Fault zone characterization and structural analysis

Abstract

The analysis of the characterization of faults and fractures was to gain a better understanding how geological structures affect geohazards (e.g. slope stability) and fluid flow (e.g. CO2 leakage). We surveyed slope failure in sedimentary rocks in Daegu, SE Korea. We then performed analysis using satellite images and aerial photographs, and we then carried out detailed mapping on well-exposed road-cut sections to understand their structural characteristics. Generally, slope failure during construction is only observed on the south dipping slope, indicating slope stability may depend on the relationship between dip directions of bedding and the angle of the slope. Large fault zones and parallel fractures showed consistent failure even after construction in the rainy season. We suggest a new method that uses accumulated fracture density to precisely identify fault damage zones. In particular, evaluation of slope stability on multi-face slope is more difficult than on single-face slope. Our study understands all the characteristics of geological structures in sedimentary rocks, this study will increase both work efficiency and slope stability. The leakage of underground natural hydrocarbons helps us to gain a better understanding of CO2 surface leakage and the geological controlling factors. In this study, we aimed to better understand these controlling factors on an underground CO2 leak to the surface in Utah, USA. The study area is located at northern end of the Paradox basin and CO2-charged groundwater effuses in numerous locations (i.e. spring, geyser, seepage, travertine and bleaching). Bleaching is an excellent method to help us trace hydrocarbon pathways and evaluate the scale of natural gas seepage. In this study, we carried out detailed mapping and analysis on various bleaching patterns. Based on the preliminary results, the bleaching patterns are mainly controlled by lithological properties and fracture characteristics. There are some unusual bleaching types, which could be due to the effect of other controlling factors, such as fracture connectivity. Our study provides us with a better understanding of underground natural CO2 leakage to the surface and can help in the design of effective geological CO2 storage.