, the study discusses uncertainty involved in base data for assessment which arises because of the nature of climate change itself and suggests the use of various climate scenarios and forecasting methods to reduce the uncertainty.