Mapping Subsurface Fractures Using Seismic Refraction Tomography

Thesis Abstract

Abstract
This thesis investigates the mapping of subsurface fractures using seismic refraction tomography as a geophysical technique. Subsurface fractures play a crucial role in various geotechnical and hydrogeological applications, influencing groundwater flow, geothermal reservoirs, and engineering projects. Seismic refraction tomography is a non-invasive method that utilizes seismic waves to image subsurface structures based on their seismic velocity contrasts. This research aims to enhance the understanding of subsurface fracture distribution and characteristics through the application of seismic refraction tomography. The introduction provides an overview of the research objectives, highlighting the importance of studying subsurface fractures and the relevance of seismic refraction tomography in this context. The background of the study explores the theoretical foundations of seismic refraction tomography and its applications in geophysics. The problem statement emphasizes the challenges associated with traditional fracture mapping methods and the need for advanced geophysical techniques like seismic refraction tomography. The objectives of the study are outlined to focus on the accurate mapping and characterization of subsurface fractures, aiming to improve the reliability and efficiency of fracture detection. The limitations of the study are acknowledged, including the potential constraints of seismic data interpretation and the influence of geological heterogeneity. The scope of the study delineates the geographical area and depth range of the investigation, defining the boundaries of the research. The significance of the study emphasizes the practical implications of mapping subsurface fractures for various industries, such as geotechnical engineering, hydrology, and environmental monitoring. The structure of the thesis outlines the organization of the research chapters, guiding the reader through the methodology, findings, and conclusions. Definitions of key terms are provided to facilitate understanding of technical terminology used throughout the thesis. The literature review chapter synthesizes existing research on subsurface fractures, seismic refraction tomography, and related geophysical methods. Ten key themes are explored, including fracture characterization techniques, seismic wave propagation principles, and case studies of fracture mapping using seismic methods. The research methodology chapter details the procedures and techniques employed in acquiring and processing seismic data for fracture mapping. Eight sections cover aspects such as survey design, data acquisition, seismic data processing, velocity model building, and fracture interpretation methodologies. The discussion of findings chapter presents a comprehensive analysis of the results obtained from seismic refraction tomography data processing and fracture mapping. Detailed interpretations of fracture distributions, orientations, and characteristics are provided, along with comparisons to existing geological information. The conclusion and summary chapter summarize the key findings of the study, highlighting the contributions to subsurface fracture mapping using seismic refraction tomography. Future research directions and potential applications of the findings are discussed, emphasizing the broader implications for geophysical investigations of subsurface structures. In conclusion, this thesis contributes to the advancement of geophysical methods for subsurface fracture mapping, demonstrating the efficacy of seismic refraction tomography in characterizing complex fracture networks. The research outcomes have significant implications for various industries and provide a foundation for further studies in geophysics and geological engineering.