開発機械／岩盤工学／資源経済と社会システム／資源開発技術

[3K0207-15-09] Hazard Mapping of Ground Subsidence in East Area of Sapporo Using Frequency Ratio Model and GIS

○Taeyoo Na¹, Youhei Kawamura^1,2, Seong-seung Kang³, Shinji Utsuki⁴ (1. Akita university, 2. North China Institute of Science and Technology, 3. Chosun University, 4. Consulting company of Utsuki Geo Solution)

The chairman: Daisuke FUKUDA (Hokkaido University)

Keywords:Ground Subsidence , Earthquake, Susceptibility map, Frequency ratio model, GIS

As an earthquake occurred in Iburi subprefecture, southern Hokkaido, Japan on September 2018, Sapporo city has also damaged by ground subsidence due to earthquake. Ground subsidence can occur in various area, especially in urban areas and mine sites causing considerable damages of human lives and properties. Currently, ground subsidence is one of the most important problems not only in Japan but all over the world. However, quantitative research about ground subsidence due to earthquake that particularly occurred in the urban area and mine site was not well studied. To prevent and minimize the critical damage caused by subsidence, this study aims to construct hazard map to predict susceptible subsidence place around in East area of Sapporo city, using Geographic information System (GIS) and Frequency ratio model (FR). To determine major factors related to ground subsidence, spatial databases were constructed from geological map, slope data, land use map, borehole data, precipitation data, rail roads and subway data earthquake information data. Weight of each factors were estimated by frequency ratio model to analyse degree of subsidence hazard and ground subsidence hazard map created by GIS. Constructed susceptibility subsidence hazard map was compared with reported actual ground subsidence area in Sapporo city to verification. The results of verification showed accuracy of 85.17% between the predicted hazard map and the actual ground subsidence areas. Verification results showed sufficient possibility for reliable susceptibility mapping of ground subsidence using GIS and frequency ratio model. With the same methodology, in the case of mine site, ground subsidence hazard mapping would be possible by considering major parameters according to kinds of mine. Furthermore, this method could provide a reference for safety and production in the mine sites.